Category Archives: Service tips

Electrical Theory…

Electricals on bikes, everyone hates them right? Why? There is a perception that it’s difficult to understand and is some sort of black magic. It would be easy for me to sit back here and say it’s all basic stuff with the AG200. The problem is I have been immersed in electronics and technology all my working life – nearly thirty years!  So what I find relatively straightforward others may have trouble getting their head around. I get it.

Problem is geeks and nerds (I class myself a geek, don’t know if I qualify as a nerd!) usually have a bad reputation for trying to explain concepts that they understand so I’m going to palm this one off! Down below are some links to some old Yamaha Training info that I had lying around. This is some entry level stuff that hopefully will give you a basic understanding of how electrics work on most bikes.

Electrical Charging Systems

Ignition systems

CDI systems

Electrical Systems 1

Electrical Systems 2

Electrical Systems 3

After reading all this you should have a better understanding of the electrics of your trusty steed.



A standard top-end rebuild kit.

Greetings for the new year folks, hope you all had a good festive break and the new year is a big one for you…even if we are 3 months into it already!

I thought we would start the year off with a bit of a tip for your basic AG200 overhaul. I say “basic” because there is really nothing too bad going on here. When I had a shed full of these things and old trade-ins and barn-finds seemed to follow me home weekly (daily?!), this was my standard engine overhaul kit that I used to keep in stock.

I found that the AG200s lasted somewhere between 15000 to 20000kms with zero maintenance. And 80% of the AGs I fixed that were from farms pretty much had zero maintenance. Oh, they might of had the free first service but after that – nothing. They would ride it until it self destructed! So what I have listed here is the standard top-end rebuild kit that you would have to put through the engine when it got to this point.

Now you might look at the list I have down below and say WTF! Why so many bits AGman? Well, you have to put things into context. It may be hard for someone coming from a different background to get their head around everything I have listed here, I get it. But we are not talking about an engine that has had periodic servicing done here…its had NOTHING for 20000km. And not normal 20000kms either. No airfilter cleaning, probably a clogged oil filter that at least has restricted oil flow. No cleaning so there is probably baked mud in the cylinder/head cooling fins…its a train wreck!

Here is the thing you need to remember most; anything rubber must be replaced. The biggest issue with leaving oil in an engine for this long is that it turns into an evil destructive sludge. If the inner cases look like they have been painted in varnish then the oil has been in for way too long and the chemicals that build up in it destroys rubber and I suspect doesn’t do a whole lot of good for gaskets either.

As for the parts themselves, you can get after-market gasket kits but I have never really liked them. I prefer the Yamaha originals. The timing chain can be sourced after-market, RK is a good brand. Everything else I would go with Yamaha. Lets have a look…

From this exploded view we will require part 6, 8, 13, and 2×17.










From this view we will need 2, 3 and 4









From below –  2×6 and 12.









From below – 2, 7 and 9.










From below – 7 and 11.









And finally, from below – 9 and maybe 2×11 (see text).










To sum up:

1NU-11181-00       GASKET, CYLINDER HEAD 1

90430-14131          GASKET

93211-45471          O-RING

93210-57634           O-RING x 2

93210-72529           O-RING

5LB-11351-00         GASKET, CYLINDER

93210-13361           O-RING

5H0-12119-00        SEAL, VALVE STEM x 2

93210-09165          AA5 O-RING

4BE-15451-03        GASKET, CRANKCASE COVER 1

93210-14369          O-RING

93210-32172          O-RING

94580-41104          CHAIN (DID25SH 104L)


15A-11603-00        PISTON RING SET (STD)

93450-17044         CIRCLIP x 2 (if you need to remove the piston to clean it)

There are assumptions and additions here; The two valve guide seals are needed because most AGs at this stage have been pretty fumy and there will be lots of carbon in the combustion chamber and the exhaust port. you really should pull the valves out to help with this clean-up and inspect the valve faces. I would strongly recommend a grind to clean up the faces – they will probably need it. So if the valves come out, you will need the valve guide seals.

I have covered mostly consumables here. There are lots of parts that need to be checked as well; are the cam chain tension guides going brittle? How does the cam look? Rockers? Valve clearance adjusting screws? Valves? Was the base gasket leaking? How do the cases look where they join up at the cylinder base?  Lots to cover in a later tutorial…

The rubber parts that go in between the cylinder/base and cylinder/head are critical. Re-use the old ones at your peril! Take a look at the three radial seals on the engine as well – counter-shaft, gearlever and kickstart. If one is weeping replace them all because they will be going hard and failing soon.

Don’t be tempted to replace the o-rings listed here with generic bearing shop stuff – all rubber is not created equal. These need to resist oil and elevated heat. Unless you know where to source these o-rings from, go with Yamaha.

Obviously the part number of the piston rings will depend on the oversize of your engine but I doubt anyone would bother boring an AG200 up to the next oversize. If the piston and cylinder is worn out on one of these bikes then the rest of it will be rubble! Check anyway, and while you are there measure, or get someone with the equipment to measure your piston and cylinder to see if they are within specs.

Hopefully I will be able to do a tutorial this year to show the fitment and little tips and tricks of putting all these bits together. Don’t hold your breath though! 🙂



AG200 corrosion points

Corrosion and the AG200 go hand in hand, it’s just part of the world that the bike plays in. Farms, particularly irrigated farms, will eventually cause issues with certain parts of the motorcycle. There isn’t much a farmer can do to stop surface rust under the paint on the frame, swingarm, and other larger parts on the bike, but there are certain fasteners that are particularly vulnerable and if protected can save real headaches down the track.

I don’t  blame the farmer for this one (did I just hear a collective “gasp!” from farmers around the country?), I blame the dealer. Yes that’s right, I said it – it’s the dealers fault! If they spent an extra half an hour during pre-assembly and delivery, it would save all sorts of hassles later on down the track for both the farmer and the dealer/mechanic that has to service the bike.

The dealer would say who cares if nuts and bolts and other parts seize up on bikes and are hard to remove, we just charge the time out to the customer. That’s a typical statement from a person who doesn’t have to work on the bikes! The thing the dealer doesn’t realise is that this sort of frustrating work on AG bikes is discouraging mechanics from staying in the industry. Most mechanics that I know who worked at country dealers hated it and never went back after they left.

This is why I don’t have much time for dealers who say they cant get good spanner men. If dealers made the job for mechanics a bit easier down the track then they might stick around. A mechanic doesn’t care if they can charge out all the time they spend repairing the bike, what they do care about is breaking and repairing every nut and bolt holding the footwells on a Yamaha ATV to get access to do a simple service to the auto drive.

AG200s are a bit more basic than ATVs but the issues are the same; if certain fasteners had anti-seize applied from new, then life would be so much easier down the track for simple maintenance jobs. So enough gas-bagging, what are the problem areas?

Front brake cable clamp bolt.

brake-cable-clampThis clamp is always a problem to remove if left to its own devices. Give it a twist and the head breaks off and you have to drill it out. Dis-similar metals don’t help either so a bit of anti-seize nips this one in the bud.



Front mudguard bolts.

front-mudguard-boltsThought I would chuck in some mud for effect! This is a no-brainer right? Anywhere that gets constant crud thrown at it is going to give problems after a while. Anti-seize on the four bolts and spray WD-40 or CRC under the guard to make the mud slip off.


Front mudflap nuts/bolts.

front-mudflap-boltsAs above, no rocket science involved here.




Exhaust header bolts.

exhaust-flange-boltsThis one you might need to be a bit more careful in removing if they look gumby. Be gentle if they feel tight to remove and use liberal amounts of your chosen release agent (WD-40 etc.), and move them in and out like tapping a thread. These fasteners get too hot for regular anti-seize, so a Nickel based product will be needed. Normal stuff will burn off but its probably better than nothing.

Exhaust guard bolts.

exhaust-guard-boltsThis is a tricky one. If the bike is old and it looks like the bolts have never been removed then it is probably best to leave them in place. They will break off the heads. If your bike is not too old then give them a go. Add a high temp product as above.


Rear mudguard bolts.

rear-mudguard-boltAs with the front guard, these bolts preferably need to be done from new. When removing them be careful and try and lube the threads from the rear. If they break you are in a world of pain because it is hard to get to them to either remove the stud or if you want to drill them out. Frame rails make it difficult to get to them. While you’re under the rear guard, don’t forget to do the two bolts at the rear that do extra time holding up the mud-flap.

Seat and rack bolts

seatrack-boltsThese are fasteners which you think may not give problems but they can catch you unaware because crud can get to them from behind – hit them with your goop!



Chain guard bolts.

chain-guard1We have multiple things to watch here and it’s probably chain-guard2the area that cops the biggest flogging in regards to constant exposure to the elements. All the fasteners in the following photos should garner your attention. Note in the pic showing the clamps on the rubber boot is an AG200 I’ve prepared earlier that demonstrates what happens when these bolts are neglected – they snap off! They then effect the integrity of the assembly they belong too.

chainguard4Sometimes I wonder if this is one of the reasons lots of chainguard3farmers toss the chain guard. It would only take a few of these fasteners to break to make people lose interest in putting it all back together after removing it to replace the chains and sprockets. If you keep anti-seize on all these bits it will make your life a lot happier when it comes time to do this job.

Swing-arm cover bolts.

swingarm-guardThis was a bit of a tough one to show in a simple photo ag200-swingarm-guardreally but next time you remove your wheel you will see a cover protecting the swingarm. This snapshot at right is from that cracker new manual I uploaded last week and it shows the guard better. Its probably a job for when you next do your swingarm bushes…much easier to do when the arm is out of the bike and on a bench, or at least when the wheel is out. Its held in by three bolts, two of which are dodgy self-tappers (the lower two), it’s probably best to leave those alone and just focus on the top bolt which is also the fastener for the shock pivot protective flap.

So that’s probably it. There are a lot of other areas that you could pay attention to like the bolts on the “bark buster” bars, footpeg mounts, rear brake adjuster, engine mounts, etc. But I reckon the ones I have listed here are the biggest trouble makers if you ignore them. Give the bike some love and it will repay it ten-fold.

And just a last word to the dealers…try looking after the mental health of your mechanics, give them input to the pre-delivery and maybe they will hang around a bit longer!



Front mudflap mod.

I know what you’re thinking (again); this guy is getting desperate if he is writing about a mudflap! You’re right, I am. Not desperate for things to write about (I have over 10 unfinished posts) but I don’t like posting without photos. Someone once said that they (the photos!) can say a thousand words…can’t remember who it was now…but anyway, I was going through some of my photos and I found these pics so I thought I could write something about that, so here we are.

mudflap curl2What is it about Ag bike mudflaps? You could go surfing on the silly looking things! They are huge and I bet the original designers were thinking mud right (duh!)? But I think the more important thing here is crap…yep, from a cow! I don’t think there is a more insidious and destructive thing on a farm (weeeell maybe DDT and Dieldrin come close!) than bovine effluent. Problem here is most farmers just leave it where it sticks! That’s OK, they use their bikes as a tool, nothing more. But we as the custodians and/or “discerning” users of the AG200 need to be aware of a few things that might help us with longevity, reliability and general cosmetics of the bike. Work on Ag bikes for a while and you will see that this crud effects everything if left, especially where it accumulates and sits for long periods.

Rubber, aluminium, steel, paintwork and even plastic doesn’t like it for mudflap curlvery long. So you can either wash your bike after every ride or you can do as much as you can to try and keep it off your equipment. I don’t know what the exact material used by Yamaha on the front mudflap is, but it’s not immune to damage from cow manure. I’m not 100% sure if it’s manure or heat from the exhaust pipe but the flap tends to curl up and therefore show a narrow path of protection for anything flicked up by the front tyre.

melted mudflapI have noticed in my travels that the bikes I see on dairy farms are the worst where there’s more crud than other farm types and its also common to see melt marks on the back of the flap from the exhaust pipe and/or being pulled in by the tyre. When they curl up bad you can see bad degradation of the rubber material. Another thing that could contribute is the use of highly caustic cleaners on a lot of farms these days. The actual cause is probably irrelevant if you keep your bike clean and the following mod will make the cause moot as well.

If your bike has been on a farm devoid of cattle then there is a good chance this mod will make limited difference, but for me you should still keep an eye on it because it can cause other issues. This mod can be useful no matter what you use your AG200 for. Take your mudflap off and go for a blast up a gravel road and listen for the stones hitting the underside of the engine and the frame rails, especially if you have a new tyre on and more especially again (can I say that?) if you have a nice sticky motocross tyre on, which you should because it’s insurance for an appalling front end!

A lot of crud can get caught up under the engine and stones can damage the paint on the frame rails, the AG200 has no bash plate and the ground clearance is low so the more you can block rubbish from the front wheel, the better your undercarriage will stay. So while I suggest to do this mod if you are just doing jobs around the farm, I suggest that if you have the curl issue and you use your AG200 for other functions to do it as well.

mudflap modEnough waffle…so what’s involved Mr. hot AG200 mods man (sorry, couldn’t help myself)? First thing…give it a wash will ya! Give it all a bit of a clean up so you can see what you’re doing. I also suggest you remove the flap assembly so its easier to work on. If the bike is in really bad shape the two fasteners holding the flap on will be corroded and they will break or you will have to cut them off. It’s probably a wise thing to replace these bolts with stainless ones if you ever get the opportunity, they cop a flogging. There also should be a plastic spacer (in the photos and item 5 in the parts list) that helps keep a bit of rigidity to the flap to stop it getting pulled back in by the tyre, make sure you don’t misplace it.

mudflap mod3Now you have all the bits apart, give it another good clean up so you aren’t working in crud! Take a look at the photos…pretty self explanatory I’d say, not rocket science at all is it? I used an Aluminium strip with a few M3 stainless screws and plenty of anti-seize. You could use anything you want to do the same thing but just try and keep it light – no 3mm RHS with 1″ bolts OK people?! If I was to do it again I would probably use a plastic strip actually, but anywho…

The whole point is to keep the flap at its wide, effective best as it came from mudflap mod2the factory. You might not think it makes much difference but I’m telling you from someone doing 70 to 80kmh up gravel roads with a sticky Dunlop motocross tyre on the front it made a lot of difference. It costs next to nothing to do so if the things I mention above are important to you then I suggest you give it a go.

So there you go, a big hot mod for your AG200! The elephant in the room here is that you could just buy a new mud flap but I wont go there. They only do the same thing eventually anyway so why not just mod the old flap and keep the cool old agbike patina to boot – nice! 😀



Clutch servicing.

I know what you’re thinking; why doesn’t this clown finish the timing chain replacement tutorial? I would if I could, but I have run out of good photos so I can’t finish it. I am in a life-limbo situation at the moment, to the point that I don’t own any bikes!(*gasp*) Yep, no AG200s – therefore no pics! Before I had a clean-up though, I did take some snaps of some other projects so I will move on to what I can until I get my AG mojo back! Yes, it will be back…

If you follow the comments closely, you will know that I think the AG200’s clutch is a weak point of the bike. I suspect Yamaha knew it too, that’s why they upgraded it on the TW, TTR & XT. Luckily the AGs gearing is pretty low so there isn’t much strain on it, but if you up the gearing or strap on a load you may feel the clutch struggle, especially if its already had its share of usage. It’s not hard to service or repair so lets take a look…

We probably should look at symptoms first. They’re pretty obvious; if you give your AG the berries and the revs rise and you don’t accelerate at the neck-snapping pace you are used too, then there’s a good chance your clutch needs looking at! Is the clutch cable and lever adjusted properly as per the manual? Look at that first. They are prone to shudder too, and gearing them up for a better road speed will amplify it if you didn’t notice beforehand.

What you have to remember with the AG is that there are five friction plates, four steel plates and four miserable springs holding the whole show together. Not a lot of surface area or spring tension when things get tough. So if it gets abused, heat builds up quickly and your steel plates warp. This is especially true if you have been riding it around for a while with the clutch slipping.

This tutorial is about servicing the standard clutch with factory Yamaha parts. They are relatively cheap, easy to get and will last OK in standard form if the bike is not flogged or ridden by a teenager (same thing really!) who thinks they’re Jeffrey Herlings! If you want to upgrade it then that’s a bit more difficult. Yes you can put better plates and springs in it from another model but you still have the limited amount of plates. I will cover a more serious upgrade in a future post.

So, what do we need for the job? That depends. If your clutch is slipping then you will at least need the five friction plates and springs. If you noticed shudder before slippage then replace the four metal plates as well. You can of course measure the warp of the four metal plates like they say in the manual but a bit of advice? Do the lot or you will have unsatisfactory results. Yes, it might not slip any more but shudder sucks…four metal plates dude…like I said it depends…on how tight you are!

Clutch exploded viewTake a good look at the parts breakdown posted here. There is a bit of a trap here for the unwary. The unwary parts guy I should add! Four of the friction plates are the same but you will notice that the third or “middle” friction plate is different. Make sure you get this plate, you will notice it has a different part number. I have seen casual parts guys just order five of the first friction plate labelled “8” which wont work. This middle friction plate is modified to accommodate the Boss Spring (19).

If you’re doing a budget repair then the friction plates and the four compression springs will get the whole thing working again. I strongly recommend you do the whole thing or you will be disappointed. Four of number 8, one of number 18, one of 19 and four of 9. Four pressure springs (11) will also be needed as well as a case gasket. I know it sounds like a lot but it responds well to all these parts and they are not that expensive from Yamaha. Get a price on a WR or YZ clutch rebuild while you are at the dealer if you want to make yourself feel better about it!

When you know the new parts are going in, it pays to let the new friction plates soak in the same oil as you use in the engine. Overnight is good. As always with engine related work, its a good excuse to do an oil change, especially if the clutch has been slipping as it would of been dumping the fibrous friction material into the oil. Remove the filter and the cover from the cases.

footpegWhen you have the oil out, there are a few bits we need to sort out before we can get the clutch cover off. Undo the two bolts holding the foot peg bracket. You can remove the top one and let the whole assembly swing down if you want. Once we have this bracket out of the way you can slide the rear brake lever off its shaft and out of the way. You will have to remove the return spring first to achieve this. If the rear brake light switch is still around you will need to disconnect this as well.

Once all this stuff is out of the way we can remove the kick starter.kick starter Add a kick starter shaft seal to your list of parts if it looks like it’s been weeping oil. Once the bolt has been removed from the kick starter, you can slide it off. If it’s a bit tight you can lightly tap a screwdriver into the split section of the spline to separate it and help it move.

case removeNow that everything is out of the way, we can remove the ten screws holding the case on to the engine proper. Take note of the different lengths and you may need a few gentle taps from a soft faced hammer to break an old gasket. Take note in the photo at left that the o’ring from the filter housing is still in place, it would be a good idea to remove this and keep it with the filter and cover to save it getting misplaced.

Now we can remove the cover, slowly pull it away from the engine remove coverkeeping an eye out for anything that drops out. What can drop out? Hopefully only the locating dowels! You are in trouble if anything else falls on the floor! front dowelIt’s probably a good a time as any to take a look at both gasket surfaces and clean them up with a gasket scraper. Note the locations of the dowels at the front and rear of the engine. Remove them if they will come out and stick them in the recesses in the cover once you have cleaned it up and put it aside.rear dowel

OK, now it’s time to have a look at the clutch. Undo the four 8mm bolts holding the compression springs in. Move across diagonally and remove spring removethem a bit at a time to spread the load across the pressure plate. Not really a critical process on the AG but it makes good practice if you ever work on more exotic stuff in the future.

Now that the compression springs are removed, it’s time toouter clutch2 release the pressure plate. Take a look at my pic at the right and keep an eye on two things; make sure the o’ring on the push-rod is OK, and watch the push-rod ball does not come out and get lost. If you’re paranoid clutch pushrod balllike me (watch for my upcoming blogs on bug-out preparation 🙂 ), use a magnetic screwdriver or other device to remove it and put it aside so it doesn’t get lost.

Now we can remove the plates. One should probably be careful here and keep the plates in order but what the hay, you’re replacing all of them right? Right?! If not, feel free to go and check the clutch section in the service manual. Three things are critical for normal operation; compression spring free length, friction plate thickness and steel plate warp limit. It’s all there in the manual which you can download here or you can buy your very own exclusive copy from eBay here! All that info in one place for 10 bucks, how did this Polish guy pull that off? What a legend! 🙂

Just out of interest, I thought I’d post up a photo of the springs out of the clutch springsbike I was working on at the time. This AG’s clutch was slipping in all gears and was useless. Check the difference between new and old springs. Not much difference eh? But it was a enough, together with under-spec friction plates to make the bike unusable. The AG200 clutch is a bit like my advice on the carburetor series I did a while back; cut corners in maintaining it at your own risk. Same with the clutch, if you cut corners by replacing one thing like the springs and you will soon have more issues and you will be pulling it apart again. But anyway, you get it…that’s enough on that issue.

install platesRight, back to the grind; the reassembly. Only a few things to watch out for here. Check out the manual or the exploded diagram above, it’s pretty straightforward. Friction plate in first, then a steel plate, another friction plate and another steel plate. The middle, friction plate install ballgoes in next, then the boss spring and another steel plate and so on until you have run out of plates to install and there is a friction plate looking at you ready to put the pressure plate back on.

install pressure plateBefore we can do that though, don’t forget about the push-rod ball. Once that’s located we can slide the push-rod on the pressure plate into place and line the plate with the spring posts and we are ready to install the new springs. I like to bring the tension up on the springs as evenly as I can in a cross pattern. A few turns on each spring and then move across to an apposing spring. The torque on the compression spring bolts is low at 6Nm, so don’t get heavy handed with them or you will break a post or strip out a thread – scrap one clutch!

arm adjustThe last thing we need to do before taking sunshine away from the clutch assembly is adjust it. The service manual explains it well but the rough and ready version is to take the slack up on the push-rod adjust pushrod(move the tip of the arm towards the front of the bike) and make sure the sharp end of the push arm assembly aligns with the post/mark cast into the engine case. If it doesn’t, loosen the 10mm nut in the middle of the clutch pressure plate and adjust the screw in the middle until it aligns. Nip up the lock nut when you’re done.

reasemblyNot far to go now folks! Grab the front and rear dowel pins and install them in the engine side of the cases. Install your gasket in the same place so it hangs on the dowels and you are ready to place the clutch cover case back on the engine. Keep an eye out for the earth wire and the starter motor cable locating tabs shown at left. The rest is pretty much the reverse of the disasembly. 8Nm on the engine case bolts, make sure your rear brake is adjusted when you put it back together and don’t forget to put some nice, fresh oil back in the cases!

That’s it, we are done. Now you can go out and at least be confidant that under standard conditions, your clutch will do the job. Keep Jeffrey Herlings off the thing though!



Changing a timing chain. Part#1

AG200 bent inletDoes this AG200 inlet valve look a bit wonky to you? It should…it’s been smacked by a piston! This is what WILL happen if you neglect your timing chain. It’s all easily preventable though and the bike tells you when it needs changing. The diagnosis and remedy is all pretty straight forward. Lets have a look at what’s involved.

First the diagnosis…does the timing chain need changing in your AG? There are a few components in the AG200 engine that, in my opinion, are marginal and can wear out quickly if neglected. The timing chain is one of them. It was upgraded to a stronger assembly on some of its sister engines and that suggests to me that it was borderline, and Yamaha knew it. Consequently, I tend to be overly cautious of its maintenance and replacement regimes and as with most engine components, oil changes are its biggest life-extender.

So replacement time is pretty simple; if you can hear the chain rattling around in your engine (preferably when its running!), it needs replacing. That’s how I roll with the timing chain in the AG200 anyway. The chain can be had for $20 and with an oil change and a few gaskets you’re looking at around $50 or less for this preventive maintenance. That’s a lot cheaper than leaving it until it spits the dummy! If you have a second hand bike that has missed a lot of owner love then you can keep an eye/ear on it and replace it if it’s noisy. Once you know its been renewed keep fresh, quality oil in the engine and it will repay you with good reliability.

If you neglect oil change intervals and ignore the AG200 timing chaindeath rattle coming from within the engine, eventually the chain stretches and the tensioner will not be able to do it’s job of keeping the chain on the sprockets. Before it finally chucks the teddy in the dirt, in an act of defiance the timing chain will slap around, grinding into the inner walls of the head and cylinder (see pic at right), showering the engine internals with alloy swarf before finally flinging off and causing grief proportional to the RPM you’re doing at the time.  If left to these extremes, it will cause issues down the track by spreading metal around the engine. The 3GX is a tough old lump, but no engine likes metal in it even if it’s soft metal.

Please, please, pleeeease don’t think you can extend the tensioner shaft! Yes, a lot of people on-line say you can extend the “service life” of the timing chain by adding some length to the tensioner shaft that puts the pressure on the chain guide. You can buy a new chain for less than $20 and one, maybe two gaskets and the head or cylinder doesn’t need to come off to do the replacement. Why would you bodge it up like this? When the chain starts to rattle, its worn out. All it does now is start to wear the timing gears which are not listed as a replacement part on the crank end. So if you wreck this gear you wreck the crank. Don’t be a hack, spend the 20 bucks!

OK, so lets get into it…this is what you’ll need;

TOOLS; 8mm hex socket (or Philips for the older bikes), flat blade screwdriver for timing/flywheel bolt covers, 17mm socket, extension and square drive for the flywheel bolt, Flywheel puller (M16 x 1.2mm), Flywheel holder.

PARTS; 104 link timing chain, stator cover gasket, timing chain tensioner gasket, oil.

Kick your bike in the guts (Aussie speak for start it up!) and warm it up (you haven’t let the timing chain fling off have you?!), shut it down and drain the oil out. A general service is a good time as any to do this timing chain job so clean the filter and dispose of the oil. When you’re done, stick the drain cap and filter cover back on and nip them up.

WAIT!!! Stop! Sorry to be so dramatic…but before we go any further, when you do change your oil, check your oil filter and mesh strainer for any signs of black plastic chunks. If there is any black rubbish in there I’d say your timing chain tensioners have gone brittle and are starting to fall apart. This is a sign of pretty serious neglect though so it’s not that common to see. If you do see it then you wont be able to do this job without taking the top end off to replace the tensioners which I will cover in an up-coming blog. Its not that common to see but I thought I’d mention it at this point in the disassembly.

OK, the tensioners are fine and we can continue with the chain swap. Every major (or even minor) maintenance job on a motorcycle should start with a good clean. Not only paying attention to the areas that will be worked on, but the whole bike really. Pull off the tank and seat and scrub it all up. Rubbish likes to accumulate up under the tank around the wiring looms and on top of the head and just loves to fall down into your opened up motor!

We have a section that we need to pay particular attention to with this procedure – the front sprocket area. If we don’t get this area nice and clean before we remove the stator/flywheel cover, all the rubbish that will be in behind there will try its best to get inside the motor. So turn your attention to the front sprocket cover. Remove the gear shift lever by removing the 10mm hex head bolt and sliding the lever off it’s spline. Remove the two Philips screws holding the rubber cover to the plastic sprocket cover. Two more bolts are required to remove the front sprocket cover.

DSC_0045You will now have access to the front sprocket area to get it as clean as you can. Take your time and actually, if you have a pressure washer, now is the time to put it to good use. Otherwise, pry out as much rubbish as you can with a pick or screwdriver and finish off with de-greaser and a stiff brush. Removing the drive chain and front sprocket will make this job even easier. The pic. at left shows a partially disassembled bike but it will give you an idea on how clean it should be. The wiring in the photo is also relevant as we get into the job.

top timing gear cover Remove the two bolts that hold the top timing gear coverStator cover. Early bikes had Philips screws while newer bikes stepped up to 8mm hex heads. When the bolts are removed you can take off the cover and view the top timing gear. Next job is to remove the two inspection caps on the stator cover. The small upper one is to give you visual access to the timing marks on the flywheel while the larger, lower one allows you to get access to the flywheel bolt so you can rotate the crankshaft.

Timing markRemove the spark plug and insert your square drive socket into the flywheel bolt hole and rotate the crank so the timing marks line up. The flywheel mark can be seen at left and you can see the other one in the above photo of the top timing gear. The mark on the gear should line up with the pointer cast into the head right at the top of the gear housing. You don’t have to get too pedantic with it all at this point, the reason I do this first is to get any tension off the valve assembly so when you start undoing bits it wont fly off everywhere because the cam is sitting up on a compressed valve spring.

I would now take the opportunity to loosen off the top cam gear bolt. Use your square drive socket to hold the flywheel steady while you get another 17mm socket or spanner onto the bolt holding the top gear to the cam. Get it loose and leave it alone for now, we will come back to it.

Now the eight stator cover screws (for later, electric start bikes) can be DSC_0041removed and a light tap on the cover with a soft faced hammer might be needed to jar the cover free from an old, hard gasket. Once you have the case loosened off, have a look at the wiring going to the stator cover and work out if you want to disconnect the connectors from the loom or have something handy for the cover to sit on close to the bike while you are poking around on the engine. I like to disconnect the wiring and remove the cover completely from the workspace but it’s up to you. Take note of the neutral switch wire which also needs to be removed, shown at right of this paragraph.

Be aware that there will feel like there is resistance when you pull on the cover because of the magnets in the flywheel trying to hang on to the steel coil formers of the stator. Just be careful especially if you have left the wiring attached. Also take note of the two locating dowels in upper and lower rear screws of the case. These dowels like to fall out and go missing at times! Download the manual and check out the (p. 121, ref. 4) diagrams if this is all getting confusing.

DSC_0031When the cover is off you will see the flywheel…which now has to come off. But before we do this we need to remove the starter idler assembly as shown here at left. Remove the aluminium washer in front of the gear (just behind my finger and thumb in the pic) and slide out the shaft and you can then remove the idler gear. Now we can remove the flywheel. This is a really easy job for me because I have a cordless impact gun! Getting flywheels off used to be a real chore when I was a kid. Getting the nut/bolt off was hard enough and then removing the flywheel without a puller was always an adventure! Doing things to engines that make me shudder now!

These days with the correct tools, this job is a snap. With a puller flywheel & pullerand a rattle gun, I don’t even require holding the flywheel with the removal procedure. Releasing the retaining bolt and flywheel from the crank are both quick and easy compared to trying to do it with spanners or square drive tools. At right is a picture of an example of a set-up you could use if you don’t have a rattle gun. It shows a holder and the flywheel puller installed ready to pop off the flywheel. There are a few variations of flywheel holder tools and this photo is kindly supplied via “SpudRider” over at China Riders Forum and is showing the procedure on his Zongshen GY-2 which has a very similar engine to the AG200. How you get the flywheel off is ultimately up to you. Buy, beg or borrow the correct tools to do the job or you will have to resort to bashing things which normally never ends well!

OK, so you got the flywheel off. Check the manual again (p.123) to see what you need to keep track of. There is a woodruff key (ref.4) that may or may not dislodge from the crank and a washer or shim (ref.6) that sits behind the flywheel that may or may not stay on the crank. Watch what happens to these items. Also try and keep the whole flywheel/starter clutch assembly together if you can. Bits can go everywhere if they come apart…its no big deal, its easy to reassemble but if you slide it all off as one unit then it makes it all easier.

DSC_0007Put the flywheel/starter clutch assembly aside and you should be looking at the pic at left. Note that the washer that sits behind the flywheel is still on the crank and the woodruff key has been removed from the crank in this photo.

Lets turn our attention to the timing chain tensioner. First DSC_0042thing to do is loosen the 10mm bolt on the centre post. Don’t remove it, just loosen it for now. Now remove the two Allen bolts at the top and bottom and remove the DSC_0010tensioner from the cylinder. You will feel the pressure that the tensioner exerts on the chain as you loosen the two Allen bolts.

Remove the timing chain tensioner assembly and you will have a nice slack timing chain that you can slip off the top timing gear and let drop down the engine to the crank shaft and lower timing gear. DSC_0013The top timing gear can be removed to help facilitate this – or not. Sometimes the chain will be loose enough that it will lift off the side of the gear and you can just let it drop down to the the crank and remove it.

That’s the removal part done. True to form it was getting a bit long so I will break it up into two parts; removal and reassembly. My only other suggestion before signing off is to jam some rags into the engine cases and clean the gasket surfaces on the engine side and stator cover ready for reassembly.

Keep an eye out for part two…



Front wheel bearings and other horror stories

Let me tell you a story that I think you will find hard to believe. I find it hard to believe. In fact, if I hadn’t seen it with my own eyes, I wouldn’t believe it. I wouldn’t want to believe it anyway. It’s basically a story about low IQ, and motorcycle ownership with a bit thrown in at the end on how to replace front wheel bearings on your AG200!

A few years ago before the end of the naughties, I was helping out at a small, country Yamaha dealership. The owner was between mechanics and I thought I would help out with the spanners for a few months while he managed to track down another victim, errr employee! For the six months or so I was there, I saw mechanical horrors that no technical person should ever have to see. I still have nightmares to this day…

Things that make you incredulous that we are the dominant species on this planet! Things that make you shudder and doubt that humanity even has the right to go on! There will always be one encounter though, one special “Bobby Dazzler” example of how far someone can push the boundaries of neglect and stand out from the crowd, and man is it a special crowd! It’s one of those things that you wont forget until your final days. Unfortunately this experience for me involved an AG200.

The experience in question started as I was labouring away, minding my own business in the workshop when a guy shows up in his 4WD with trailer in tow. Alarm bells went off before I even got a look at the bike because the poor thing was chucked in the back of the trailer with no restraints. Yep, just tossed in on its side! My idiot detector went off instantly and thought he can unload it himself if he is too pathetic to even load a bike up properly (I never was a good long term employee!). A few minutes later he pushes this poor thing into the shop,  leaves his name, address etc. and off he went on his merry way mumbling something about “they don’t make ’em like they used too.”

After he drove off I thought I’d have a look at the treasure he left us to repair. I wish I had taken photographs, I really do wish I did. The guy was complaining about front end problems and boy did he have that! The front wheel bearings had collapsed completely to the point where the ball bearings were gone…completely! Now you can forgive someone for  a bit of play in their front end but can you imagine the play this thing had? let me tell you how much movement was in the front wheel; it was hitting the forks!

But wait, it doesn’t stop there dear reader. When the bearings collapse in the front wheel of your motorcycle, you’re going to notice it right? You’re going to think; “Oh, better get that looked at, this thing is getting a bit wonky to ride.” But noooo, not this clown! I don’t know how long he rode it like that but it was long enough for the tyre to wear through the fork legs. Yep, through the fork legs! The Aluminium just under the oil and dust seal was removed right back to the slider on both forks, where it had rubbed the chrome off them as well.

Believe me? I wouldn’t. Unless I had seen it myself with my own eyes, I would find it hard to swallow this story  if someone had just told me. I should of taken photos but at the time I think my brain was in some sort of paralysis because of what I was actually seeing. I actually took it for a ride and concluded that it could only be worse if the front wheel had actually fallen off. Diabolical was the only word that I think comes close to how that bike rode with the front end like that.

The whole front end was scrap in my books but the owner insisted that he didn’t need brakes (the hub was all mashed up), or the pesky oil in the forks, slap some new bearings in it and he was good to go! The axle, spacers and inner bearing races were a big, corroded blob of destruction and he screamed at the cost of new, genuine replacements, which I thought were a waste on this moron’s bike anyway. Surprisingly, some new bearings actually fitted and stayed put in the hub, we nicked the other bits off a wrecker and off he went, still bitching at the cost of it all!

I always wanted to “out” this guy as the mechanical terrorist that he is, but what would it achieve? He is still destroying farm equipment to this day and will until he’s in a grave. I always thought, and was taught, that farming was a business. So why don’t farmers treat their equipment as part of their bottom line? It has always baffled me but the answer is probably that a lot of farmers, particularly in the past, never had much concept of  business anyway. Time has caught up with a lot of them. But I digress…

What’s with the story AGman? I thought this post was about front wheel bearings? Well it is but there’s not a lot involved with front wheel bearing replacement so I thought I’d put that entertaining little ditty in there so you will know how to avoid rubbing holes in your fork legs!

Off you go to the Front wheel removal section of my fork repair tutorial. This will give you an idea on how to get the front wheel off and what you have to do to achieve it. Once you have your wheel off and your stolen milk crate ready, place the wheel on it with the brake side facing down. This bearing is easier to knock out because it doesn’t have to pass as far in a press fit as the non-brake, seal side.

Get yourself a long drift or punch and slide it down the centre of the bearing until it reaches the opposite bearing’s inner race. You need a punch in pretty good condition with a good edge so it will hang up on the bearing. A few good whacks with a hammer and it should come out fine along with the centre spacer. Turn your wheel over and you will have much easier access to the opposite bearing which is a bit harder to move because, as mentioned, it has to pass through about double the material before it will drop out of the hub. You can remove the seal before you knock the bearing out but it doesn’t matter, it will come out with the bearing either way.

This is the rough method of removing the bearings. You can get special tools that expand in the inner race of the bearing and then with a slide hammer, you can remove it. Not everyone has easy access to these tools and they can be expensive. I have heard of people using DynaBolts (concrete or sleeve  anchor bolts) to use in bearing removal which is a good idea but may still need a slide hammer if you can’t bash the bolt from the opposite side, which you should be able to do. I will do some experimenting and check it out in an up coming post.

P1020583Back to the job…get yourself a couple of rubber sealed, 6301 bearings. I like SKF and NSK but any of the good bearing brands will do. I also pop the covers off the bearings, flush out the “grease” and replace it with a quality, waterproof substitute. I don’t expect you to do that but if you’re doing big miles on your bike I would defiantly recommend it. While you are at the bearing shop, get yourself a 18x37x7mm seal, they are cheap (as are the 6301 bearings I might add) and you might as well replace it with the bearings.

Installation is pretty simple. Find yourself a useless SAE socketP1020577 (American readers are gnashing teeth!) that matches up to the outer race of the bearing but doesn’t hang up on the hub. You can use this to gently tap the bearings into their P1020580new home. Don’t forget the inner spacer! You should also be able to install the new seal nearly by hand, if you do use persuasion, be gentle. Have a look at the photo of the seal below at right. Make sure it’s not flush with the hub. There is a plastic collar that fits on the axle spacer that slightly overlaps the hub a few mm. This helps to keep rubbish out of the seal and therefore the bearing. The link above showing the wheel removal procedure has some good pics if you need them. If this collar is damaged, it should be replaced for the long term health of everything discussed here.

There we have it, use grease on the seal lips, spacers and axle on P1020587reassembly. Make sure the speedo drive lines up correctly or there will be carnage. Another tip is to get someone to hold the front brake lever firmly to centre the hub while you are tightening the axle nut. We are done! Cheap, easy and no excuses for damaging those fork legs!



O’ring chains on the AG200. Really?

Some people that have recent history with the AG200 might be surprised to learn that the first model released way back in ’83 – ’84 was supplied with an o’ring chain for the final drive. What?! Why go to all the trouble of designing a fully enclosed final drive system and then add an o’ring chain? Yamaha must of asked themselves the same question because they stopped doing it not long after the original release. What about now? Is it worth the expense to prolong the life of a component that, if maintained correctly, will last for ages? My thoughts on the matter follow…

Chain gaurdI have some dealer friends who swear by putting o’ring chains inside the chain enclosure of any AG200 that passes through their workshop. If you are a belt and suspenders type of person then I guess you would consider this a good idea. On farms that get chopped up by cattle (deep, sloppy mud) during the winter (Dude…get an ATV!), this is probably a good idea. The factory chain enclosure is great when set up right but it’s not perfect. The lower guard has a drain hole at the lower section and if this part fills with mud and the drain hole blocks then you have a factory chain and sprocket destruction device!

An o’ring chain will not enjoy being operated in a bath of corrosive, abrasive slime but it will last way longer than a conventional chain. So in this sort of environment where people tend to not give the bike even a fleeting glance between times when the bike stops running (known by a lot of farmers as the “service interval”), then I would suggest an o’ring chain a wise investment.

Now for the rest of us…I have never bothered with an o’ring chain on my AG200s because I know how much power conventional o’rings can suck out of a small engine. I don’t know about you, but if I have a bike with less (waaaaaaaay less!) than 20 HP out the back wheel then I don’t want to let any of that go! The AG doesn’t have much horsepower to start with so sucking a little bit out with an o’ring chain wont do it any favours. I also believe if you look after the chain guard properly then it will do nearly as much to protect the chain as any o’ring will.

Some of these new, low friction X ring chains might work better for the AG but once again, vigilance and preventive maintenance, in my opinion, will prevent the need. There is no horsepower to stretch the chain, so if you keep it adjusted, lubed and relatively clean, which the factory enclosure will do, then you are safe with a conventional chain. Spend the money you saved on chain lube and live happily ever after!



Oil change tips #2 Changing the oil.

OK…we haven’t got our hands dirty for a while so lets get something techy done –  the humble yet often overlooked oil change. Pretty simple really but there are a few little tips here that might work good for you and your AG. As Jamie Oliver says; lets tuck in!

First things first, take your bike out for a good thrash! That’s right, give it the berries! The oil is (or should be!) thick in the AG200 so make sure the oil is nice and hot. I use a procedure here that leans the bike over on both stands for a period of time so the hotter the oil is the longer it will flow well and therefore drain well.

Remve drain capAfter you have set a new land speed record, get the AG into your shed and get it over on the right hand stand. This gives you easy access to the drain plug. Get yourself a 19mm single hex (go and see my discussion on the drain cap here) socket to release the drain cap and place something under the AG to catch the oil. You might have to juggle the gear lever to remove the cap and actually, you can remove the lever if you want because it does make things a lot easier and it’s only one 10mm bolt. If the cap feels like its going to give you pain removing it, give the end of your 19mm socket a firm tap with a hammer while on the cap to help loosen it.

When you get the cap loose and you feel it’s about to pop off, Drain oillean the bike over to the left side stand. Make sure you move the oil drop container to suit. Now you can totally remove the cap, spring and filter gauze and drain out that old Middle Eastern Gold. As the oil is draining on the left hand side, take the opportunity to remove the oil filter cover and the oil filter on the opposite side of the bike.

Filter housing screwsOn later bikes (’98 onwards) you will need to remove theFilter housing2 two top 8mm hex bolts and the lower 5mm Allen bolt. Older bikes use Philips (see at left) on the top two bolts. Remove the cover carefully and pay careful attention to the rubber o’rings under the cap. If they look daggy, replace them. Pull out the filter and have a good look at it, I have discussed in other posts about the filter specifics so if you think it looks dodgy, replace it. If it looks OK give it a wash, remove the metal from it and it’s ready for another service interval.

While the oil is draining and the bike is on the left side stand you might asFilter cove2 well have a good look in the filter housing and give it a bit of a clean out with a rag. Oil would of dribbled down the casing after removing the filter cover anyway so while you have the rag handy you might as well clean out the cavity or filter housing.

Drain capWhen the old oil slows to a drip out of the left side oil drain, lean the bike over to the right hand stand. Make sure you shift the drain container to suit the oil drain. A bit of oil drain might pick up but probably not. The oil is draining internally as you will see later. Take this opportunity to have a good look at the drain cap. Is the o’ring OK? If not replace it. Now give the cap a good clean, remove the o’ring and have a really good look at it. Most people do it up too tight, even Yamaha do it up too tight! It can easily crack around the edges near the o’ring grove. Yamaha specifies 43Nm for it and that, in my humble opinion, is crazy talk! It’s at least 10Nm too tight.

OK, the bike has been over on the right side stand for ten minute or so right? Time to lean it over on the opposite stand. Get ready to move the catch tray, more oil will start to drain. I like to combine the oil drain with a few other maintenance jobs (valve clearances?) so you have the time to go left and right on the two stands for an extended period. If you don’t have the time then fine, a couple of times back and forward will do the trick.

We have all the oil out, now it’s time to reassemble. Your oil filter is new or freshly cleaned so its time to get it back into the filter housing. It can only go in one way so don’t stress. Install the filter cover and tighten up the bolts. Make sure that bottom Allen bolt does not hang up on that small o’ring and damage it. Put a bit of fresh oil on the bolt and the o’ring. The two top bolts are set to 7Nm while the lower Allen bolt is set to 10Nm. Not very tight so those used to hanging off a wrench with a piece of gal. pipe will learn all about Easy Outs and HeliCoils pretty quick!

Drain filter+springLets turn our attention back to the drain cap and its’ related parts. Is the spring and wire filter OK? Not much to go wrong with the spring but make sure there is no rubbish in the filter. Lean the bike back over to the right side and slap them back in the way they came out. I like to put a bit of grease on the alloy mating surfaces of the cap – i.e. the lip outside of the o’ring. You can now screw the drain cap back in and as stated, it doesn’t have to be too tight.

So here comes the biggy – what sort of oil? I have two modes of thought on this issue. If it’s an old bike that’s a bit of a basher and a bit worn and daggy – mineral oil and change often. Newer bike that you want to keep for a long time, do trips on and want it to last and give years of reliable service? Full synthetic. The common ground between them is go heavy. 10W40 minimum, preferably 10W50. You will find the gearbox works much better with a heavier oil. Remember, the AG200 was designed back when consumer synthetic oil was expensive and/or hard to get and the clearances and design has not changed since that time. Also remember, bike oils only, wet clutches dislike car oils and their friction reducing additives.

Oil fillerThe spec from Yamaha is 1.1 Litres with a filter clean/change. Oil fill3Remove the filler plug and use a funnel or a pourer with a tube that fits into the filler hole. Pour your oil in and use the sight glass to get the level right if needed. Screw your filler cap back (clean around the cases and check the o’ring on the cap) and you’re good to go. The paranoid among us can undo the 10mm oil pressure check bolt (circled at right) in the head to make sure there is pressure up there. You don’t have to totally remove it – just loosen it to the last few threads and if there is pressure it will find its way out. Be real gentle doing this check bolt up…5Nm and no more or it will snap off.

So there you go, wasn’t too hard was it? Now get back out there and improve on that land speed record.



Oil change tips #1.5, aaahh, spare parts guys…

This entry is a bit of an addition to my old Oil Change Tips post I did quite a while ago. Just a bit of updated filter info that I thought I would drop in here to give you guys and girls a heads up. After all these years, I thought mechanics and spare parts guys would have sorted this out but we still have an issue of imparting info from one person to another so we still make catastrophic mistakes like the one I’m about to show you.

TTR250 filterI also own a TTR250, a great bike which has a a long model run with few alterations, like the AG200. Another thing it shares with the AG200 is a nearly identical oil filter, the only difference is four little holes in the relief valve end of the housing. Take a look at the photo at left. Have a reeeeeal good look! You will see what the AG200 would see as our equivalent to methamphetamine; something that will trash your head (see what I did there?). If you put this filter in your AG, you will starve the head of oil and the first thing to grenade is usually the cam will seize in the cam gear side bearing. Not good.

Now, have a look at right. This is what the proper AG200 filter looks like.AG K&N These four little holes are the life-line for oil passing through the filter to get up to the head. If someone has given you a filter that looks like the one above for your AG, TW, XT, TTR230 or old ATV, then slap them! The AG has been around for 30+ years and the TTR250 for 20+ but I still hear stories and read on forums that parts guys and mechanics still mess it up and trash perfectly good engines.

K&N AG Vs TTR250Here is a pic of the other side of the filters and I guess you can understand how people could make the mistake, but I reckon the rubber is blue on the TTR filter for a reason! Yamaha had heaps of issues with this a few years ago, probably when the TTR250 first came out I’d say. So stay vigilant people, especially if you are buying cheap filters off Ebay from people who couldn’t really give a hoot about your bike. But also if you are buying genuine parts from a Yamaha dealer because, to be honest, that where I have heard of most of the stuff-ups happening.