Tag Archives: Yamaha AG200

AG200 YouTube vids

Because the AG200 is a bit of a…ahem…lowly steed, when you do a YouTube vid search all you will ever find is poor old AGs towards the end of their lives getting abused. Monster burnouts, monster boghole attempts and all sorts of other antics by mostly bored kids. This seems to be the order of the day for AG200s on YouTube. Not that I don’t enjoy a good monster burnout mind you, but the AG200? Pft! Isn’t there anything more interesting that someone is doing on them?

Imagine my surprise when this bobby dazzler popped up! This is what I’m talking about. If this guy ever comes across this blog, drop us a line!

Until some of you other guys get your trips done, documented and up on the ‘Tube, then this guy is the current World AG200 Touring Ninja!

Cheers

AGman

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!

Cheers

AGman

ADV rider forum thread…

Have been getting a few hints from visitors to expand my horizons and make it easier for people to add to the discussion on the AG200. A forum may be coming in the future and not everyone is a fan of the current social media options so I’m thinking a thread on ADV forums is probably a good compromise for now…it was suggested by one of the guys who has left a comment here; Richard who is planning an epic African trip on his AG200.

I don’t know why I didn’t think of this, bit of a seniors moment I suppose! I would guess that most readers here would probably be members on the forum, or would at least know of it’s existence. Maybe I was a bit intimidated by the hardware on this thing but hey, if the DR200 can be represented then I’m sure we can!

So lets see what the AG200 can really do out there in the real world.

Check it out here.

Cheers

AGman

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.

Cheers

AGman

AG200 Japanese site.

The Japanese made the AG200 so you would expect them to have a little bit of a fan base right? Well they do. Go and check it out here. You will have to use Google translate to glean anything from the writing, but if you persist you will find a few nuggets, like the 6 speed gearbox on the early Japanese version, and the brochure is cool, wonder if they did an English version…

Cheers

AGman

Parts listings…more AG200 gold!

Welcome to the new year of 2015, hope ’14 was a good one for you. I thought I would start the new year with a bang by posting up the AG200 parts lists. I have most of them but thought I would link to an older model (1988), and a newer model (2003). This will help you bypass the incompetent Yamaha spare parts guy if you are unfortunate enough to have one in your area! Select your part number and supply him/her with it so they cant stuff it up!

Its also interesting sometimes to enter the number in Boats.net’s excellent Yamaha parts listings to see what, if any, other Yamaha models use the same part.

Apart from a few new bits on the current AG (2013 onwards), these two parts lists will cover most parts and their numbers. The ’88 manual has the listings for the earlier yellow bikes and the later beige ones, which is handy if you’re after a specific colour part like side covers, guards or a tank.

Enjoy!

2003 AG200

1988 AG200

Cheers

AGman

To forum or not to forum, that is the question…

I love doing my blog…don’t get me wrong. But it’s all a bit one sided don’t you think? I’m getting a lot of good feedback from people here and it’s much appreciated but I’m not naive enough to believe I’m a world authority on the AG200, and in particular the 3GX engine. Is it time to bring other views and ideas to the AG200 platform with a forum? There are issues with forums though, lets discuss.

There are some things I really dislike about forums and the people that run some of them. They always start off saying no advertising will ever be seen on this site…bla…bla…bla! And within a year or two there are adds all over the place! Or the one I despise much more is where people start a forum and wait for a couple of years for members to build up a body of knowledge and then they lock it up behind a pay wall.

From my perspective, there could not be a bigger insult to someone sharing their hard won knowledge to the world, particularly a forum where you are attracted to the site to share with brothers and sisters in a common area of interest. This “crowd sourcing” is a scourge in my opinion, especially when the “crowd” don’t know their making (sometime in the future!) a living for some other slacker!

So I’m not saying that if I start a forum that I wont explore ways to cover the upkeep and maintenance costs, I will. I spend enough time deleting the spam and trolls off this blog, I can only imagine the time needed to maintain a forum! I may look into advertising but it will be targeted and specific to the AG200 and the owners – no Viagra or Xbox adds! If I can’t target, I wont run adds, period. I wont lock up info behind pay walls, even if it’s posted on my forum, I don’t believe I own that info, the members do.

So, what do you all think? Comments? Suggestions? Let me know if you think this is worthwhile pursuing or not. I will of course continue writing up my blog entries, nothing will change on that front. I just think that we may be able to add more to the body of knowledge if others can contribute and have an easier way for people to ask questions and get answers.

And before I sign off for 2014, I’d like to wish all readers a safe and happy festive break. Take it easy, make sure you get through it so you can come back to read more enthralling content on the AG200!  🙂

Cheers

AGman

 

Why the AG200? No really…why?

I have a bit of blog-burnout after the carb clean series, so if you’re looking for info and tips for the AG200 then you should move on to the next post! This one has little to do with Yamaha’s AG bike, it’s more about me and the answer to why? Why do I bother with the AG200?

A friend of mine (old time biker) told me once if you really love bikes you will love them all, and that if I really wanted to restore classics, then start with an AG bike because if you can get an old AG bike back on the road then you can get anything back on the road! He was right. I started working on AG bikes years ago and bringing them back from the brink always seems more fulfilling than other bikes.

The only way I can describe it is what I call mechanical sympathy or mechanical empathy if you like. It has effected me since childhood; I hate it when people abuse and neglect machinery. Silly huh? I understand that these things are just tools to get a job done but I have got to the point in my life where I stop trying to suppress things that people tell me are weird or stupid…when something is in your blood let it go!

I have empathy for living things too like most people, but unlike most people if I see a machine suffering it eats at my engineering soul! No one abuses machinery like farmers, and I pity any poor machine that falls into their hands! I get a pile of rubble off a farmer and re-task it to other areas, to other people who, even though they don’t treat them like I do, still give them a much easier time than their original owners.

Back from the deadTake the two AGs in my workshop at the moment…it’s like bringing back the dead! The later ’03 blue one on the right in particular is in diabolical condition to the point where I have put the engine aside for another day! I have another engine for it and I am slowly bringing it back to a point where I would be happy to ride it myself one day out into the bush.

I already have a friend interested in the machine and he takes notice of the project to the point where I hope he will take it on when I’m done. Life is slowly being injected into this bike part by part as I restore or replace them. It’s a cool experience that I find relaxing and fulfilling while not very profitable! But I don’t do it for profit, I do it for fun and strangely, I am slowly starting to build a small community of mates who sometimes enjoy the slow, two wheeled world out in the boonies.

I think a lot of us who are technically minded (three quarters of the world population can stop reading right here!) like to master something in their lifetime. I would like to master the AG200. I am a long way from it at the moment but it is something I enjoy working towards. Whether its the model history and the part changes between those models, the maintenance tips to prolong the service life, cheaper and/or stronger parts options than the Yamaha stuff or just the small mods to make it better at a particular task, I would like to be an AG200 Ninja!

Now, time to check back into rehab…

Cheers

AGman

Carb servicing part 3 – cleaning

Now we get to the boring bit – cleaning! But in respect to a carburettor, it’s the most important part because if you rush it and cut corners you will be pulling the carb out of the bike again – I guarantee it! The hardest parts to clean in a carb are usually the ones that block and cause trouble in the first place. Take your time and get everything as clean as you can and you will have success. Let’s get into it…

OK…what will we need in the way of tools and consumables? I have already covered the screwdrivers required and what to watch for in relation to them.  You will need a can or two of carby cleaner, compressed air, a small brass brush, cotton buds, rags (preferably clean and white so you can see what comes off on them), your workplace needs access to strong light so you can see through the holes in the metering jets to make sure they are clean.

protectionAs for safety – I have already mentioned gloves, some eye protection is essential because you will be dealing with high pressure air and cleaners. I prefer the full face shields because I am ugly enough thank you very much and I don’t want to be made more so by high-velocity bike bits! Think about ventilation and air circulation as well – too much carb cleaner vapours are not good for health.

What about an ultrasonic cleaner? Do you really need one? If you go and spend some bucks on a cleaner don’t think it’s going to do all the hard work for you. Cheap ones will do a reasonable job but only expensive, dedicated high power units will get them close to spotless. The cheaper ones like the one I use will get stuff reasonably clean but can’t go the extra mile with hard to move deposits. Do you really need one? No, not if you are doing just one carb. Just get yourself a couple of cans of carby cleaner and don’t be scared to use it.

Even if you do have a ultrasonic cleaner, if your AG is fumy and the carb was sucking a lot of oil vapour via the crankcase breather, a cheap ultrasonic cleaner may not get the job done. A solvent like carby cleaner will be needed to clean the baked oil residue out of the venturi of the carb. This is a good “tell” on the condition of your bikes engine; black oil residue in the main air-flow passage? You are probably going to have to do some engine work soon. But let’s get the carb sorted first.

carb bodyI separate the components into two groups; the main body parts, and the small, functional parts. I can place the carb body, float bowl, throttle shaft, cable bracket and other larger parts into the bath of my cleaner. You may have a different size and have to spread your cleaning out differently. I pour hot water into the in the bathbath and add a small amount of dishwashing liquid and set my heat on max (70C in my case) and run the ultrasonics for an hour. Sometimes I have to give it another thirty minutes or so but an hour usually gives me pretty good results.

small bitsThe brass brush will come in handy here. Use it to break up any caked on crud on the outside of the carb body. Pull the parts out of the cleaner one by one every 10 minutes or so and give them a bit of a brush if stuff is hanging on. Don’t try and jam the brush down the venturi if there is baked on oil, let the carb cleaner do that job later.

When the parts are done, you need to get them dry. If you live in Australia or another country with an excess of sunshine, get them into the sun and let them cook! after washIt won’t take long for the Aluminium and Brass components to heat up to the point where water won’t hang around them. If there is no sun to use, get them in front of a heater to dry off. Temperature and time is what you need to get them moisture free. Of course you can use compressed air to blow all the water out, which I do but I also like to heat it up as well. If you’re happy with just the air then happy days.

Choke & pilot adjNow that everything is relatively clean and dry, it’s time to get serious with the carby cleaner. Let’s start with the carb body. You have your gloves and eye protection on right? Give the carb a good blast with the cleaner and try and let the cleaner sit on the aluminium without evaporating. Lower temperatures will help here so try and do it out of daylight. Choke & pilot passLetting the cleaner soak into any deposits will help you a lot. If there is significant oil deposits in the venturi, use a rag covered finger soaked in cleaner to give the area a good scrub. Some choke pickupcotton buds soaked in cleaner may help in harder to get areas. Blast the whole thing with compressed air paying particular attention to the small passages leading to the pilot jet/bypass and choke plunger. Rinse and repeat!

In this photo at left you will see a view of the bottom of the carb looking into the upper float chamber – see the arrow at the bottom pointing into a large hole? That’s the float chamber vent. In some bizarre law of physics that follow the same laws as coat-hanger reproduction and socks always being odd, grass seeds accumulate in this part of the AG200 carb. Don’t ask me how they get there but they do!

Now onto the smaller components. With or without an ultrasonic cleaner, you now need to focus on the brass jets. They are the heart of the fuel metering function of the carby so they have to be spotless for it to function correctly. Clean all the brass jets until no more crud comes off them onto your clean rags. Soak them like I recommended for the body above.

Needle&emultion2Take a close look at your emulsion tube and look for the sixteen small holes (1) in the body of it and make sure they are all clean. Use the four holes on one side to line up with the four on the opposite side – light needs to shine through all eight. Have a real good look at the top of the tube (2) where the needle goes in and if you see any wear or elongation of the brass, replace the emulsion tube and needle as a set. Have a good look at the needle’s taper particularly at the upper end (3) and again, if wear is present replace the set as stated.

I probably should of left this to the next part of “inspection and assembly”, but like the rubber diaphragm mentioned in my last post, if you don’t want to pay the money for parts then this is the time you stop working on your carb and start looking for another one to clean up. The bike will run like a dog with these parts worn, and no amount of carb tinkering will get it to run right until you replace them.

needle valve+filterThe fuel needle valve is next…was it leaking fuel before you valve cleanstripped the carb? If it was, don’t chuck it out just yet. The rubber on the tip of the needle is very robust and I would suspect the valve body myself. This is a problem area on the AG200 because there is a filter gauze on top of the valve that you would of seen when you pulled it out of the main body. Without a proper fuel filter, anything that gets past the tank filter will accumulate here and can make a bit of a mess. Gently pry the filter off the top of the valve and soak the whole thing in cleaner or put it back in valve clean2the ultrasonic bath if real bad. Remove the O-ring if it hasn’t already disintegrated. I have found that sticking a cotton bud soaked in carb cleaner and rotate it in the needle side of the valve will nearly always get it working again. Physical wear is not really an issue with these valves because it’s rubber Vs brass, and the rubber is pretty tough. Corrosion is nearly always the culprit and once hit with some chemicals they nearly always work well again.

Soak the pilot, pilot air, and main jets in cleaner and blow them out. Make sure you can see through their metering holes and that there are no obstructions. misc partsDon’t go sticking things in the jet’s metering holes if they are blocked, be patient and soak them in cleaner and use compressed air – it will shift the deposits eventually. Don’t forget other brass bits like the throttle butterfly, choke plunger, pilot air screw adjuster and get them as clean as your persistence and patience will allow!

Carb bitsFor all the other parts, I suggest a brush over with the brass brush to clean them up. Bits like screws and their threads clean up well with a bit of a brush up. Try and keep carby cleaner off rubber parts like O-rings and the slide diaphragm. They don’t like it but it evaporates pretty fast so don’t get too concerned. Most of the small O-rings like on the choke plunger bolt, needle valve and on the pilot air screw adjuster will probably be stuffed, but I will discuss all this in part 3.

For now we are pretty much done with the clean. I didn’t get too detailed – it’s all common sense really. Just get things as clean as you can and blow it all out and you will be done. Next we will cover re-assembly and what to look out for and some other tips.

Cheers

AGman

Carb servicing part 2 – disassembly

Now we have the carburettor out of the bike we need a nice clean work area. Some nice clean rags and a work space where small bits can’t get lost or roll off the bench. We also come to a dilemma in my normal, cheap-as-chips servicing guides – I use an ultrasonic cleaner to clean my carbs. Not that ultrasonic cleaners are that expensive these days, but I can understand if someone didn’t want to spring for one just to do a single AG200 carby.

After years of doing it with the basics, like carby cleaner and compressed air, I found that with AG bikes, the neglect has usually been severe. The built up crud from around twenty thousand ag-kilometers (equivalent to one hundred thousand normal Kms 🙂 ), and then getting chucked in the shed for 10+ years to let corrosion and old fuel do their work…well, sometimes carby cleaner isn’t enough.

It all depends on the condition of the carb. If the bike is running and is not too old then a bit of compressed air and carb cleaner may do the trick, but so many times I’ve had to remove the carb multiple times to get it right. I will admit though that was always with bikes that were really bad. What I like with ultrasonics is that you get it right every time. Its very effective when the carby is fully disassembled.

So all I can do is roll on here and show you how I do it and I suggest you get yourself a can of carby cleaner and access to compressed air if you want to do it without ultrasonics. Carby cleaner will still work well if you disassemble the carb like I do here and clean it all out and make sure any varnish, dirt and corrosion is removed. It may take a bit longer and you might have to be a bit more observant on your results but in the end you will get the same thing – a nice clean carb that works the way it was supposed to when it left Yamaha.

Throttle slide cover
Top cover

I will make a quick mention about tools; I have already done a post on JIS screwdrivers, you can get by without them and good quality screwdrivers (especially European ones) seem to fit reasonably well – just be careful and observant. If the driver doesn’t fit nice then try another. Screwdrivers for the slotted heads on the jets are a different story. Don’t tolerate a poor fit here; they are made of brass and there is a good chance they are effected by corrosion, varnish and/or caked on sediment. You will only get one chance with these jets. If you hack the slot on them you will be in a whole world of pain trying to get them out.

Slide
Slide

OK, the first thing to do is remove the top throttle slide/diaphragm cover. It pays to check this first because if the rubber diaphragm is split or torn then you need a new one and if you don’t want to pay for the Yamaha part then there is no point going on with the clean. So remove the four screws and remove the pressed steel diaphragm cap and slide spring. Slide the throttle slide and diaphragm assembly out and inspect the rubber closely. If it looks OK, store the assembly so it isn’t placing any weight on the diaphragm.

Needle bits
Needle bits

If all is good then you can proceed to disassemble the slide/needle assembly. Look down the top of the slide and you will see two Philips screws holding a metal plate. Have your wits about you when you remove the screws because there is a spring under it. Don’t get too stressed about how it all goes together because I will show all that in the re-assembly blog that’s to come, just make sure its all in bits so you can clean it up good. It also might be a good time to inspect the needle and take note of any wear because it will be helpful in diagnosing any running problems later on when its all back together. Cleaning will only do so much on the AG200, if the needle and emulsion tube are worn, the bike wont run well and you will have to replace them as a set. I will cover this after this series on carb cleaning.

Misc. bits
Misc. bits

Time to remove miscellaneous bits off the carb body now. Start with the three hoses if they are there – the fuel line, bowl drain and float chamber vent. Remove the idle control adjuster and spring and the throttle cable holder bracket.

Top jetsNow we turn our attention to the top of the carburettor. The picture to the left shows the pilot air jet (1) and the pilot  screw (2). If they look like they have corrosion issues (especially the jet) then a squirt of your fav. penetrate and a cup of coffee might be what you need! Otherwise just unscrew them and put them aside. Just be aware of the spring under the pilot screw when you remove it and down underneath that spring will be a steel washer and under that a tiny o’ring. These parts are tiny and like to flick away onto the floor or in other dark places never to be seen again so be on guard!

bowlNow we have a nice flat surface to stand the carb on the bench upside down so we can concentrate on the float and underside parts of the carby. Remove the float bowl drain screw first then the four Philips screws holding the bowl on. Remove the bowl and you should be greeted with something similar to as shown here on the right.

carb underside

A bit of a look in the bottom of the float bowl will tell you (if you don’t already know!) what sort of a battle you will be up against with the rest of the carb. Is there corrosion or just varnish or neither? While you are looking, remove the plastic shroud from around the main jet and the rubber plug from the pilot jet tube and the bowl gasket and put them aside.

Float removalGet yourself a fine pin punch and lightly tap out the float pivot Needle valveand remove the float and the needle from the needle valve assembly. I have read so many horror stories about Mikunis and their float pivot post breakages. I have never found one in an AG200 to be that tight that it causes issues, but be careful with it and if tight, relive pressure on the post by laying it on a solid surface. A single Philips screw fastens the bracket that holds the rest of the needle valve assembly into the body of the carb. Sometimes the needle valve needs a bit of persuasion to come out because of the rubbish that can accumulate on the filter on the other end of the valve, a bit of penetrant to soak down onto the o’ring can help things out here.

Remove emulsionTake a look down the pilot jet tube and see how bad it is down there. If there is a lot of crud, try to get as much of it out as you can before attempting to remove the pilot jet. Some carby cleaner and compressed air should do the job. When you have it as clean as you can, put a good fitting slotted screwdriver down there and undo the jet. Now do the same to the main jet using a larger slotted driver and also remove the brass washer under the jet. After you have done this I use something plastic like a cheap pen case to tap the emulsion tube out through the top of the carburettor.

Now we could end it here and say the disassembly is complete and cleaning can commence, but I will give the reader the option of removing the throttle butterfly and shaft assembly. I often wonder if Yamaha ever expect it to be removed with the pressed on cap over the end of the shaft, but if the job is to be done properly then it should be removed and cleaned up. Having said this, I have left in place to do cleans where the carb is in pretty good condition. There are no air or fuel passages involved with theses parts so If the bike doesn’t run correctly it will be related to another area of the carburettor. I will leave it up to the reader on what they want to do but I will document the procedure below.

Shaft capIf you look closely at the photo at left you will see where I have the screwdriver placed to lever off the shaft cover. There is a nib in the alloy casting of the carb that will allow you to use as aShaft E clip fulcrum of sorts to lever the cap off. under the cap is an E clip that can be removed along with a fibre or plastic washer. There are rubber seals at each end of the shaft that fit into the carb casting, keep an eye on them. If they don’t want to come out while the shaft is still in place then leave them until you slide it out.

ButterflyFor the shaft to slide out, we now need to remove the two Philips screws holding the butterfly to the shaft. The brass butterfly plate passes through a slot in the shaft and is a pretty tight fit soThrottle shaft be patient removing it so you don’t damage (especially the edges) it. Take note of its orientation to make it easier for you to re-assemble. Be careful the return spring doesn’t skewer you when you slide the shaft out and watch for the seal on the spring side of the shaft.

bitsThat’s it! Full disassembly is complete. We now have a heap of bits ready for the ultrasonic bath or the contents of a carby cleaner can! My next instalment will go through how to clean it all up.

Cheers

AGman