Monthly Archives: September 2013


Before I start here, I just thought I should let you know that the info here is strictly my opinion and based on my own research. In other words it’s flawed! For a start its based on what we had imported into Australia so it could easily be a distorted view of how things really are. If anyone sees glaring holes in my theories then please, flame me! I am happy to take on more info on this motorcycle, its engine and its derivatives. So having said all this, lets jump in.

Yamaha XT200 82

In Australia, the first motorcycle to see the engine that was to migrate to the AG200 was the SR185 road bike in 1982, while the XT125/200 trail bikes made an appearance in the next model year. A bit of hunting around on the ‘net suggests that the SR125 may of made an appearance a year earlier in other markets but we got our first taste in ’82/’83. Inspection of the XT series will show a lot familiarity with the AG200. Not much modification was needed to turn the XT into an AG. In fact, if I was pushed to say what was the father of the AG200, I’d say it was the XT200.

Yamaha XT125 82  2

And here is one of my first speculations; the XT may of been the daddy of the AG200, but the bike responsible for it was the AG100/175. Why? Because of the 2 stroke emission issues. I think the Japanese could feel the pressure building on emission legislation in the early 80s in their biggest market the USA. Even though they didn’t export the AG200 to the US and probably never even considered it, I think that they felt there needed to be an alternative agricultural bike than the old smokers. And by the way, if you think the AG200 has had a good run then consider the AG100 was first released in 1973 and can still be bought brand new today!

So was the XT the start of the “commodity bike” for Yamaha? The cheap, bread and butter engine for use in multiple models for multiple countries? The models it was used in included the SR, XT, AG, TW, TTR, and the top end was used in numerous ATV variants as well. I dont know who the engineer was from Yamaha (I am looking for the answer), but I reckon they did a top job and they sure made some coin for that company!

Model – XT200K (15Y)

Year – 1983

Engine – Air cooled, 4 stroke, Single cylinder, DOHC

Capacity – 196cc

Bore/stroke – 67 x 55.7mm

Compression ratio – 9.5:1

Carburettor – Teikei Y24P

Max power – 18hp @ 8500rpm

Max torque – 1.6kg-m @ 8000rpm

Front brake – Drum

Rear Brake – Drum

Front tire – 2.75-21

Rear tire – 4.10-18

Fuel tank capacity – 7.3 Litre

Dry weight – 98kg



Latest project – shakedown!

If for some reason you think you need to get yourself a (second hand) AG200, take my advice; If you cant find a road-only ridden bike (who would buy an AG bike for road/street use?), then try and find one that has been used on a dry country farm. If the farm is irrigated then try and make sure its not dairy. Why? Because water and dirt encourages corrosion. Water, dirt and manure encourages destruction! Everything from steel, aluminium, rubber, plastic, paint, plating, anodising…you name it, it suffers under exposure to cow crud! Throw poor maintenance on top of these conditions and you get a money pit.

Project AG1

That’s why the bike shown here caught my eye when I found it at a small country dealer. It was a dry county bike with twenty thousand kms and even though the top end of the motor was tired, it was all complete and in very good condition. Dealers know what their stuff is worth so I paid good money for it but that means I don’t have to spend as much getting it into a good, reliable condition. All the standard things were covered with this bike; Rings, timing chain, swing-arm bushes, and all the other consumable wear items.

So anyway, all the work has been done (back to bare frame clean-up), and now its time to get some heat into it, stir the gearbox around a bit and then head back onto the hoist to drop the oil, inspect the oil filter, re-tension the head bolts and check the valve clearances. Hopefully after this I can do some recreation rego. and we are off to the Victorian High Country.



Drain cap destruction

Oil drain cap

The AG200 has a slightly unusual method for draining the engine oil. Instead of a generic old drain plug, it has a drain cap which is also used to hold a spring loaded oil strainer. The AG200 engine has a cool design where it has a big strainer at the bottom of the engine to hold back the big chunks, while the finer oil filter (on the other side of the engine) keeps the rest of the damaging material out of circulation. Now all we need to do is get people to clean them and replace the oil! …but I digress!

The real aim of this post is to guide people on how to not chew up the drain cap. Here is the crux of it; the hex head on the cap is 19mm, if you use a shifter you will wreck it. If you use an open end spanner you will wreck it. If you use a double hex ring spanner you will wreck it. If you use a double hex socket you will wreck it. If you use a cold chisel you will…you get the idea!

AG200 oil drain capThere is one effective way to get it off without damaging the cap – a single hex, 19mm socket. Where do I get one of those I hear you ask, drop into your local tool shop and ask for a 1/2 inch drive, 19mm impact socket. It will be black (black oxide), and have a hex interface to match the drain cap. They are cheap and make your life a lot easier as far as oil changes go.

19mm single hex



Using a decent fuel filter

Although this isn’t a specific tip for the AG200, I think it is relevant to mention it here. Like most factory internal fuel tank filters, the AG200 uses a plastic gauze which is not real effective at removing rubbish from the fuel. The generic in-line filters from motorcycle and carburetor accessory stores are barely better than nothing as well.

So think of an industry where maintenance is not on the radar…something that only tends to get looked at when it goes bang or stops running for some other reason. I’m thinking lawn mowers! They get virtually no maintenance from the average user so the motors and ancillary parts have to be basic and withstand serious neglect!

Fuel filter

So I thought I bet the fuel filters are a bit more serious than your average bike fitment, and I was right! Check out the filter in my pictures and you will see its not pretty, but that suits the AG! It has way more filtering area than the proper bike filters and the medium is finer so it will actually keep rubbish out of the carb as intended. You can see water and dirt  accumulate in them as the fuel flows from the outside into the middle, so what it filters, you can see. A great visual aid at service time.

The AG200 first made an appearance in 1984, so some of them are getting some serious age on them now. I doubt there are many still alive from this period any more, but the neglect they receive means if you do acquire one, you will have to keep on top of maintenance items like this to stop the headaches. I also think that if a decent filter was fitted from new, then maybe we wouldn’t see the emulsion tube (needle jet) wear issues that we find so common here.

filter part no

The filter that I use is a FPL5553 from GA Power Equipment Spares. Just drop into any mower shop and ask the parts guy to have a look at his filters. Maybe take your fuel line in with you to help him out a bit. Any thing with a paper element will do, the AG200 sips fuel in standard form, so the flow rate is probably less than most mowers anyway!

Remove your fuel line from the bike and you will have to remove a few centimeters from it (I take out 3cm) so it all fits neat between the tap and carb. Removing the line facilitates fitting the filter because it can be tight installing the rubber line (especially with it freshly cut) and painful while trying to do it on the bike. Some silicon lube might be helpful in this case, as can some warmth on the rubber line.

So there you go, a simple mod that will keep you happy riding without worrying about bad fuel ruining your day. Keep an eye on the rubbish in it, and you will be able to keep the fuel up to your bike and help it run reliably and hopefully avoid carby contaminate problems.