looks like a seal of sorts in the oil pump in the pic where it must seal into the cover to go wherever it goes--crank or filter housing, but an important little Oring or flat seal. Long time since i've been in one of those. Did the bigend & mains on an SR250 once which is much the same with a couple of mm smaller bore. No idea why they did that & had something like 230cc on the base of the cylinder. Seemed like a silly idea unless there was some tax saving for 230cc compared to 249cc, i dunno.

Pretty much finished up the XT200 this week. Took more work and money then the XT250. Besides the normal maintenance performed like on the 250 this bike had a leaking fork seal, kickshaft seal and needed a new fuel petcock and rear sprocket. Last owner installed a new chain but left the worn rear sprocket? Maybe because it shows discontinued thru Yamaha or he just didn't want to spend the extra money? My local dealership came thru again. Had a sunstar steel silver 47t rear sprocket in stock. He cross checked the kick shaft seal and had it in stock too.

Biggest issue with this bike was the carburetor. I have rebuilt or rejetted 100's of carburetors over the past 30+ years and never came across one of these or at least don't remember it. Yamaha uses a Teikei Y24P carb on these bikes and apparently used this brand on many other model bikes in the 80's and on up?

Talk about thinking outside the box when dealing with one of these. 1st problem is there are no parts thru Yamaha for different jetting or even stock. 2nd issue is there is no adjustments to be had if you wanted to dial in jetting or fix a running issue? The needle has no grooves to pick from, its spring loaded in the slide. No adjustments, Air mixture is sealed off and has no set spec's. This one has been unsealed thankfully. No pilot or main jets available stock, up or down in sizes. Float has no tang to bend for adjusting float level. Needle & seat are different then anything i seen but it is available thru Yamaha at a very high price!
Luckily i was able to find a NOS stock size pilot jet on e-bay in the yamaha sealed package. Bowl gasket and all o-rings i was able to get thru Yamaha.

To get this carburetor to work right it has to be in super clean condition and the float level has to be spot on. I mean spot on. It's very critical on this carburetor. And to check it you have to have the bike running with a clear tube connected to the port in the bottom of the carb then a larger 6mm ID clear tube connected to it and bring it up along the carb body then you check or measure where the gas is in the clear line compared to the float bowl body. You do this by loosening the screw in the bowl. Fuel level needs to be 3.5mm below bowl/carb body line. Bike has to be perfectly level when doing this. This is not a easy task just to get a correct float level! If you don't get it right the carb has to come off everytime. This one was at 6mm 2.5mm low when i bought it. Then like i said there is really no adjustment on the float tang? I had to really be careful when bending the floats on each side to try to get enough bend to get the float level higher. I was finally able to get it correct and the bike starts, idles and runs great. Before it was cold blooded, it had a flat spot right off idle, when cruising with a steady throttle you couldn't just roll the throttle on without a good hesitation and you could hear some small backfiring thru the muffler during deceleration. However full throttle was no problem? Go figure. All this disappeared when i got the float engine running level correct. I ended up adjusting the fuel mixture screw 2 1/4 turns out.

Not sure why Yamaha decided to use these carburetors and not Mikuni but my guess is cost and emissions? No adjustments means people can't mess with them. I must admit the bike does start and run great now and really needs no adjustments once it's clean and dialed in.

Wonder how this bike compares to the 80-81 DT175's? This bike seams to have plenty of get up and go even with my 235 lbs on it. Like the 250 it has plenty of torque right off idle all the way up thru the rpm and rev's out nice. Wish it had a tachometer so i could see what the rpm is when the power runs out on top end. Nice play bike for sure. Light, plenty of get up and go. Super easy clutch feel and smooth as it can be. Suspension much better then the older bikes from the 70's. I adjusted the preload a little stiffer on the monoshock but when i redid the oil in the forks i used 10wt as the service manual says but i wish i would have used 15wt for a little firmer feel. There plush but a little soft for my taste or riding style. It would be perfect for a lighter rider as there is plenty of travel front and rear.

Here are some pics of the TK carburetor and the bike. Only thing i refinished was the exhaust pipe and engine guard under the bike.

Skydancer wow that’s the way you adjust the float on a Model A ford yes it’s a pain to do the first time wasn’t any fun but I took some measurements to simplify it if there’s a next time. You bike looks great!

HT1KID,

Yes i have seen this method on some other applications including the XT250 but it has a Mikuni carburetor. I didn't expect a TK carburetor on this bike?  Yamaha does provide a "float height" spec in the service manual which i assume gets it close when you have the carburetor apart. I did set that but it still wasn't good until i was able to get a 3.5mm drop level with the engine running. Then all running issue's went away. It also states 3.5 +/- 1mm for float level but even at 4.5 it didn't start or run as good as when i finally set it to 3.5mm. Very finicky carb.

The other big issue as mentioned earlier is the float and valve seat set. You can adjust the tang to lower the float a bit but there is no adjustment per say to raise the float level. I had to bend the float arms to each float to get it to raise. Believe me the float isn't level with the carb bowl surface like most carbs either! It's on a steep angle up most likely due to the needle valve seat design. I was reading in the XT forums on other sites where guys were actually removing the thick red colored washer under the valve seat to get the float higher. I wasn't going to do that. 

I guess in the end it's actually the best way to set the float level because your really are seeing the exact float level as the engine is running. Turn the gas off while it's running and watch it slowly drop as it runs out of fuel. 

The XT250 is the same way for setting the float level "but" has a Mikuni VM28SS carburetor so the float and needle valve assembly is more your standard design and is easy adjustable. Plus the float sits at your standard level position when apart. I didn't have to mess with it after setting the "float height" as per manual. 

Thanks for the comments! 

Wow your XT turned out great!  I have owned an 83 XT250 for 15+ years, not the best dirt bike or street bike but what an amazing machine, just a simple and fun bike!  

Oldbikenut,

Thanks for the comments and yes i agree, Very simple and fun bikes to ride! 

That 200 looks great, I don't think I've ever seen one that wasn't totally clapped out. Compelling bike for the simplicity and light weight, I wish the new XT250 was in that range instead of the rather porky 291lbs it is.

Darinm,
I didn't realize the newer XT250 were that heavy. Yamaha claims this XT200 at 216 lbs dry weight and it could very well be. It feels much lighter then it's bigger brother the XT250 for the same year. For just a mer 50cc these bikes are completely different in everyway. I agree most of these bikes are destroyed or parts bikes. When i seen these 2 i was in shock of there condition here in upper lower Michigan. I keep thinking there newer bikes as i am used to early 70's Enduro's but there still over 40 years old! 

They came with all the owners, service manuals tool kits and brochure with dealer stamp where they were bought new. Looks like they been together since new and were bought as a pair and owned by the same  owner. Most likely used as a weekend pleasure bike here in Michigan. Must have been stored in a nice dry garage for being in this condition.

thanks 

 

Incredible find, congratulations on the pair and good to hear they run well after all that carb work!

For whatever reason to get in that weight range today it's expensive, Beta Xtrainer 300 two stroke is $8400 and the same weight.

Quite astonishing condition.  What a rare find.

So far as weight is concerned, important to note that back in the day, bikes were quoted as dry weight.  That is no fuel, no oil in the engine, forks, rear shocks and even devoid of battery acid and brake fluid.

During the 70s the Japanese were famous for shaving 50 grammes off the next model year and almost as famous for hand assembling the bike for weighing using hand selected, pre weighed components.  Just as they were famous for being a little " over enthusiastic" assembling engines when quoting general power ouputs.
Put these together and voila!
We have the press fleet............ Until some nosey hack took one apart and the scandal of hand finished ports ect was discovered.  Seem to recall the Kawasaki GPZ550 being the press bike that possibly brought it all to light in the early 80s and it may have been Motorcycle Mechanics magazine that did it.  A simple comparison between a showroom model and the press model port finish.

These days, quoted weight is wet.  All fuels and fluids.  That can add 50lbs + depending on the bike.