I think that my TY250S has the wrong air restricting mixture screw in the carburettor, can someone please measure theirs and tell me what length the shaft, excluding the screw head, should be.

Thanks.

P.S. Can someone please tell me what size main jets they're running, apart from the standard 145?

I have also just found that my bike runs with the mixture screw removed, any ideas as to why or do they all do this?

Sounds like something is stopped up. I would suggest blasting out the hole with some carb cleaner the try it. If that dosn't work then pull the carb apart and give it a proper cleaning. Lots of small holes and orfices that must be open to work right. Pretty easy job to do.

Cheers I'll give that a try.

I had a similar problem with my TY which turned out to be an air leak, either between the rubber manifold and the barrel or the carb and the rubber manifold. I don't know which one because I silcone sealed both areas at the same time and it fixed it.

Thanks to all who have replied, I have almost sorted it now, a small peice of fluff was blocking one of the three small holes in the back of the carb, but it still runs rich, any other ideas? trying a new pilot jet as this one has no numbers on it, does anyoe use a different from standard piolt jet? the standard is #42 according to the manual...

You could riase the clip on the needle to lean it out some or, if you are still messing with the origional TK, pull it off and get a Mikuni. I don't think you can find any jets for the TK. I swapped and mine runs great since changing it out. My old TK would never hold a setting. It was just worn out.

what Mik did you use? was it a mono?

I put a B&J Mik on a twin shock 250, worked great especially compared to the worn out TK. Like to tdo the same on my mono 350.

kcj

The clip on the needle is already on its lowest setting, almost solved the problem now, its still running rich but after a whole days riding the plug did have some oil on it but no black soot, I'll keep on eye out for a Mik carb though, but I'll only get one if its the right price, the TK carb seems to be hardly worn. That said though it has had a re-bore, little end, big-end, crank seals and a gear box rebuild to try and solve the problem, although the gear box rebuild was to put in new selector forks, so I know that it can't be burning its oil.

It seems to oil its pug up worse when its muddy and slippy so I'm only using small throttle openings, this is why i think it might have the wrong pilot jet, so I'll try to find a new one!

Thanks to all that have helped.

I am now running it with three turns out on the mixture screw, seems to have done the trick! still seems a bit oily though so any help most welcome...

its taken a while so far, over a year in fact so any help is highly appreciated!