I am working on a friends twin shock ty250, 74?....

It shifts ok when cold but when hot it will only shift up and not down!!!

Any help...

If any one can send the trans. pic from a manual That Would Be Great!

Edited April 3, 200818 yr by bigspider

Sometimes the peg that locates the gear return spring gets damaged if the gear lever sustains a very hard impact, so it might be a good idea to take off the clutch cover and have a look.

I have not split the case but other that that I have had it all apart.

Engine is on the table...

The spring/s look good, old but functioning.

I think it may be clutch plate thickness but I don't know how thick the metal or fibers should be.

The bike was purchased receintly and with some fixing needed. My point is I'm not sure of the extent of second hand parts...

Check the crankcase where gear box return spring is fitted to, as this area sometimes cracks. Also before spittling cases make sure the gear change shaft is perfectly straight, by checking it in v blocks, using dial gauge.

Thanks for the response!

Yes that area had cracked, however it has been repaired to a good condition. The shaft is new and only has about an hour on it...

The gear box sounds good and spins smooth, but when the bike runs the clutch has lots of noise... I hear this normal.

I ride later model street bikes so I am not used to these sounds from a clutch.. LOL...

If its been repaired you will need to check very carefully if the pin that screws into the area thats been repaired is in exactly the right position, as if its not, then gear shifts either up or down may well be difficult/impossible due to pin restrictling gear change mechanism travel. Effectively if the pin is not at 90 degrees exactly to the face of steel rule placed across the clutch cover gasket faces at 12 and 6 oclock, then thats very likely the cause of the problem and can be sorted relatively easily.