Trouble with Trannies..

[giggyhurdle]

Good afternoon..
It's been a while since I've been on.. and I've come out with a question.. My bike.. when running.. runs well.. No real issues except a.. well, a major one. My transmission is out of sync or something. N-4 cannot be used. I cannot shift the bike into neutral, because it doesn't exist. 1st-4th gear don't work, that is.. when I'm in 1st-4th and release the clutch, the wheels lock up. and when squeezing the throttle, the wheels will not move. The bike will not roll unless in 5th gear and with me holding in the clutch.

Do I need to replace the clutch or the gear box? Or both?
This happened when I had the bike warming up.. sitting idle, the bike was leaned slightly to the left.

 

[dirt bike dave]

What bike?

Could be something fairly easy to fix, like the shift shaft return spring has popped out of place.

I had that happen once, and my bike had similar symptoms (except it was stuck in 2nd or 1st instead of 5th).

To fix, I drained the trasmission fluid. Laid the bike on the left side. Popped off the right side cover. The shift shaft extends all the way through the engine, and the spring is on the right hand side.

One end of the spring has a pig tail that keeps the spring from spinning. If that falls out of place, the spring will spin. I ended up putting a washer over the shift shaft to shim the spring and help it stay in place.

Total cost was 1 quart of oil and a washer from my tool box.

 

[giggyhurdle]

75 Yamaha mx 250.

I'll take the case off and drain the fluid this weekend. With summer rolling around.. I'm excited about taking it out again.

 

[zoommx]

My best guess is that the pinion gear for 5th is siezed to the shaft.