This weekend while racing my 87 250r I came off a decent sized jump and when I landed (with the the throttle on) the tranny acted up. It will move under its own power till 1/4 throttle but after that the tranny slips and grinds. I was hoping it was only the clutch but I inspected it and it is fine. Now I noticed that the seal around the countershaft is leaking (heavily). I am thinking i wasted the countershaft and was wondering if anyone else has ever had a problem like this. I have had 2 other 250R's and never had any tranny problems

 

The countreshaft is a beefy piece. Here's a few possibilities.

Bent shift fork holding a gear near a false neutral, the gear hasn't fully engaged into the other gear. There are three different gears that slide back and forth via the shift forks, engaging and driving from the main shaft onto the countershaft.

You may have had a bearing fail. With it leaking around the countershaft as well, the countershaft bearing may have went.

Broken gear. Maybe not a clear fracture of an entire gear, but possibly broken, missing teeth.

It's amazing that there isn't more problems with these trannies considering how most of us treat them.

2nd gear on the countershaft is prone to complete failure. Puts a nifty skylight into your cases most times it breaks.

I'm down right now for just that reason. I'm having my complete transmission cyrogenically tempered. We'll see how that works. Also I noticed that the gears themselves weren't finished all that well. There's alot of sharp corners that could benefit from having a radius ground to help prevent stress risers.

 

thanks. Ive decided to send the whole engine over to a local reputale shop and let them deal with it. Seems like I never have any spare time anymore and they can do it faster