lower end of 86 big red

[daniel boone]

I have not had 2nd gear for sometime in the big red. When you hit 2nd it would jump, grind, and sound like skipping gears. Opened it up over the weekend thinking it would be obvious what was wrong. Well every thing looks good. I still have to mic. every thing to check tolerance, but the problem is not obvious. The shifting forks look straight, and the gears show little to no ware.
Any idea what it could be?
Keep in mind that I work in a machine shop and cut gears all the time so I do know what gears are suppose to look like.
:D

[likestrikes]

You have just described my 250SX to a T!! It had no first gear and ground when I put it in nuetral or first. Tore it down and gears were fine - some rounding of their engagement slots. However The shift drum itself had some of there peak spots worn down to a flat. I assume this leads to partial engagement of the gear and the grind and noises we hear. Check you cam drum and the fork pins that ride in it. Please let me know how you make out.

[daniel boone]

thanks! I'll check it out and let you know.:)

[Kryten]

I have got about the same problem on my 200X. First gear will only engage about half the time. Have not torn mine down yet though. Sounds like the problem is not easy to diagnose.

[likestrikes]

I dunno, maybe it's that fear of transmissions I have, LOL. But honestly my shift drum should be the culprit along with the fork pins that ride in it - very obviously worn and would cause only partial engagement or partial disengagement - which would be the noise heard when it won't go anywhere. So in my case I hope the drum and forks do it but the shift raised lugs are also slightly rounded as are the once "merely deburred" engagement slots in each affected gear - may have to buy those too. I sure do not want to assemble an entire 250SX tranny only to find a problem - talking like 10 hours work.