tranny problem, 125 jumps out of gear

[moron]

when going from 3rd in to 4th my bike either goes back into 3rd or hits neutral, if I slow right down in 3rd then go to 4th it stays in gear and can go up in 5/6 gear.
thanks in advance
steve

[KX500freak]

 almost certain the dogs on the sprockets of the 3rd gear i would say
if they wear this accures
sure needs to be further looked in to .
and i can tell by own experience
it can be an expensive repair,if bearings and axles got banged up to much

[moron]

thanks for the reply kx500freak, I am splitting the cases tomorrow and will check for signs of wear
cheers, steve

[KX500freak]

cheers moron...grtzz idiot ,funny connection here hahah..

keep an eye on the shifters fork ,if worn it pushes not the complete distance butt less
then also 3rd is not engaged fully 

[moron]

Split the cases and stripped the transmission and found the dog holes on the 4th gear worn and also the shift fork for 3/4 gear is warn and bent. so all in all an easy fix thankfully.
steve

[KX500freak]

nice job.

i,m impressed ,got any pics made during the event

[moron]

No, but can shoot some if you would like.

[KX500freak]

if it,s not to much trouble ,it would be great .
not just for me,allthough i,m working on a tranny also,but for all
a pic of the fork ,the dogholes worn .
thnx

[moron]

Here we go

[KX500freak]

AAaarggh 

i,m looking at exact the same kind of fork in my tranny..
i know now what happened too ..
and for the dogs/holes ,same story
make sure you replace both in a set.
thanks for posting steve

pic is my tranny ..3rd gear ..same issue as you 

[moron]

The annoying thing is I had the cases in half not long ago when I replaced every bearing and seal but didn't spot this problem.
Just goes to show that when ever you get a chance to check the internals you should.
steve

[holeshothirons]

Hi, I am about to sort the transmission on my 1992 KX500 next week, it runs fine up to and including third gear then it just feels like a false neutral. I have raced the bike locally in the UK all year like this and not really missed fourth [I must be slow]Hopefully when |I strip it down I will find whats wrong god luck with yours.

[moron]

Just thought I would update on progress, I purchased new 3rd and 4th gear cog (not cheap), and new shifter forks and also the spring on the gear change shifter as it was stretched slightly, put back together and all is well problem sorted.
steve