Help. Rear wheel/tranny kx80 locked

1998 Kx80. Owned for about a month. Ran fine until today.

2nd gear, trail riding, 13 year old rider(gf's kid) in front of me, rear tire locks up, slide/skidding to a stop.

"what's up?" i ask. "Dunno. I think the brakes are stuck?"....

Turns out, clutch in, or out, the motor/tranny won't let the chain or rear wheel turn.

For basic diagnostics, I pulled the chain: Rear wheel free wheels fine, and the rear brake works fine and doesn't stick.

Chain back on, bike in first, clutch in: wheel locked (chain goes taught when pushing bike, wheel won't turn.

bike in nuetral (I think... can't be sure, as the rear wheel/front sprocket is STILL locked) same results...

Tried that in all gears with the same result.... I ended up having to carry the rear end and walking the bike about 2 miles... good GOD am I gettin gold... you'd have thought I carried a 200lb man several miles instead of 1/2 of a 120-is lb bike!!!

Since we've owned it, it's been a little hard to get into nuetral once it warms up.... but I've had lots of bikes like that over the years....

ANy ideas? I'm thinking it obviously has to be a tranny issue, as it starts and runs fine... until you put it in gear and let the clutch out....



Maybe it is the trans but I have seen the lower rod bearing lock up the motor and act like this. You can't get it to shift because the gears are not turning to go into each other. Try bumping the bike backwards a few times and see if it unsticks. Sometimes the rollers in the rod bearing flatten and then roll like a sprag clutch and the more foward you go the tighter it gets and a little bump backwards frees it up . This may not be your problem but I have seen this many more times than the trans causing this.


Sorry. just reread you post and now see that it runs fine, my bad. Must be the trans and now it is time to split the cases. Good luck


Dang. That's about what I figured.

In 37 years of riding, I've never split the cases for a problem. Done it to do some mods/upgrades, but never for repairs....

Well, thank god I have a job w/lots and lots of free time :thumbsup:

rmantoo you may want to search my threads, a while back I put up 2 that have a lot of pics on splitting and reassy a KX250. These may be helpful too you.


I would pull the right side case cover and check the shift mechanism first. Always start with the simple things first. Could be something bent or jammed.

I always tell my son, "Working on them is half the fun."

Good luck.


Just got finished pulling right side cover, and everythign tehre appears to be fine.

Started pulling the motor: pulled the exhaust, then drained the oil, then the coolant: The coolant was pretty much 50/50 mix of brown water and sludge!

Pulled the carb/airbox, and then broke 2 12mm craftsman sockets on the engine mounts, and then broke a 12mm wrench, too!

Off to the hardware store.... IMPACT sockets, YEAH BABY!

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