KX 125 Main Bearings

Rikster

Member
Mar 22, 2010
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0
KX 125 Main Bearings *Need more help* :(

Hi
I tried to remove to main bearings but when i pressed the crank out, both main bearings were stuck on the crankshaft. Anyone know how to remove them? I dont have any specialist equipment and were going to try putting it in the oven then pry them off, but not sure it'l make a difference :/ thanks.
 
Last edited:

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
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It won't do much good to heat the whole crank in an oven since it will cause the whole crank to expand instead of just the bearing. Use a torch and heat just the bearing, being careful to keep the flame away from the crank. This will expand the bearing and make it easier to remove. It's best to use the proper tool which is a wedge shaped clamp that goes under the bearing and lifts it up. If you don't have the proper tool, you can sometimes use small pry bars on either side of the bearing to lift the bearing off of the crank after heating the bearing.
 

Rikster

Member
Mar 22, 2010
22
0

Thanks. I went to my friends house who had that wedge shaped clamp you were talking about which got it off.
 

Rikster

Member
Mar 22, 2010
22
0
whenfoxforks-ruled said:
How worn is the bore, where the bearing should normally ride in the cases?
Click to expand...

Tbh they are pretty badly worn. When I was installing the new bearings, they litterally fell in. I can also push them back out with a bit of pressure with my hands.

I have another problem now though. When I installed the crank, I don't know how this happened but the right bearings have gone in further than the left, so the crank scrapes on the side of the case. I have no idea what to do now. :bang: Any help appreciated.
 

whenfoxforks-ruled

Old MX Racer
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Oct 19, 2006
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Merrillville,Indiana
The bearings/seals should be flush, to the case. The crank needs to be centered between the cases, about dead on. You should be able to take a dead blow, or a piece of wood and hammer, strike the end of the crank, and move it to center. The bearings and seals can not block the fuel passages from the transfers, much less move freely. There is no accurate method to fix this, or jury rig that will hold up well on that engine, that I know of. What year is this?
 

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
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Sounds like your bearing bosses are worn out or you may have the wrong bearings. With the proper bearings the crank should center itself. The bearings should bottom out against the bottom of the bearing bosses. If the bearing bosses are damaged or excessivly worn, (Spun bearing) or the bearings are too thin (Wrong bearing) then, the crank may hit the side of the case.

You may want to take it back apart and have a shop take a look at it. If the cases are slightly worn, you can sometimes fix that with locktite Stud and Bearing mount. If the cases are excessivly worn the cases need to be replaced. Sometimes you can machine a steel sleeve to take up the slack in the bearing boss.
 

Rikster

Member
Mar 22, 2010
22
0
Thanks everyone for the help. Turns out the left bearings weren't fully pressed on the crank. It just needed a bit more motivation now its sitting flush with the case and its centered Crank spins freely nicely :D
 
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