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Hey guys iv been rebuild the bottom end of my kdx 200 and its time to install crank bearings and seals. My question is, what is the best method for install them? The seal has to go in first then the bearing so I was thinking that I couldn't sweat it in because I might melt the seal.

Cheers for any help.


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im sure its not what you want to hear but thats one thing you want done perfect. it can cause a whole heap of problems if not done correctly. Im all about doing it yourself but i would encourage anyone to have those pressed in by a pro with all the correct tools.

The freezer / oven method has always worked for me.

Tedh98 wrote:The freezer / oven method has always worked for me.

Cheers ill try that.


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Just keep the oven temp at 200 and the seals will be fine.

I have had good luck protecting the seals by covering the exposed portions with grease.keeping oven at 200 deg and using an infra-red thermometer to monitor temp of case halves.when case hits 200 pull it out and frozen bearing will drop right in.do a leak down test once case halves and top end re assembled but before installing clutch.should hold 7 psi overnight.

Thanks ill do that ^^.


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If you use a press make sure to press on the inner race only of the bearings can potentially cause damage if you don't

nab wrote:If you use a press make sure to press on the inner race only of the bearings can potentially cause damage if you don't

If you are pressing into the case you wabt to press on the outer race. If you sre pulling the crank thru the bearing then you want to support the inner race.

You just never want to sideload the rollers.

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Yeah I do have a crank puller so ill use that for the left half case at final assembly. Iv decided to pre heat the case halves in the oven at 160oC then drop the frozen bearings and crank in. Should go pretty smoothly, just have to wait until my crank comes back from the machine shop.


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160C is about 320F, don't know that I'd go that hot (except to make chocolate chip cookies )...maybe closer to 90C...it doesn't take a whole lot of heat if you freeze the bearings for an hour or so.

bufftester wrote:160C is about 320F, don't know that I'd go that hot (except to make chocolate chip cookies )...maybe closer to 90C...it doesn't take a whole lot of heat if you freeze the bearings for an hour or so.

Oh thanks mate. I think I was getting confused with oF .

I have to wait at least 2 weeks now anyway to get my crank back from the engineers before I can start fitting things back together.




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Installed crank with a bit of trouble. Took two attempts with the heat freeze method because I didn't get the bearings hot enough. Second time round it just dropped right in with a clunk.

Used the tusk crank puller and put the cases back together with ease. Had to give the clutch side crank end a hit with a soft blow hammer to allow crank to spin more freely.

Question: I put in a brand new piston which now has a few rides on it. Should I put it back in with the new bottom end or should I put in a brand new piston again?


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How many rides is "a few"?
How many hours on it?
What does the piston measure?
What does the bore measure?

Not that you can't reuse parts, but you should be as informed as possible on its condition before doing so.

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adam728 wrote:How many rides is "a few"?
How many hours on it?
What does the piston measure?
What does the bore measure?

Not that you can't reuse parts, but you should be as informed as possible on its condition before doing so.

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It has about 6 or 7 rides on it. So about 7-10 hours of use.

Not sure on the measurements but I wouldn't think that little use would have worn the piston and rings out.