New crank case bearing stiff

11 replies to this topic
  • volitan

Posted January 19, 2012 - 05:08 AM


I just replaced all my crankcase bearings in my 03 yz450. The bearing in the crankcase that sits in line with the clutch lever( the one that holds the clutch shaft and transmission gears.. It has a seal on the one side) is
Very stiff. I have to put my 2 fingers in the inner race to turn it. All the other ones
I can turn it with one finger. It's a new bearing and it was pressed in with a press on the outer race. It was frozen before install. Now that that bearing is at room temparutre it's very hard to turn. It's not rough or anything.

Is this normal? I'm affraid that it will overheat and seize.

Any help would be greatly appreciated.

It's an oem bearing too

  • stroker101

Posted January 19, 2012 - 05:45 AM


have you put oil on it? i have had some bearings that were a lil stiff but after applying oil to them and rotating, they loosend up

  • grayracer513

Posted January 19, 2012 - 06:33 AM


It should be free. Does the bearing have a metal shield/seal on one side, and if so which side is the seal on now?

  • volitan

Posted January 19, 2012 - 06:39 AM


The seal is on the out board side. I did
Put some oil in it but it's still stiff. It feels
Like a new wheel bearing that is sealed from the factory.

  • grayracer513

Posted January 19, 2012 - 07:34 AM


You may have the bearing inserted out of square (one of the hazards of using a press), and/or the shield may be pushed against the back of the pocket, causing it to drag on the ball cage or inner race.

  • volitan

Posted January 20, 2012 - 03:28 AM


Thanks guys.. ..for 20$ I just ordered another one instead of chancing it.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • yzfxr

Posted January 20, 2012 - 04:22 AM


I've had 3 400-426 bottom ends apart, and that bearing always takes more effort to rotate than the other bearings. I've replaced it too, thinking there was a problem, but it felt the same after. Maybe your other new bearing will feel better, but I bet it will be about the same. Like you said, it takes two fingers to turn. It's kind of like the intake cam in these bikes. Most I have dealt with, including the '03 450, will not rotate as freely as the exhaust cam (with the chain off).

  • The Spanky

Posted January 20, 2012 - 04:22 AM


Thanks guys.. ..for 20$ I just ordered another one instead of chancing it.

Very wise decision. That $20 may save you from a lot of grief later. :smirk:

  • volitan

Posted January 20, 2012 - 09:08 AM


Yes for sure.. I replaced every single bearing in the crankcase so having one failed wouldn't be too fun.. Especially 20 miles back in the trails lol

  • vet45

Posted January 24, 2012 - 05:03 PM


ive rebuilt several of these and this particular bearing is always stiff, ive actually done what your doing now, waiting on another new bearing. it will be the same. but you will have piece of mind on the next several you rebuild.

  • volitan

Posted February 01, 2012 - 08:14 AM


Thanks for your reply that gives me piece of mind now.

Is 140 hours alot for that engine? It's
Been a trail bike since new.

I'm used to sports bikes so I'm not sure what is alot on a diet bike.

  • Ricks426

Posted February 01, 2012 - 04:40 PM


If the 03's are anything like my 00 426, I have well over 300 hrs on stock motor and well over 5000 miles. They are reliable as long as you do your routine oil and air filter changes. I would still be on stock piston if I didn't have to change 2 gears in the trany....since the cases were split, I put new piston and rings.

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