Jump to content

Confirm my fears. Crank Bearing?

Recommended Posts

I am doing some work for my sons buddy from college who's bike "wouldn't run"....... (Not sure how I always get roped into this kind of stuff)

Bike is a 05 CRF250R

When he asked me to look at it he told me that he couldn't get it to run. I picked up the bike and got it home. When you kicked it over, you could feel it dragging/grinding a bit.... I called and he said that he had done a top end on it recently. My first thought was a messed up ring.

Well I got the bike apart and the top end looks good (head and cylinder are off). When you try and turn it over with the kick start by hand, the crank gets to the bottom of the stroke and it stops. I put the bike in gear and you can turn the rear wheel in reverse "freely". When you turn the rear wheel forward, it gets to the bottom of the stroke and stops.

My first thought is crank bearing but why would it turn in "reverse" so easily?

  • Like 1

Share this post


Link to post
Share on other sites

That'd be a new one for me.  I'd probably try to take the clutch side cover off and undo the nut off the crank end and take both primary drive and counter balancer gears off (or shift 'em so they don't engage, don't remember if you can take them off with the clutch basket still on).  If that frees the crank up then maybe it snags in the counter balancer, easy to test putting the gear back on.  If that doesn't do it take the flywheel off as well (need a puller), and then if it still snags that'd be something with the crank itself.  But sounds strange, if you don't feel the rod snagging anywhere, and there's no junk in the cases for the crank to rub to, I don't see the crank bearings only getting stuck in one specific position.

I'm assuming you checked the rod for play and the crank itself doesn't have any detectable up/down play.

Edited by dakh

Share this post


Link to post
Share on other sites

Thanks dakh,
Good idea. I'll give that a try in the morning. I didn't check the rod play yet... it moves freely however. It seemed odd that the bearings would drag only in one spot/direction. I'll pull clutch side first then flywheel tomorrow.

I'll let you know what I find....

Share this post


Link to post
Share on other sites

Id pull the clutch cover off and check things out. Then pull the clutch basket off to seperate the crank from the transmission. From there you can see if your issue is in the crank, or in the transmission.

I just rebuilt an 05/06 from the ground up. If you need a brain to pick, don't hesitate to ask

Edited by AlotL1keVegas

Share this post


Link to post
Share on other sites

Thanks guys!

I took the clutch basket off.... That side was fine. The crank was still dragging and not turning smooth. 

Took the flywheel off and timing chain out and the crank spins free as can be. I think the timing chain was binding up as it went around the crank. Not sure how it was sticking in there but you could sure feel it when it was all together. You could even hear it when you kicked it over with the plug out. There is a small chip out of the timing chain guide pocket. (see attached). Don't think it will hurt anything. 

The kids had done a new top end before it stoped running. Perhaps the cam chain wasn't reinstalled right, got messed up in there and it skipped a tooth, thats why it stopped running. Anyway, new chain and some gaskets and I think we are good to go. Not to pricey. I can't imagine trying to finance this hobby while in college.

 

IMG_3256.JPG

Share this post


Link to post
Share on other sites

Don't think the chip in the case will hurt. But I would double check to make sure that that piece isn't inside some where. From what I see in the pic, it looks like a fresh break.

Edited by AlotL1keVegas

Share this post


Link to post
Share on other sites

I found a small piece. Not the whole thing. It is a fresh shiny break. When I drained the oil, it looked clean like it had just been changed. My have run out. Ill look more. The screen (one in the picture) was clear. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×