04 Cr250r crank not spinning freely

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10/15/2018 8:02 AM

Help!!! I bought a low hour 04 cr250, but it's quickly turning into a nightmare.

The bike runs, I took it for a quick spin around my backyard before the tear down, all seemed ok.

But with the engine out, I found it very hard to turn over (even with the plug out, so no compression). This is to the point I have to turn the crank with a long wrench on the flywheel nut. But, even then, the crank does not spin smoothly. It is extremely "notchy", for lack of a better description. It does turn with the wrench on the flywheel nut, but I get a lot of resistance, the crack turns maybe an eighth of a rotation, then a lot of resistance again. This is with the head off, so I can see the cylinder is in good condition and no seizure at all.

What is wrong? Main bearings or crank bearings are gone?

I suspect the bike has sat a lot of its life. Maybe some moisture rusted the main bearings?

Opinions please! Thanks in advance.


10/15/2018 8:14 AM

The cause could be many things. With that kind of resistence your solution is to do a bottom end rebuild and replace bad parts you find.


10/15/2018 8:24 AM

I would remove the crank gear to see where the resistance is. So you can test interdependently where it binds.

I would also check if the crank is true