Spun Crank Bearing on Cr80?

[rennat_2006]

New to this forum but not to dirtbikes, atvs, cars, etc.

Anyways my little brothers 97 Cr80 started smoking more than normal and fouling a spark plug like every 20 minutes last time we took it out riding. It smelled like burning gear oil(running 75w90 in the trans) so when we got home i drained it out, It was filled with 14 ounces but i only got 9 ounces out so that pretty much confirmed what i figured about the crank seal leaking.

I tore the clutch cover off and took everything else off to get to the crank seal on that side and removed the seal.
Now with my KTM's(91 540 and 96 550) they use "C3" i believe they are called crank bearings which are built to have just a little bit of play in them, Just enough to feel it pretty much.
Are these honda's the same way?
It does have some up/down play if i grab the end of the crank and push/pull up and down, I looked at it more closely and it appears the bearing race on the crank has spun, I can turn the reach in and turn the race without the crank moving. This explains the up and down play also.

Hopefully we will get lucky and just the race will be damaged and not the crank! He is only 14 and sold alot of his stuff and saved up his money for this bike and bought it a couple months ago to be able to go riding with me. He is pretty bummed out that we keep having problems with it especially because he doesnt have a job to pay for parts. Im buying alot of the parts for him just to keep him riding but that isnt going to last with me putting my 96 550 back together here real shortly.

 

[Jasle]

C3 bearings are typically only good for about 3k rpm. your spinning much faster than that. I use C4's. just the smalles amount of play is acceptable. you could try and replace the seal externally and while the seal is out youll get a better idea. put some tape on the crank and drill a 1/16" hole in the seal. use a screw in the hole to pull the seal out. then inspect the bearing better.

sounds like your on the right track though. right side crank seal. seals and bearing set should not be too expensive. mostly labor.

 

[rennat_2006]

I already pulled the seal using the method you said above! lol

Are the factory crank bearings the c3 type?

With the seal removed i can carefully use a screwdriver and turn the inner race on the crank side, So i know it has spun! :bang: Whether or not the crank is damaged is what im worried about, If we are lucky the bearing race would be damaged and no material would have been removed from the crank itself but i will only know when i get it torn apart.

Labor wont be a problems since i do all of my own work. The main problem is finding time to do it and my little brother affording the parts.

 

[Rotorranch]

The bearing race is harder than the crank. If the bearing spun, the crank is more likely to wear than the bearing race.

Rotor

 

[rennat_2006]

The bearing race is harder than the crank. If the bearing spun, the crank is more likely to wear than the bearing race.

Rotor

Thats what im planning on finding. My brother has his fingers crossed though :yell: