Help! Center main bearing won't fit

[nickolai]

So I started putting my ea81 together, and the center main bearing (the one with the flanges on the sides) won't fit on the crankshaft. The flanges are just a hair too wide. The other two bearings fit just fine and are definitely the right size for the the crankshaft. Any ideas?

[naru]

A shot in the dark.....

 

Did you have the crank machined for undersize bearings?

I think some undersize bearing sets expect you machine the crankshaft thrust surfaces as well as the journals.

 

Pretty sure the set I used did not require this.

[nickolai]

Thanks for the quick reply. I did have it machined. To .25mm under. Would it be better to have the crank re-machined or try to find the right bearing? I don't suppose there's anything I can do to the one I've got to make it fit.

[naru]

Better to have the crank remachined.

That way crank thrust clearance will be right on the money.

 

Maybe you could use a different bearing set.

 

I see the Clevite .25mm undersize set has a thrust bearing .15mm longer than stock.

Take the bearing with you to the machine shop.

Edited March 10, 2011 by naru
clevite

[ShawnW]

A lot of machine shops don't cut the thrust surface unless you provide the bearings you are going to install or the manufacturers specs. As Naru has stated, take the bearings and the crank to the shop for sizing.

[nickolai]

Thanks for the info. I wish I had known this beforehand...