Crankshaft bearings

Jaycee604

Jaycee604

Member
So i just installed new bearings and i forgot to take off one of the seals on the inside where they connect to the crankshaft. I am aware they should have one side open to get lubed by oil, i removed one side of only one of the bearings and forgot to take off the other side. Engine is complete and on the bike dont want to take it apart all over again. Can i get away with leaving it on? 6202 rs from PGN bearings
 
The bearing with the seals in place is designed for no more than maybe 3250 rpm, I don't think it would last at 7000 rpm, there's not enough grease and what's there would liquefy and move to one location in the housing at high speed. Fresh fuel helps cool the bearing.
I would take it back apart and remove the seal, I leave both outside seals and that works fine.
 
Damn, its what i feared. Just to make it clear its just one of the bearings and the 6202 rs is a rubber seal, dont you think the rubber seal inside would fail? Resulting in it failing and then letting oil in anyway? The seal would never fall off because there isnt much space between the bearing and crank
 
Well i took the advice and took her apart, popped that seal off. While we are here i have a concern. The bearings are great, engine turns over very smooth and free, but when i go tighten the bolts down the crank gets harder to turn over. All bearings are seated, no shims are on this crank. Really confused guys
 
Did you notice one case gasket or did it have two? Some come with two. If it will turn by hand it should loosen up after running.
 
First, I would double check that the bearings are truly seated all the way in the cases & you didn't miss seeing a shim.

Sometimes if the crank has tiny burrs, the bearings can be difficult to slide all the way down...
With the cases assembled (& crank installed), try gently tapping the ends of the crank back & forth with a soft hammer & see if that does the trick.

Please report back how it went.
 
Update, once i put the cases together and tightened them i put the screw on the end of the crank and gave it a couple of wacks to center it and it freed right up. Spins like a charm now. It only had one case gasket and no shims, ive only seem on crank ever with shims
 
I’ve got a grubee that I’m about to take back apart because it needs shims, it has side to side movement that causes deceleration vibration. I have some copper washers I’m going to use as shims.
 
Greg58 said:
I’ve got a grubee that I’m about to take back apart because it needs shims, it has side to side movement that causes deceleration vibration. I have some copper washers I’m going to use as shims.
Click to expand...
I've got stainless shims in various thickness to put between the crank and bearings and or bearings and case to tighten things up... I'm going to put bushings to shim the grudgen pin also to try and correct the rod, crank and piston floating around and a crowded bearing on the big end...
 
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