Topic: Do I have a non-stock rear hub/bearing/axle on my cb350 Twin?

[Cowboy]

I replaced the wheel bearings recently on my CB350 twin. When I put things back together, I slid the axle through the oil seal/bearing retainer, and through both bearings, and everything felt nice and snug. When I rode the bike a few miles, something was obviously not right. I got home and found that the new bearing on the left side of the hub was apparently loose on the axle shaft, and the slop was allowing the axle spacer to grind into the dust shield/bearing retainer. My dust shield is ruined, and  my new bearing will be ruined when I take it out.

I've been having a discussion with the supplier I bought my bearings from, and they insist that they sent me the correct bearing. They tell me that my axle shaft should be 17mm where it passes through the right side bearing, but 20 mm where it fits inside the left side bearing.  This is definitely not the case with mine. My axle shaft is 17 mm along its entire lentgh. Both my old bearings fit snugly on that 17 mm shaft. Despite the fact that they are both 6304 bearings, the old one and the new one have different inside diamters, and the new one is sloppy on the shaft, with about 2mm free play. 

My question is, on your CB350 twins, is your rear axle shaft the same size along the entire length, or does it have a larger diameter on the left side?

Are there any sleeves on your axle shaft where it passes through your left side rear wheel bearing. Does anyone else have an axle shat that is the same diamter along its entire length?

[Cowboy]

Hmmm . . . rebuilt innumerable old cars, and a little motorcycle bearing had me stumped. You'd think it was exotic technology or something.

Turns out that my old wheel bearing had an inside diameter of 17 mm because it had a spacer inside it. Said spacer doesn't come out very easily with the bearing mounted in a vise, even when you're pounding on it with a big drift and a girt big hammer.  Comes out real easy when you take the bearing out of the vise, and quit squeezing the backside of the spacer in the vise.   Shame that girt big hammer and drift beat the spacer into jagged bits.

Seems I'll be buying a new spacer AND a new bearing retainer.  The good news is that the new bearing I have is the correct size after all. 

One way to keep all those folks from laughing AT you is to laugh along with them. If I keep laughing, maybe I won't cry.

[Sam Green Racing]

We all learn from our mistakes. 

Sam.

[Green550F]

Thanks for the post! If it makes you feel any better, you've prevented me from making the same mistake later when I replace mine!

[cb650]

I think nobody has ever done that before .




                        Terry