Crankshaft Inner and Outer Bearing Races

[Mito]

Hey Everyone, I started assembling my XB12r crankshaft and cases today. I have replaced both the pinion side inner and outer bearing races and tried using the HD bearing chart to select the correct needle roller grade to achieve the right running clearance. Problem is, the inner race OD should measure around 1.250" but is actually 1.258" and the outer race ID should measure around 1.564" is actually 1.563". These sizes are way out of spec to get any of the needle rollers to fit. Question: are the inner and outer races finished to size out of the packet or is there further sizing to be done to get them to spec. Eight thou bigger on the inner race OD seems a lot or did someone on Quality Control just have a bad day. Cheers, Stu

 

[Cooter]

Hey Stu, you are right, the clearance is determined by the roller size. The inner and outer races should be a standard size and not machined to fit. How was the install on that inner race? Too easy?

 

[Mito]

Thanks for that. The inner race pressed on fine....firm but not excessive. I didn't measure the race before installation so unable to determine if it expanded during fitting. Eight thou is a lot to expand though and would definitely have felt that. I will start again and get some another set of races as they are not expensive. I have the set of four needle rollers to select the correct clearance.

 

[Cooter]

Ya you'd never get that on like that! Pretty odd to be that far out though, and I can't imagine a need for a 'oversized' inner race for needle bearings? Is that a thing?

 

[Mito]

Hey Cooter, I ordered in another inner and outer and they were the same so fitted the inner on the crank and ground it to size insitu. The outer race measured 1.564" fitted so had to take inner down to 1.248" and fitted a "green" roller to get half a thou running clearance. Bit of a mission but got there.