Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Pinion Gear not a slip fit

Pinion Gear not a slip fit

Post Thu Feb 16, 2012 10:32 am

Posts: 7
The pinion gear for my WLA is definitely not a "slip fit" right now...the spiral gear slips on nicely, but the pinion gear, after polishing up both the pinion gear and the shaft, is a press fit. The binding area appears to be where the larger spline on the shaft contacts the pinion gear I.D.

Any thoughts on what could have caused this, and how to get around it? Not sure if I should look to get a new pinion gear, try to grind the existing one down just a tad, or what.



Post Thu Feb 16, 2012 11:31 am

Posts: 391
You are lucky. The best fit for a pinion is tight, not slip. The looser the slip the more noise it makes and adds to variations in timing due to lash. Keep it tight!

Post Thu Feb 16, 2012 1:24 pm

Posts: 7

Thanks for the input. I guess I was concerned that it is supposed to be spring loaded to press back against a bushing in the side cover or something similar. As tight as it is now, I'd need a heck of a spring to move it on the shaft... I'm learning as I go on this one...


Post Thu Feb 16, 2012 10:36 pm

Posts: 391
The spring keeps the sealing ring against the main bearing race, it does not hold the gear in place. The pressure is very light on it, hence the light spring. The gear is to sit 5/16 off the case face. The less it moves the better.

Post Fri Feb 17, 2012 2:18 pm

Posts: 303
Location: wooster oh usa
we always honed parts with a pocket stone to be tight slip fit for restoring bikes for street was another story... those we set up a little on the loose side for expansion in extreme conditions.

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