View Full Version : Harley Pinion Gear Fit

Bill Pedalino
10-06-2010, 09:16 AM
I am assembling the lower end for my 1953 FLE and have come across a problem that I remember reading about years ago. The pinion gear fits loosely on the pinion shaft splines. From what I remember, this was a problem for H-D in the early 1950's and I believe the Factory's position was that this loose fit caused tapping noise to eminate form the gearcase. Of course, I did not check this fit until AFTER I assembled and trued the flywheels (You'ld think I'd learn after all these years...).

From what I remember, the factory first solved this problem by copper-flashing the pinion shaft splines on the shafts that were already manufactured, thus tightening up the gear fit on the splines. I remember remnants of this plating on of these plated shafts when rebuilding early panhead motors years ago. Apparently later pinion shaft runs, and/or pinion gear runs had the tolerances tightenen up to a slight interferance fit between the gear and the shaft splines.

I have an original H-D pinion gear, a new S&S pinion gear, a new Jim's pinion shaft, an Eastern pinion shaft and an original H-D pinion shaft (that is not useable). All gears fit equally loose on all shafts and have slight side shake between the gear and splines, regardless of the combinations used.

The flywheels are assembled and I really would prefer NOT to take them apart again. So, aside from copper plating the pinion shaft splines, does anyone have any suggestions? Also,, before going off on an unnecessary tangent, was the factory correct in its assertion that gearcase noise resulted from tne slip-fit?

Bill Pedalino

10-06-2010, 09:44 AM
Bill, I have an assortment of gears, the fit of these gears on any given shaft will vary substantially. I would try to put your hands on a few more gears to look for a good fit before a teardown. If you can't do anything locally, send me a PM and I'll see if I can help.

10-06-2010, 09:52 AM
Bill email Kyle the spline diameters [ both male and female ] of the pinion shaft and the widths of its splines as well. He will have an easier time matching one up for you. Paps

Bill Pedalino
10-06-2010, 07:31 PM
Thanks gentlemen, I'll measure the shaft tomorrow.