Pinion races

[Steve Little]

Hi. Hope everyone is well.
I have a couple of NOS pinion races which were an impulse purchase from ebay some years ago. Might have been from easyruss who I liked buying from.
All external dimensions are same as 1940-54 BT over head valve pinion race, except the ID which is 1 3/8” instead of 1 ˝”.
I had a browes through the parts and service manuals, and the Jims part manual, but couldn’t see any reference to inside dimensions.
I have never worked on a BT side valve, so I am wondering if these might be the pinion races for that style engine?
Hoping some of you part savants might be able to clear this up.
Regards Steve

[Rubone]

Sounds like they are for '55-'57 models. Any snap ring grooves in them? There are a couple different types, a '54 only and '55-'57, but all share the same ID. They used a 3/16 diameter roller set, the '55 up is the same set as a Sportster or K-Model. They are shown in Shop Dopes and some of the Panhead service manuals. The '55-'57 pinion shaft uses the same gears as a '58 up, keyed oil pump drive and taper fit pinion with a nut.

BT sidevalve uses the same stuff as a Knuckle or early Pan.

[Steve Little]

Hi Robbie. Thanks for the information.
No circlip grooves. It has the later style grub screw recesses in both sides. Maybe unfinished stock??

P4150001.jpg

[Steve Little]

Strike my last comment "unfinshed stock?" These are hardened and they wouldn't do that with an 1/8" still needed to come out.

[Steve Little]

Hi Robbie. Sorry. I'm a bit slow today. Are you tagging these as 55-57? OEM 24599-55. Regards Steve

[Rubone]

Hi Robbie. Sorry. I'm a bit slow today. Are you tagging these as 55-57? OEM 24599-55. Regards Steve

Yes, I am.

[exeric]

While on the subject of the pinion area; should the oil pump drive gear be a slip fit, or light press fit on the splined pinion shaft for a '48FL? I've already made a puller, and pusher for the OPDG, and pinion gear, but wondering if the OPDG needs to float a bit on the shaft. I have looked through my books, and missed that bit of info. Thanks in advance for enlightened advice.

[Rubone]

The early splined shafts were a slip fit, which proved to be a bit noisier. From '51 up the splines were enlarged slightly to create a press fit. Those shafts had a reverse threaded end with an appropriate screw to plug them enabling a puller to be used for installation and extraction. They were a retro-fit part that could be used for any earlier Big Twin.

[exeric]

You're a gem, Robbie. My oil pump drive gear goes on with some effort so I guess the spring in that assembly is somewhat superfluous. I'll use the puller/pusher tools because I'm not going to disturb the pinion location after busting a nut truing the flywheels. Thanks again, Robbie, most appreciated.

[Steve Little]

Yes, I am.

Thanks Robbie.