1952 panhead pinion shaft

[lrcormier]

I've recently resurrected my 1952 Pan head project and have a question concerning the correct pinion shaft. The bottom end was done by the previous owner and assembled with 80 inch flywheels from a 80 inch flathead (old school stroker), the problem is I have no way of finding out what he used for the pinion shaft and the one currently installed does not allow the oil pump drive gear and pinion gear to easily slide on like I believe it's suppose to, it's sort of a press fit. After some digging it seems there are two HD part numbers for the pinion shaft, 24006-39 and 24007-39, can someone tell me what the difference is between these two shafts and or which one I should use?

[wideglide38]

lrcormier, My '41-'54 parts manual indicates the 24006-37 (I did not find p/n 24006-39) is for '37-'48 74" & 80" side valve models and the 24007-39 is for '39-'53 OHV models. William

[Rubone]

Ideally the pinion gears are a light press fit, the oil pump drive a slip to allow it to self center. It is covered in the factory manuals..

[lrcormier]

Thanks for the replies. Robbie, it makes sense that the oil pump drive gear should slip and I believe that's what the description said I used when I fitted the gear by honing the shaft in order to get it to slip. I acquired the gear separately from someone who I observed using a puller to remove it from a shaft on a motor he had recently destroyed (it was a knucklehead), the gear fit on that shaft was definitely a press fit. Based on some research it appears HD did experiment some between press fit and slip fit and I think that may be what the difference is between pinion shaft 24006-39 and 24007-39 is, with 24007-39 being the press fit shaft and likely the one I don't want because the press fit for the oil pump drive gear did cause some problems. The issue is that both shafts can sill be purchased. I might just be overly concerned because I was thinking I may have ruined the shaft currently on the motor by honing on it in order to get the oil pump drive gear to slip, but perhaps what I did was the right thing? Am right in thinking that maybe this is really not as big a deal as I'm making it out to be. Finally my last question has to do with the pinion gear, I had picked one up used put it looks pretty worn, I would like to purchase a new one but it appears there maybe as many as three different ones (standard, orange, black) how do I know which one to get?

[lrcormier]

Update to my original question and some replies I received below: HD changed the pinion shaft several times over just a few years and someone must know the difference. You can buy either 24006-39 and 24007-39 on the internet from various sources and apparently either one could work, but there has to be some difference and I think it has to do with either a slip fit or a press fit?

-----Original Message-----
From: admin [mailto:justpanhead.com@charter.net]
Sent: Monday, January 16, 2017 9:59 PM
To: louis.cormier@cox.net
Subject: Re: PINION SHAFT FOR 1952 PAN

Hello,louis

24006-39 is manufactured in USA by Eastern manufacturing.

24007-39 is manufactured in USA by JIMS and includes part # 24020-51 gear shaft plug (the screw that goes in the end of the pinion shaft). 1.000" is standard O.D. for shaft

Both are good shafts. If you need the screw go with JIMS

Hope that helps

Thanks
Justpanhead.com

From: Jeff May [mailto:easternmcparts@yahoo.com]
Sent: Tuesday, January 17, 2017 12:25 PM
To: Louis Cormier <louis.cormier@cox.net>
Subject: Re: PINION SHAFT FOR 1952 PAN

Hi Louis
The only one we sell and everyone buys is 24006-39 it replaces 24007-39
I cant tell you the different or what/why harley superseded that number
You will be good buying 24006-39




Thank You
Jeff May
Eastern Motorcycle Parts
5120 Hilda Rd
Blackville, SC 29817
Phone: 803-284-3304
Fax: 803-284-3274
www.easternmotorcycleparts.com

[billpedalino]

Thanks for the replies. Robbie, it makes sense that the oil pump drive gear should slip and I believe that's what the description said I used when I fitted the gear by honing the shaft in order to get it to slip. I acquired the gear separately from someone who I observed using a puller to remove it from a shaft on a motor he had recently destroyed (it was a knucklehead), the gear fit on that shaft was definitely a press fit. Based on some research it appears HD did experiment some between press fit and slip fit and I think that may be what the difference is between pinion shaft 24006-39 and 24007-39 is, with 24007-39 being the press fit shaft and likely the one I don't want because the press fit for the oil pump drive gear did cause some problems. The issue is that both shafts can sill be purchased. I might just be overly concerned because I was thinking I may have ruined the shaft currently on the motor by honing on it in order to get the oil pump drive gear to slip, but perhaps what I did was the right thing? Am right in thinking that maybe this is really not as big a deal as I'm making it out to be. Finally my last question has to do with the pinion gear, I had picked one up used put it looks pretty worn, I would like to purchase a new one but it appears there maybe as many as three different ones (standard, orange, black) how do I know which one to get?

From what I remember, the 24007-39 part number was a revised shaft that was intended to reduce the noise generated buy the slip-fit pinion gear. The earliest updated shafts were widened by applying a copper flashing to the spline area. My guess is that this was probably done as an interim 'fix' for the new shafts that the factory already had on the shelf and I had seen a couple of these plated shafts years ago in motors that I disassembled for rebuild. I would assume that the 'newer' 24007-39 pinion shafts were ground to a larger spline outer diameter.