1950 Panhead Pinion Gear

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RooDog
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1950 Panhead Pinion Gear

#1

Post by RooDog » Thu Aug 09, 2018 12:56 am

While inside the cam/timing chest on my Project Panhead I noticed that the crank pinion gear (24010-39) which is a slip fit on the splined pinion shaft (24007-39) from 1939 to 1953 is quite loose. I discovered this when I worked the generator, bolted in place, shaft nut back and forth and saw lots of monkey motion in that gear train. One thing I need to address is the ignition idler bushings, but also that loose pinion on its splines is also quite sloppy. While looking in an older H-D parts manual is see part number "24010-51 Tight Fit 1951-53". As the same shaft services all OHVs from 1939-0953 is there any reason this gear would not work in this 1950 engine?
Does anybody have this gear?
How tight is it, does it work to eliminate the slop?
Any thoughts, fellas?
Thanks in advance..... RooDog



RUBONE
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Re: 1950 Panhead Pinion Gear

#2

Post by RUBONE » Thu Aug 09, 2018 3:07 am

The gear will work, however finding one may be an issue since they were never marked in any fashion. They also work with the new for '51 shaft with the screw in the end for the gear puller/installer to thread in. The puller sets he proper end spacing on the gear.
Do you have excessive noise in your cam chest? The amount of slop has minimal effect on the overall performance but can cause a click in the timing gears.

RooDog
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Re: 1950 Panhead Pinion Gear

#3

Post by RooDog » Thu Aug 09, 2018 3:44 pm

Rubone....Yes, I have noise in the bottom end. And it's is not consistent and rhythmic like lifter, valve lash, tappet noises would be, more like rattling gravel inside a tin can. I installed New jugs with matching pistons, new valves and guides. New lifter rollers. I did not disassemble the crank, but the rods felt good with no excessive slop and rotated smoothly. I did split the cases and visually check the main rollers too. It runs smoothly and with about as much power as one might expect from 74 inches, I'm used to my 100" Evo, and a hot rod Shovel. As I said it runs just fine, it just is embarrassingly trashy sounding. Yesterday I discovered the backlash between the pinion & gear. Also the bushings on the idler gears need to be serviced, those are available. I was not aware of an upgraded pinion shaft, mine has a slotted screw in the end, left hand thread I believe..... The real pisser about all this is that this engine has been in my family since 1967, and it is the noisiest one of all the engines I have ever worked on, and I have thrown together more than a few from junk parts that sounded just fine..... WTF?
Since there is no reasonable way to tighten that gear on the shaft I'll just have to live with it knowing that it is probably not self destructive......RooDog,

RooDog
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Re: 1950 Panhead Pinion Gear

#4

Post by RooDog » Mon Aug 13, 2018 10:26 pm

Rubone....
Hey, buddy....
Did I get lucky or what? One of the other Mean Old Bastards in town turned me onto a splined pinion gear, Clue: There were no polished rub marks on either end of that gear like mine had from flopping around on the shaft. When I went to fit this "new" gear it was tight, like hammer it on tight. I don't know it that is how the Tight Fit (24010-51) gear is supposed to be, but that is how this one is. So now with the gear, two new idler shafts and three new bushings I have eliminated 95% of the slop in the timing cover..... WooHoo... I hope this is what I'm needing to quiet down this old Panny.....Next up: Fix a leaky Bendix carb....Later.... RooDog

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Re: 1950 Panhead Pinion Gear

#5

Post by RUBONE » Mon Aug 13, 2018 10:34 pm

Lucky find, good for you. Be sure that the end measurement is set right, end of gear proud of the gasket surface by 5/16".

Andygears
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Re: 1950 Panhead Pinion Gear

#6

Post by Andygears » Mon Aug 13, 2018 11:52 pm

Heating on a 100 watt droplight will reduce hammering, works on evo inner primary race too!

My two cents
Andygears

RooDog
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Re: 1950 Panhead Pinion Gear

#7

Post by RooDog » Wed Aug 15, 2018 11:59 pm

Thanks for the input.Fellas....
Got the Panny back together today and fired 'er up.... WOW ! ! The ratly assed tin can full of rocks sounds are gone ! ! !. Just the sweet mechanical sounds of an old Panhead. Interestingly, I installed the solid pushrods two flats loose, on an Andrews #1 Cam. I've not ridden this scooter since I got it running this time, but I did let it idle up to temp, while I looked for oil and fuel leaks, the Bendix carb is another story, and it all sounds real good to my old years.....
So a recap: 1950 Panhead with new idler gear bushings and shafts, plus a used "Tight Fit" splined crank pinion gear taking all the slop and lost motion from the cam/timing gear train..... RooDog

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