Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Modern tranny sprocket seal

Modern tranny sprocket seal

Moderators: Curt!, Pa

Post Mon Jun 27, 2011 8:33 pm

Posts: 36
Is there a modern lip seal available to fit the gearbox output sprocket on my 42WLA?
Or are we stuck with the old leather ring?
Anyone happen to know a size or number so I can check if my local bearing shop has one before I pull the sprocket off?

Post Mon Jun 27, 2011 9:53 pm
Pa Site Admin

Posts: 5769
Location: Ohio USA

If your oem seal is leaking bad, it is most likely because the seal is dry rotted and cracked... or the mainshaft races outer drive sprocket seal surface is deeply grooved through many years of use. NOS oem seals are still very good if warmed up good before installing the sprocket onto the mainshaft. I now heat them up to roughly 175 degrees before installing them. The heat seems to make them plyable again.

Post Tue Jun 28, 2011 12:28 am

Posts: 36
Pa wrote:
If your oem seal is leaking bad, it is most likely because the seal is dry rotted and cracked... or the mainshaft races outer drive sprocket seal surface is deeply grooved through many years of use. NOS oem seals are still very good if warmed up good before installing the sprocket onto the mainshaft. I now heat them up to roughly 175 degrees before installing them. The heat seems to make them plyable again.


That is interesting. Do you heat them up in oil presumably?

Still would like to find a standard seal as parts take 3-4 weeks to get from the US to the remote part of Oz where I live, but we have a local bearing supplier with a good stock of lip seals.
I am sure my old seal has suffered some rot - it has been in there since I restored the bike 38 years ago.
Just pulled her out of my late father's shed recently and am trying to breathe a bit of life back into the old girl, on a really limited budget both time and money wise.

Not sure how to post pics but I'll give it a try:
Then
Image

Now:
Image

Post Tue Jun 28, 2011 6:19 am

Posts: 640
Location: Wisconsin, USA
I think it's great you've hung on to the motorcycle. You and the machine don't seem to have changed much. Enjoy the ridin'. I'll look to see if the aftermarket seals I have are numbered.

Post Tue Jun 28, 2011 8:01 am

Posts: 304
Location: Jonesville, Louisiana, USA
Nice bike, Hopper. I recently had to change my tranny sprocket seal for the same reason, dry rotted.

Post Tue Jun 28, 2011 8:49 am
Pa Site Admin

Posts: 5769
Location: Ohio USA

Very nice bike ! You have just the Bro in your neck of the woods [Australia]. Email Tony at redfernmotorparts@bigpond.com . I am certain Tony will have the nos seals. Ask for an nos sprocket instead of just the seal. The seal will already be installed in the nos sprocket. To answer your warming of the seal question....no....I do not warm them in oil. The nos seals, and or the nos sprockets, are coated in cosmoline, and.... to remove the vast majority of this preservative, the heat accomplishes that task and simultaniously enhances the softening process to boot.

Post Tue Jun 28, 2011 9:02 am

Posts: 304
Location: Jonesville, Louisiana, USA
Pa wrote:
Very nice bike ! You have just the Bro in your neck of the woods [Australia]. Email Tony at redfernmotorparts@bigpond.com . I am certain Tony will have the nos seals. Ask for an nos sprocket instead of just the seal. The seal will already be installed in the nos sprocket. To answer your warming of the seal question....no....I do not warm them in oil. The nos seals, and or the nos sprockets, are coated in cosmoline, and.... to remove the vast majority of this preservative, the heat accomplishes that task and simultaniously enhances the softening process to boot.


Cool.

Post Tue Jun 28, 2011 8:09 pm

Posts: 36
amklyde wrote:
I think it's great you've hung on to the motorcycle. You and the machine don't seem to have changed much. Enjoy the ridin'. I'll look to see if the aftermarket seals I have are numbered.


Thanks.
Mmmm, but like the bike, I am bit tireder in the second pic. :wink:

Post Wed Jun 29, 2011 7:29 am

Posts: 640
Location: Wisconsin, USA
I couldn't find any sprocket seals in my 45 stuff, just clutch gear seals, no numbers. The bearing supply outfits usually have seals listed by dimension in their catalogs so if you had a way to measure the od of the boss on the side cover and the id and depth of the counterbore in the sprocket, you should be able to purchase a seal.

Post Wed Jun 29, 2011 5:29 pm

Posts: 391
The stock sprockets have a seal retainer in them, a stamped steel shim of sorts. Why, who knows, perhaps a change in seal standardization or such. I would not worry about the OD, find a seal that fits the boss on the end cover and make your own "seal retainer" to fit the OD to the sprocket.
Robbie

Post Wed Jun 29, 2011 8:40 pm

Posts: 36
RUBONE wrote:
The stock sprockets have a seal retainer in them, a stamped steel shim of sorts. Why, who knows, perhaps a change in seal standardization or such. I would not worry about the OD, find a seal that fits the boss on the end cover and make your own "seal retainer" to fit the OD to the sprocket.
Robbie


That is probably what I will end up doing. I have access to a lathe.
Guess I have gotten spoilt over the years riding modern bikes and just can't tolerate oil patches on the garage floor. Even my Ironhead is not allowed to do that.
Though, the old Walla is something special.

Post Wed Jun 29, 2011 10:26 pm

Posts: 72
Location: South Australia
:shock: My goodness you washed the old girl, must be first time yeeeears, looks good, big red is near on all done.
" The more I learn the less I know"


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