The Last Leak

texasSlick · May 2, 2021

The last leak on my Atlas succumbed to a lip seal on the transmission shaft where it passes thru the sliding discs.

My method:
Separate the sliding disks, and invert the inner disk. This puts the felt washer pocket towards the clutch basket.
Inside that pocket, I JB Welded a shaft grease seal (McMaster Carr #5154T61, or 1 1/8" ID x 1 3/8" OD). The seal lip just barely closes over the transmission shaft, when the inner primary cover is fitted (Atlas anyway).

Adjusting the primary chain requires some care: since the seal is pliable, when the gearbox is adjusted, the transmission shaft will push the seal and sliding disks off center. The primary chain should be adjusted over-tight, about 1/4" up/down play, then the gearbox moved 5 flats on the adjuster nut towards the front (loosening the chain). The 5 flat turn of the adjuster bolt should re-center the disk and seal. Vibration will help perfectly center the disk and seal.

The felt washer is compressed by flipping the inner disk over. This also helps prevent oil migration. Commandos should respond to this treatment as well, although the shaft circlip may be a problem.

With no leaks, I hardly know what to do with myself...... should I:
A) quit while ahead
B) put the bike on a pedestal, with a suitable plaque and never ride it again
C) buy another Norton and start all over again

Slick

Nater_Potater · May 2, 2021

texasSlick said:
With no leaks, I hardly know what to do with myself...... should I:
A) quit while ahead
B) put the bike on a pedestal, with a suitable plaque and never ride it again
C) buy another Norton and start all over again

Slick

Well, "C" of course! The mere fact that we wide Nortons proves we're a bunch of masochistic nit-wits. Just ask the missus...

johnm · May 2, 2021

I was very pleased with myself and got my 1956 500 crankcase with SS head Dommie race bike totally oil tight. Even under race conditions as demonstrated by completely clean oil pan under the faring. I ran several breather pipes through a BMW airhead breather reed valve.

But store it in the shed over winter and it would wet sump. And as soon as the oil got half way up the cases it would leak. Porous cases just at the front. But it never leaked while running with the breather fitted.

jbruney · May 2, 2021

Be patient and allow a little time for your bike to get back on track and it'll again leak for you in an endearing manner..... At least mine does.

cjandme · May 2, 2021

Well Nater_Potater beat me to it since I was going to vote for option "C" also, but now that I think about it ….how 'bout option D...ride it like you stole it! something is bound to happen

robs ss · May 2, 2021

E) - wait a little while and a new problem will present itself @grandpaul !

maylar · May 3, 2021

They don't leak, until they do. Ride it and you will find out.

grandpaul · May 3, 2021

robs ss said:
E) - wait a little while and a new problem will present itself @grandpaul !

Only if the bike is actually ridden.

Otherwise, you might have to wait QUITE a while for the bike to present typical "sat up" problems...

YING · May 3, 2021

texasSlick said:
The last leak on my Atlas succumbed to a lip seal on the transmission shaft where it passes thru the sliding discs.

My method:
Separate the sliding disks, and invert the inner disk. This puts the felt washer pocket towards the clutch basket.
Inside that pocket, I JB Welded a shaft grease seal (McMaster Carr #5154T61, or 1 1/8" ID x 1 3/8" OD). The seal lip just barely closes over the transmission shaft, when the inner primary cover is fitted (Atlas anyway).

Adjusting the primary chain requires some care: since the seal is pliable, when the gearbox is adjusted, the transmission shaft will push the seal and sliding disks off center. The primary chain should be adjusted over-tight, about 1/4" up/down play, then the gearbox moved 5 flats on the adjuster nut towards the front (loosening the chain). The 5 flat turn of the adjuster bolt should re-center the disk and seal. Vibration will help perfectly center the disk and seal.

The felt washer is compressed by flipping the inner disk over. This also helps prevent oil migration. Commandos should respond to this treatment as well, although the shaft circlip may be a problem.

With no leaks, I hardly know what to do with myself...... should I:
A) quit while ahead
B) put the bike on a pedestal, with a suitable plaque and never ride it again
C) buy another Norton and start all over again

Slick

Buy another one!

texasSlick · May 3, 2021

Ooops! This thread was meant to suggest a lip seal might benefit Commandos. The Options listed was intended to be "tongue in cheek" humor. Anyway, Option C is in my head right now. See the For Sale Section below .... the 73 Commando in Dallas is piquing my interest .... no need to bring a trailer, just ride it home, assuming the missus will drive me to Big D.

jseng1 · May 3, 2021

johnm said:
I was very pleased with myself and got my 1956 500 crankcase with SS head Dommie race bike totally oil tight. Even under race conditions as demonstrated by completely clean oil pan under the faring. I ran several breather pipes through a BMW airhead breather reed valve.

But store it in the shed over winter and it would wet sump. And as soon as the oil got half way up the cases it would leak. Porous cases just at the front. But it never leaked while running with the breather fitted.

The BMW airhead reed valve is my favorite. Along with silicone gaskets, yamabond, pliobond and oversize O rings - my Atlas hasn't leaked in years.

Schwany · May 3, 2021

I like the optimism.

Resistance is futile with Norton leaks on the planet I am from. I have been assimilated.

Like Jim I know I could stop them with enough goo. I just don't like taking things apart after using the goo.

jbruney · May 3, 2021

I like'em... keeps rusting at a minimum.

maylar · May 3, 2021

jbruney said:
I like'em... keeps rusting at a minimum.

You do have to be aware, however. My buddy let his primary leak until empty and the chain did not fare well.

jseng1 · May 3, 2021

You don't need any goo with silicone gaskets. Goo only on the case split, the cylinder base and head gasket.

Schwany said:
I like the optimism.

Resistance is futile with Norton leaks on the planet I am from. I have been assimilated.

Like Jim I know I could stop them with enough goo. I just don't like taking things apart after using the goo.

Schwany · May 3, 2021

jseng1 said:
You don't need any goo with silicone gaskets. Goo only on the case split, the cylinder base and head gasket.

The Matchless primary cover on the P11 is the only leak I have, but I have decided to just refill as required and put up with it after many attempts to make it leak proof. Do you have a silicone gasket for that Matchless primary? Kidding I know you don't. Permatex Right Stuff would seal it up, but I'd need a jack hammer to take it apart after using that stuff.

MikeG · May 3, 2021

My take on the same solution. An aluminum holder with a lip seal sandwiched between 2 plates and a copious smear of RTV just for the heck of it. I have adjusted the chain several times over the last few years it's been there and never seen a hint of a crack in the RTV.

Commando750 · May 3, 2021

texasSlick said:
Ooops! This thread was meant to suggest a lip seal might benefit Commandos. The Options listed was intended to be "tongue in cheek" humor. Anyway, Option C is in my head right now. See the For Sale Section below .... the 73 Commando in Dallas is piquing my interest .... no need to bring a trailer, just ride it home, assuming the missus will drive me to Big D.

Slick, no need to get the missus involved-I'm up for a road trip. I'll pick you up when you're ready. You're a braver man than me to drive in Dallas traffic!!

Mike40M · May 3, 2021

I would never say last leak, I'd say latest leak. The only leak free English bike I have (of 8) is the Manx.
Not true, one drop of oil from the rev counter gearbox after a full race season. But of course a lot of chain grease, especially from the primary chain.

Craig · May 3, 2021

Exactly way I feel , was drip free going on 6yrs …. just this spring noticed a very small wet spot on frame under shift lever , figured it was a drip I missed during clean up after gearbox oil change …. Nope ! It appears either the seal has failed or has moved from it’s sweet spot …. I did get the odd positive comment though ,previously on how dry my Commando was …. will wait for a rain day now before having a look ….. did someone mention it a never ending challenge ……

The Last Leak

texasSlick

Nater_Potater

johnm

jbruney

cjandme

robs ss

maylar

grandpaul

YING

Pittsboro,NC

texasSlick

jseng1

Schwany

jbruney

maylar

jseng1

Schwany

MikeG

Commando750

Mike40M

Craig

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