primary case felt seal - virgin territory, over thinking, and brain farts...

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joe czech

joe czech

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(over thinking joe here - this is all somewhat new territory to me) -- looks like i'll be getting into my inner primary chain case to replace the felt seal. much to my surprise, it wasn't my case O-ring seal causing the leak, but the felt seal behind the clutch pack assembly. fairly sure I understand how everything goes together, but have a few questions. as part of my "over-thinking" research, I ran across this video - . it's a mod that adds in an additional "oil slinger" that was part of a Mk2a upgrade.

question 1) does anyone have the part number of the "oil slinger?"

2) has anyone done this mod - if so, worth the effort or is it overkill?

3) seems Michael Raber has retired, and he sold the business to CBS - if so, have they picked up the retrofit services? the mod doesn't seem to be too complicated, and fairly confident I could complete the task between my home shop, and my friends machine shop. again, worth the effort or overkill? I've seen some photos where folks have drilled out the spot welds, replaced the seal, and used small pop-rivets to reassemble the unit. the raber modification uses spot welds to re-assembly the modified oil slinger. it seems it could be a PITA to install a new seal in and between the existing inner/outer plates as is.

regarding the felt seal - better to pack the thing in a universal (synthetic) automotive grease, or soak in oil (thinking 140 weight - ???). I've got this brain fart where I could pack the felt seal with a very heavy coat of grease, and put it in a small vacuum chamber - pull a vacuum on the grease coated seal. quickly releasing the vacuum should force the grease deep inside the seal, essentially packing the felt with grease. again, a brain fart - looks good on paper, but don't know if it's even possible. figure it's worth a try.

sorry to be long winded. so, any comments based on past experience. gone thru the search mode, but still have questions. TIA....
.
 
Not sure the felt really does much sealing the oil in, rather it helps prevent grime from entering? I'm not detecting oil fling out of the primary since solving the blown crank seal and then a loose inner primary fixing bolt issue. I run ATF type F in the primary so it's lighter then engine oil, should fling/escape the felt easier but is doesn't seem to....and it's clearly different appearance than engine oil so I can ID source if it does leak.
 
joe czech said:
(over thinking joe here - this is all somewhat new territory to me) -- looks like i'll be getting into my inner primary chain case to replace the felt seal. much to my surprise, it wasn't my case O-ring seal causing the leak, but the felt seal behind the clutch pack assembly. fairly sure I understand how everything goes together, but have a few questions. as part of my "over-thinking" research, I ran across this video - . it's a mod that adds in an additional "oil slinger" that was part of a Mk2a upgrade.

question 1) does anyone have the part number of the "oil slinger?"

2) has anyone done this mod - if so, worth the effort or is it overkill?

3) seems Michael Raber has retired, and he sold the business to CBS - if so, have they picked up the retrofit services? the mod doesn't seem to be too complicated, and fairly confident I could complete the task between my home shop, and my friends machine shop. again, worth the effort or overkill? I've seen some photos where folks have drilled out the spot welds, replaced the seal, and used small pop-rivets to reassemble the unit. the raber modification uses spot welds to re-assembly the modified oil slinger. it seems it could be a PITA to install a new seal in and between the existing inner/outer plates as is.

regarding the felt seal - better to pack the thing in a universal (synthetic) automotive grease, or soak in oil (thinking 140 weight - ???). I've got this brain fart where I could pack the felt seal with a very heavy coat of grease, and put it in a small vacuum chamber - pull a vacuum on the grease coated seal. quickly releasing the vacuum should force the grease deep inside the seal, essentially packing the felt with grease. again, a brain fart - looks good on paper, but don't know if it's even possible. figure it's worth a try.

sorry to be long winded. so, any comments based on past experience. gone thru the search mode, but still have questions. TIA....
.
Click to expand...

Joe...
Quarantine has been hard on everyone...:p
A vacuum chamber....
Save it for the titanium welding project.
 
concours said:
Joe...
Quarantine has been hard on everyone...:p
A vacuum chamber....
Save it for the titanium welding project.
Click to expand...
Better yet, give the concept to AN and they can market it as a specialist tool for doing the felt. Make $$$, for sure!
 
Maybe the primary has been over filled for oil to get out of that felt seal, 7 fl oz of oil max in the primary, I usually run between 5 to 7 fl oz of ATF type F oil, the oil splashes on the chain to keep it lube.

Ashley
 
Think you meant Bob Raber retired. His son Michael is too young.
I added the “slinger” on my ‘72. Doesn’t really do much better. I’m surprised the belt drive guys haven’t started in for a leak free primary.
 
I did this modification on mine and it did help some but I still have an oil weep. I need to pull everything apart again and see what is up, as it might be coming from some other source.
 
This was my mod for an Atlas/Dommie sliding disc. The principles for the sliding disc can be applied to a Commando disc.

https://www.accessnorton.com/Norton...ominator-primary-oil-tight.26860/#post-403402

I wrote to pack the felt seal with heavy grease, but was informed the grease can work its way onto the clutch plates (read the entire thread). Perhaps Red Rubber grease would be better.

I do not see how the mod in the video "slings" oil .... the disc does not rotate. At best, it diverts oil around the transmission shaft on the inside surface of the inner disc (that closest to the clutch. My mod diverts oil around the transmission shaft between the discs.

An improvement to my mod would be to divert oil around the transmission shaft on the disc surface closest to the clutch by either:
1) forming a semi circular drip lip around the shaft hole in the disc using JB Weld, or
2) bonding a leather disc, having a hole for the transmission shaft, to the disc to function as a lip seal.

Even without this inner disc diverter, I was able to reduce my primary leak to a few drops after a run.

I would not spot weld the discs after any such mods, but rather use small screws and nuts as I explain in the link above. That way, changes can easily be made, or the felt seal renewed.

Slick
 
Last edited:
gawd, I need a hobby.... :D
ashman said:
Maybe the primary has been over filled for oil to get out of that felt seal, 7 fl oz of oil max in the primary, I usually run between 5 to 7 fl oz of ATF type F oil, the oil splashes on the chain to keep it lube.

Ashley
Click to expand...
don't think I've overfilled the primary - added until it started to come out the bottle plug, let it stabilize, and installed the plug. short 5 minute ride, and the bottom case is fairly wet - wet to the point of forming a massive drip. sure seems it coming from the aft part of the case around the felt seal. driving me nuts - about ready to tear that whole friggin case apart!
 
illf8ed said:
Think you meant Bob Raber retired. His son Michael is too young.
I added the “slinger” on my ‘72. Doesn’t really do much better. I’m surprised the belt drive guys haven’t started in for a leak free primary.
Click to expand...
didn't know there was a Bob and Michael - just assumed from the video. believe me, seriously thought about the belt drive, but if I do it, it will be in conjunction with an e-start. adding that in, and now it gets into "cost prohibitive"
 
Put it on side stand, drain into measuring cup. Lean it over and drain till empty. Put 7 oz back.

May work, if not, other leak can be fixed. Or ignored.

Did you soak the seal in oil before installation?
 
I feel your PAIN Joe! These Nortons can have so many ... "little issues." Constant maintenance/fix it battles ... has made me sell each one I had, then have sellers remorse! Look for and buy another, or assemble from parts; a really big PITA. On my eighth one now in 39 years. Guess we are all just "junkies." No other bike has such a devoted following and parts availability.
 
....all because some people think the internal aesthetics will scare the children

primary case felt seal - virgin territory, over thinking, and brain farts...


embrace, the PRACTICAL SOLUTION.
 
giving the O-ring thing one last shot before tearing into the primary case. had some 5.5mm silicone O-ring stock, so fab'd a new one, and gave it a coat of red rubber brake caliper grease. read on a couple threads that the red rubber grease may be a better alternative over plain automotive grease. gawd, I hate oil leaks - :mad: - almost as much as paying taxes. this one's driving me friggin nuts!
 
I've replaced the felt seal once in 45 years and recall it being a real PITA. I think I stuffed it in using a small screwdriver. Still leaked afterward. C'est la vie.

illf8ed said:
I’m surprised the belt drive guys haven’t started in for a leak free primary.
Click to expand...

Funny, that. With a belt drive my paranoia of primary leaks has actually increased. The inner chaincase on the cNw e-start has cooling slots cut into the bottom, and any oil emerging from either the main seal or clutch pushrod will find its way to the ground.
 
joe czech said:
didn't know there was a Bob and Michael - just assumed from the video. believe me, seriously thought about the belt drive, but if I do it, it will be in conjunction with an e-start. adding that in, and now it gets into "cost prohibitive"
Click to expand...
Me too on cost. How much is drip cure worth? The triple row primary chain works so well, but others complain about the weight. I can go on a diet less costly than a belt kit.
Raber’s in San Jose is history. Bob really deserved a retirement. He supported local Brit bike clubs for many years and a general great place to congregate.
 
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