primary seal

bchessell2 · Jul 22, 2022

What is everyone using for there primary seal.I got a soft foam type one from walridge but it leaks shortly after putting it in.I know in the past some on the forum have been buying in bulk and making ther own.At one time they were made from a harder material and seemed to last.I used to leave them in after primary oil changes and just apply silicone.

WEM · Jul 23, 2022

I’ve had good success with the sealing band supplied by Andover Norton. Might be the same one Walridge supplies. Don’t know. Following advice from a Forum member, I put a thin layer of grease in the sealing band groove. Not sure if this makes a difference but can’t argue with the results. FWIW, I placed my last order with A/N on a Friday and had delivery from Great Britain on the following Tuesday morning. Amazing. Canada Post takes 10 days to get a letter across the country.

Northton · Jul 23, 2022

WEM said:
I’ve had good success with the sealing band supplied by Andover Norton. Might be the same one Walridge supplies. Don’t know. Following advice from a Forum member, I put a thin layer of grease in the sealing band groove. Not sure if this makes a difference but can’t argue with the results. FWIW, I placed my last order with A/N on a Friday and had delivery from Great Britain on the following Tuesday morning. Amazing. Canada Post takes 10 days to get a letter across the country.

I have the same seal and I thought it was leaking but it was actually coming from the felt seal at the back of the primary and migrating to the bottom of same.

Tornado · Jul 23, 2022

I had the soft foam band for a while. Can't recall if it leaked, but do recall it ripping apart when I had the cover off next.
Replacement was the harder rubber. It also split at a removals in the past, though I did have sealant on it I believe. Latest is same hard rubber, black gasket maker type sealant (poly urethane?). No apparent leaks.

elefantrider · Jul 23, 2022

Old band coated both sides with Hylomar Advanced.

cliffa · Jul 23, 2022

bchessell2 said:
What is everyone using for there primary seal.I got a soft foam type one from walridge but it leaks shortly after putting it in.I know in the past some on the forum have been buying in bulk and making ther own.At one time they were made from a harder material and seemed to last.I used to leave them in after primary oil changes and just apply silicone.

I have an original hard band somewhere. It's yours for the postal cost if you want it.

Shelby-Right · Jul 23, 2022

I think they leak so easily because the oring groove is rough cast and the o-ring can't conform , so sealant fills in the gaps .Cheers.

bchessell2 · Jul 23, 2022

I am going to take the primary apart and check out everything including flatness and the felt seal.Thanks guys for the input.

Time Warp · Jul 23, 2022

Even the new inner primary covers look to be as cast as far as the sealing groove.
They could be CNC machined to suit a square section cord along with a positive stop ( I have a shim at that location to set the squish/compression) at the centre stud (Non Mk3)

Perhaps over tightening the centre nut can lead to distortion of the inner cover if excessive, that would come back to the bosses on the covers (stud)

bchessell2 · Jul 24, 2022

I am feeling my 75 years right now and I apologize for even posting this problem of leaking at the primary. Years ago in the 70s on my 68 commando I drilled and tapped for a 1/8 pipe tap the inner primary for a 90 degree brass fitting just ahead of the clutch basket above centre .I then put a 1/4" hose up to the battery box to vent any build up of pressure as small as it seems to the atmosphere.Worked great as leaking was always a problem.That is what I will do .

Craig · Jul 24, 2022

Or just use heavy/thick grease on your soft o-seal , should work fine , plus you won’t tear it on removal ….

Tornado · Jul 24, 2022

bchessell2 said:
I am feeling my 75 years right now and I apologize for even posting this problem of leaking at the primary. Years ago in the 70s on my 68 commando I drilled and tapped for a 1/8 pipe tap the inner primary for a 90 degree brass fitting just ahead of the clutch basket above centre .I then put a 1/4" hose up to the battery box to vent any build up of pressure as small as it seems to the atmosphere.Worked great as leaking was always a problem.That is what I will do .

Would not think pressure build up in primary could happen as the felt "seal" is there.

bchessell2 · Jul 25, 2022

I did it year ago on my other 750 as a final resort.It seemed to solve the problem.That was years before anyone tried to solve the pressure in the crankcase problem. I think it is puking at my seal so I will see while I am in there.
Thanks

Tornado · Jul 25, 2022

Yes i've had the crankseal blown in half from wet sumping pressure build up. First indication was oil over rear tire after riding a ways.

batrider · Jul 26, 2022

I use sealant on the inner (rough) side and grease on the outer cover. This allows easy removal. I don't obsess about a few drips here and there.

bchessell2 · Jul 26, 2022

After using the harder gasket the first time the next time I would use sealant between the gasket and outer time after time and it leaked slightly. My problem was removing that one and trying the new one from walridge .I found an original hard one in my junk.I am going back to the older used harder one and silicone the cover again .I will keep you posted.I found 1/4" material on amazon and I might give it a try.
Thanks again guys.

primary seal

bchessell2

WEM

Northton

Tornado

elefantrider

cliffa

Shelby-Right

bchessell2

Time Warp

.......back to the 70's.

bchessell2

Craig

Tornado

bchessell2

Tornado

batrider

bchessell2

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