Crank Oil Seal leak

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Another thing to look at.

After running the engine at a steady 2500 rpm for 30 seconds or so there should be very little oil returning through my breather hose. Mostly air with small spatters of oil. If there is a lot of oil returning through my breather after running at a steady speed then you would want to find out why -either too much oil entering the engine or too little being removed by the scavenge pump. Jim
 
When I checked last, the oil pump was steady at first then the usual splatter of
oil and air. Your sump valve gave a steady flow and then very little oil just spit
a bit.
It is so satisfying to find a smoking gun but this hasnt happened yet.
Would really be nice if there was room for a better seal, like a two lip type.

As I mentioned previously, Im sure that this leak happens on lots of engines but
with an oil bath primary who would know?
Id say I get a tablespoon or less in 150 or so miles. With rearsets it is one bolt
to remove the primary cover and wipe it out. If it was 500 miles Id just wipe
and not be worried. But as it is, no, it needs to be sorted.

Ill be back with an update in a few weeks....
 
Onder said:
When I checked last, the oil pump was steady at first then the usual splatter of
oil and air. Your sump valve gave a steady flow and then very little oil just spit
a bit.
It is so satisfying to find a smoking gun but this hasnt happened yet.
Would really be nice if there was room for a better seal, like a two lip type.

As I mentioned previously, Im sure that this leak happens on lots of engines but
with an oil bath primary who would know?
Id say I get a tablespoon or less in 150 or so miles. With rearsets it is one bolt
to remove the primary cover and wipe it out. If it was 500 miles Id just wipe
and not be worried. But as it is, no, it needs to be sorted.

Ill be back with an update in a few weeks....

It sounds like you have things pretty much covered as far as oil scavenging.
I agree it would be nice if there was a better seal available, such as what is used in a modern two stroke.

Maybe you should try the all rubber seal. It will position the lip in a slightly different place on the crank.
I know a few people who have installed two OEM seals side by side and had success also.

Really it shouldn't leak at all with just the standard seal. I know a lot of people with belt drives that run completely dry.
Jim
 
Of all the seals of a Norton I firmly believe this is the one that has to be changed out every time the primary is apart. Others will differ on that point but it's cheap insurance and easy to do since you went to all the work to pull the primary. Never had one last more than 10 yrs. but now crankcase reed breather changes everything to goodly ride on stuff after 10 yrs. Just waiting but feel good about future life without pulses and flexings. Dry belt drive. :|
 
You might try spraying it down with contact cleaner, let it dry, dust the area with baby powder, fire it up and watch for the dampness to appear. I've found the leak on other stuff this way.
 
Couple of thoughts: first, the edge of the slot for the pulley woodruff key is awful close to the
seal area and hard pressed to see how you could get two seals in there. Which makes me wonder
if is a good idea to add shims to TS to shove crank outboard on the DS. I pretty much centered it.
Second, the idea of talc is a good old stand by but remember you are in behind the pulley. No pulley
no starting the bike. I suppose you could set it up for a quick run and tear down again. Bah. There
isnt any doubt in my mind at this point where the leak is. The three inner primary case to crankcase
bolts are in with blue loctite so it ain't them. The seal was a tight fit and potted with JB so I cannot
see a leak there. There is no leak at all from the TTI box and since the oil clearly comes from the
crank area....leaking crank seal.

The engine is oil tight and runs well. The thought of breaking the cases and rearranging shims
isnt on, winter season in sight or not.

At this point plan is to renew the seal, install with psychotic care and donate heavily to my local
satanic cult.

If that shows no improvement then Ill face a tear down.
Maybe....
 
Years ago, before I wised up about crankcase pressure, I bought a high dollar seal from Miller Bearing. IIRC, it was of some space age material other than the standard neoprene. Teflon, maybe. Anyway, it did reduce the oil leak, not entirely though. Once I installed a proper reed valve crankcase breather my primary case was oil free. I run a belt primary.
 
Hey maybe the seal was put in backwards ?

Oh my I'd sooner let on here I'd dated a sheep once. So we may never know for sure.

I'd try to see what surface leaked shaft or bore. hobot id for next seal is light oil wipe shaft, apply Hylomar around seal hole, wet seal rim with super glue, seat as usual then leave to set full up and hope for the best. An oily Commando is a obsolete long in tooth neglected thing to me and everyone else.
 
Hobot
I thought I had rattled on about all this to the level of list boredom!
I seriously doubt that the outer rim of the seal leaked. First, because it is a good tight fit and secondly because I JB Weld(ed) it in.
It aint leaking there.
It is leaking past the lip in some way. Since I saw no damage of the lip seal at all, I figured it was forced out in some way.

I promised to keep the list up to date on all this. It is necessarily in fits and starts.

Grew up with sheep. Dumb as stumps but dear things none the less. I shall admit any personal failing on this job :-O
 
Just go back to a primary chain drive using IWIS chain from Andy. You will never have to change the oil in your primary again. Just drain out the excess. No big deal.b
 
Yes but:
BNR clutch and belt light and wonderful. Maybe too light and too wonderful as no idea of how it stands up to road use.
Tomorrow Ill look into a "space age" seal. If anyone has a lead on that speak up please.
More than anything I want to know just what is causing the problem. You would think with Jim's sump valve that
Id be in good shape. Engine leaks not otherwise.
 
Onder said:
Yes but:
BNR clutch and belt light and wonderful. Maybe too light and too wonderful as no idea of how it stands up to road use.
Tomorrow Ill look into a "space age" seal. If anyone has a lead on that speak up please.
More than anything I want to know just what is causing the problem. You would think with Jim's sump valve that
Id be in good shape. Engine leaks not otherwise.


why don't you try using some old fashioned oil to see what happens. See new thread I created.
Dereck
 
I mistakenly thought Miller Bearing was national. Unfortunately, they are located in Florida, only. Any good bearing supply house should be able to give you some choices of crankshaft seals. You can give them the I.D. and O.D. and running environment and no doubt, they will have some suggestions. I'm not familiar with any of the "super" seals our Norton suppliers offer, but you can bet these are stock items in most bearing supply houses.
 
Onder said:
Who is the manufacturer?


Are you asking who the seal manufacture is? If so, I don't recall. It was some 15 years ago I bought it. IIRC, it was a common manufacture, such as SKF, formerly Chicago Rawhide (CR). You really need to speak with a knowledgeable counter person at your local bearing supply house.
 
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