crankshaft oil seal

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I don’t think he started it Swoosh, pool of oil under the bike after being on the bench for 5 months (in first post).
 
After 45+ years of wet clutch Norton ownership I came to this conclusion. If I know I'm not going to start my bike for an extended period of time, I drain the oil out of it. If I'm going to ride the dinosaur once in a while, I try to start the bike every 5 days or so to help keep the oil in the oil tank and reduce wet sumping. If you do that, after you do all the work you are going to do, you might not feel like you need to open the primary up again and replace the crankshaft oil seal. If you don't, you might see a little oil under the bike now and again. It's part of the charm of owning and riding an English antique.

I've owned a lot of motorcycles that did not leak any oil. My Norton is not one of them, but it is one of the only ones I have left in my garage.
 
I am seriously considering getting the AMR mod before they stop offering it.

Back to the seal, if you try to start the bike and it's wetsumped you can invert the seal. Then if you let it sit for 5 months when the crankcase fills up it will leak.

Just spitballing ideas out of stuff I've read here over the years.
 
if you send out the timing cover have the also do the pressure relief mod also .

swooshdave said:
I am seriously considering getting the AMR mod before they stop offering it.

Back to the seal, if you try to start the bike and it's wetsumped you can invert the seal. Then if you let it sit for 5 months when the crankcase fills up it will leak.

Just spitballing ideas out of stuff I've read here over the years.
Click to expand...
 
Full circle to 9 options to deal with wet-sumping:
1. One way anti-sump valve. If it fails, so does your engine.
2. Manual on/off valve in oil supply. If you "forget" to open it and run the engine. It fails.
3. Manual on/off valve in oil supply with integrated ignition power interrupter. Sounds great?
4. Install the Comstock sump reed valve to pump all of that oil back in the oil tank before the crank seal blows out.
5. Send the timing over to AMR for a conversion to stop the oil draining. Some say this doesn't work for long.
6. Buy a new one or rebuild the oil pump so it won't pass oil so easily. Good luck with that.
7. Drain the sump any time the bike sits 2 weeks or longer. pour that oil back into the oil tank. That sounds like fun.
8. The hell with it. Just start the engine with a full crank of oil. Blow out the crank oil seal. Live with the oil leaks. La la la la la
9. Start the engine once a week to keep it alive and happy and the oil pumped back to the oil tank where it belongs.
 
swooshdave said:
I am seriously considering getting the AMR mod before they stop offering it.

Back to the seal, if you try to start the bike and it's wetsumped you can invert the seal. Then if you let it sit for 5 months when the crankcase fills up it will leak.

Just spitballing ideas out of stuff I've read here over the years.
Click to expand...

If you have access to a mill it's a fairly striaghtforward job, all you need is a .325 endmill to a depth of about .5". The oil pump seals are easily added as well (thanks for the tips on that Kommando) with a .5" endmill, service the pump while you have it apart (again, not challenging), finally, plug the OPRV hole in the timing case and drill a new one that vents to the timing chest... voila!
 
acadian said:
If you have access to a mill it's a fairly striaghtforward job, all you need is a .325 endmill to a depth of about .5". The oil pump seals are easily added as well (thanks for the tips on that Kommando) with a .5" endmill, service the pump while you have it apart (again, not challenging), finally, plug the OPRV hole in the timing case and drill a new one that vents to the timing chest... voila!
Click to expand...
Yer average Norton owner doesn't have a mill or the skills to operate one. Huh? Get this back to what "regular" people are able to do. Come on.
Is this the racing Norton forum. If so, say so. Wow, I thought this was about a leaky crank seal on a standard Commando.
 
lazyeye6 said:
Full circle to 9 options to deal with wet-sumping:
1. One way anti-sump valve. If it fails, so does your engine.
2. Manual on/off valve in oil supply. If you "forget" to open it and run the engine. It fails.
3. Manual on/off valve in oil supply with integrated ignition power interrupter. Sounds great?
4. Install the Comstock sump reed valve to pump all of that oil back in the oil tank before the crank seal blows out.
5. Send the timing over to AMR for a conversion to stop the oil draining. Some say this doesn't work for long.
6. Buy a new one or rebuild the oil pump so it won't pass oil so easily. Good luck with that.
7. Drain the sump any time the bike sits 2 weeks or longer. pour that oil back into the oil tank. That sounds like fun.
8. The hell with it. Just start the engine with a full crank of oil. Blow out the crank oil seal. Live with the oil leaks. La la la la la
9. Start the engine once a week to keep it alive and happy and the oil pumped back to the oil tank where it belongs.
Click to expand...

4. Sump thing works to an extent. Too much oil and you may not be able to spin the crank enough to get it started. If you do get it started the sump will clear quickly enough.

5. My brother had the AMR thing done years ago. He wasn’t that impressed and still had issues. Back then they just did the cover and rebuilt the pump. Since then they noticed some people having issues so they starting doing the OPRV mod. Apparently not everyone had a questionable OPRV hence the hit or miss. Anyways when my brother saw they now did the OPRV he contacted them and even though it had been MANY years they offered to do the ORPV mod for free (he just paid shipping). They also offered to inspect the oil pump they had rebuilt but it was perfect. That’s pretty impressive customer service. Anyways, this winter I’ll have them do both my bikes.
 
lazyeye6 said:
Yer average Norton owner doesn't have a mill or the skills to operate one. Huh? Get this back to what "regular" people are able to do. Come on.
Is this the racing Norton forum. If so, say so. Wow, I thought this was about a leaky crank seal on a standard Commando.
Click to expand...

As long as you have a good pillar drill with a tight spindle it can all be achieved at home.

The trick is to have some rod the same diameter as the original holes to use to locate the workpiece before clamping in place.
 
Last edited:
I have Jim's bottom located sump valve. It will pump out the sump quickly. However my seal still leaks. From the preceding comments looks to me that the oil gets "pressed" out with the first turn of the crank what with all that oil in the sump. The seal does not appear to get folded over.
Starting today Im going to drain the sump upon return from riding and see how that goes. Well I will when I get my bloody
seat back from the upholsterer anyway! Blasted lockdown nonsense....stunning weather and I want my Norton !
 
My 850 engine would leave a pool of oil under itself if left to stand for several weeks. Basically, this was when the sump was full of oil. Oil must have filled to the point it found a weak spot. BUT it didn’t leak at all if used frequently, and the sump kept empty.

SO... I’m thinking that expecting the sump to remain oil tight when full might be an ask to far? Maybe there was nothing wrong with Maylar’s oil seal in terms of remaining oil right in normal use? Maybe it just leaked cos the sump was full. Maybe it would have been just fine if he’d drained the sump and run the bike?
 
Fast Eddie said:
Maybe it just leaked cos the sump was full. Maybe it would have been just fine if he’d drained the sump and run the bike?
Click to expand...

Bingo. It started leaking about a week ago. I've since drained what looks to be about 2 quarts of oil from the sump, obviously it was high enough to get to the seal. I've owned this bike from new and would never start the motor after 5 months without draining it first.

I have the XS650 breather and during riding season there is absolutely no oil leak. Start the engine weekly and wet sumping is averted. Next winter I'll drain the tank before putting the bike up for the season.

The seal was loose in the crank case. A new seal with some JB Weld and Robert will be my uncle.
 
lazyeye6 said:
Full circle to 9 options to deal with wet-sumping:
1. One way anti-sump valve. If it fails, so does your engine.
2. Manual on/off valve in oil supply. If you "forget" to open it and run the engine. It fails.
3. Manual on/off valve in oil supply with integrated ignition power interrupter. Sounds great? IS GREAT!
4. Install the Comstock sump reed valve to pump all of that oil back in the oil tank before the crank seal blows out.
5. Send the timing over to AMR for a conversion to stop the oil draining. Some say this doesn't work for long.
6. Buy a new one or rebuild the oil pump so it won't pass oil so easily. Good luck with that.
7. Drain the sump any time the bike sits 2 weeks or longer. pour that oil back into the oil tank. That sounds like fun.
8. The hell with it. Just start the engine with a full crank of oil. Blow out the crank oil seal. Live with the oil leaks. La la la la la
9. Start the engine once a week to keep it alive and happy and the oil pumped back to the oil tank where it belongs.
Click to expand...

#3 for me, all day and any day :cool:
 
swooshdave said:
We’re trying to find the cause of the seal failure and there are multiple possibilities.
Click to expand...
No, we're not. The seal failure is obvious - it's not tight enough in the case bore. Please reread post #1.
My questions have been answered - the best seal is the rubber type, and some JB Weld will help it stay in place without leaking.

Thanks to all who responded.
 
I've never had a problem with that seal leaking. Every time the primary is off you replace it. A light smear of Hylomar on cleaned aluminum seal , outer contact does it. All Nortons need a reed crankcase breather to prevent oil seepage worries. But then new worries arise. Enjoy.
 
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