Oil In Primary

Yesterday I was going to take the 850 Commando for a ride. I found the oil a quart low and got curious.I filled the oil tank and rode around the block. The clutch was dragging. After further investigation, I found that the primary case had about a quart of engine oil in it. After removing the cover , cleaning and running the engine to sling all residual oil off the components, I have not found the culprit. The oil could only come from three bolts that hold the primary cover to the engine case or the crankshaft seal. I have confirmed that 2 of the three bolts are tight and will have to strip the case of the Alton Stator and the clutch and chain to inspect the other bolt and seal. I am tempted to remove and reseal all three bolts and replace the seal to be safe. I am concerned that the clutch fiber discs are contaminated an may need replacement. Obviously, I will clean them. Anybody have any thoughts or advice? Thanks in advance for any help.

The clutch will be fine once you clean it, but you obviously need to locate the source of oil entering the primary. I would probably clean the chaincase again and prop the bike on the side stand and check back the next day for signs of dribbles. My bet is the main seal.

Check primary/crank seal as well as the lower front inner case to crank mounting bolt. For the seal, I finally cured the weeping with a double lipped seal sourced from a supplier:

http://www.oringsandmore.com/oil-shaft- ... -for-1-pc/

Also,... even a seal that should be in good enough shape to do it's job stopping oil from migrating to the primary case, might not work if your crankcase breather is blocked which would increase the pressure on that seal and all the gasket joints on your engine.... so check your breather to make sure it's operating correctly...

... and if you don't have a reed valve breather, you should think about installing one... Jim Comstock, who posts here, makes a reed breather that bolts up to your crankcase in place of your drain plug. It eliminates the design flaw that most parallel twins of that era have in common... crankcase pressure generated oil leaks...

If you suffered a major wet sump condition (virtually entire oil tank leaked into sump) you may have "burped" out the main seal.

Slick

Mine did that. Started it after a major wet sump without draining the sump. Filled the primary and was running out everywhere, also smoking out the exhausts. Drained the primary and no problems, didn't mess with the clutch, it functioned okay.
As said the seal must have burped because it seems to be functioning okay afterwards. Did the AMR mod and no more wet sumping.

It's comm for oil to weep past the deal if it wet dumps & sits. I learnd this after mine sat for a while. I always check to make sure by unscrewing the primary case level plug and letting any excess oil drain out if the bike is been sitting for a while and wet sump at all... If it's written consistently this never happens.

I always drain the crankcase if the bike has been sitting long enough to wet sump. After stripping the primary, we found that the front chain sprocket was touching the seal and would spin it in place. Leak found. Seal replaced. A machinist is going to relieve some material from the back side of the sprocket. Just another day in the life of Norton ownership.

Tis about time you all employed someone to convert your timing cover so oil does not leak down into your crank cases. The system is fail safe....i.e if it fails it fails allowing oil to pass rather than shutting off the oil supply to the motor.
Unfortunately many owners think the oil pump is knackered and buy a new one...ALL gear oil pumps allow oil to pass the gears but many of you do keep friends of mine making money building batches of new pumps along with servicing old ones for which I feel certain my friends offer a BIG thank you............ Actually with the slight variation in the new machined pump bodies and new gears each pump is selectively built and tested and in doing that there is very little profit to be made and i often ask why they bother with them with all the other greater profit work they have building up...

J. M. Leadbeater said:

Tis about time you all employed someone to convert your timing cover so oil does not leak down into your crank cases. The system is fail safe....i.e if it fails it fails allowing oil to pass rather than shutting off the oil supply to the motor.
Unfortunately many owners think the oil pump is knackered and buy a new one...ALL gear oil pumps allow oil to pass the gears but many of you do keep friends of mine making money building batches of new pumps along with servicing old ones for which I feel certain my friends offer a BIG thank you............ Actually with the slight variation in the new machined pump bodies and new gears each pump is selectively built and tested and in doing that there is very little profit to be made and i often ask why they bother with them with all the other greater profit work they have building up...

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Many if not most of us already have the timing cover mod in place, unfortunately it only seem to slow, rather than completely prevent the problem

Either keep riding it or drain the crankcase when you don't. No more trouble than draining the primary and pre-empts the issue rather than just fixing the symptom. Most I've found in mine after a long layoff is about 1/4 of a quart.

t7275tr said:

I always drain the crankcase if the bike has been sitting long enough to wet sump. After stripping the primary, we found that the front chain sprocket was touching the seal and would spin it in place. Leak found. Seal replaced. A machinist is going to relieve some material from the back side of the sprocket. Just another day in the life of Norton ownership.

Click to expand...

Never heard that happening before, but glad you decided to pull your primary apart to find the problem, its not that big of a job to pull down, but with a E/S kit in there would be a bit longer to pull down but worth the troubles to fine and fix a problem than to be worring about it all the time.

I had a mate turn up once with a blown main seal and he was freacking out about it, before he knew what was happening I had his Norton in my shed as I had a spare seal and started ripping into it, he was surprised how quickly I did the whole job, but the best part of the job was drinking the case of beer he brought for doing it, it ended up being a great day in the shed with a good mate.

Ashley

Best mod. I've ever done on my '73 850 is the oil shut-off valve with ignition interlock, no more wet-sumping!

Best mod. I've ever done on my '73 850 is the oil shut-off valve with ignition interlock, no more wet-sumping!

Details Dave?

I got the valve from a chap in the AMC owners club, it was many years ago so I don't know if he still does them. It's just a lever operated valve,( much like a washing machine valve) with a bracket and microswitch attached, I do have a photo on the lap-top but cannot remember how to post photo's! You might find more info if you search out some of my old posts on here, i'm fairly sure I did post a photo of it some years ago,
regards,
Dave.