oil leak

For the last couple of months I have been chasing an oil leak and for the love of me I can't figure out where it is coming from.
The center stand has oil dripping off of it and the cradle has oil on it in front of the stand.
The drain plugs are tight with new gaskets. No oil on the oil hoses to or from the engine or oil filter.

After talking to a friend who suggested I use a florescent dye I picked up the dye and black light from NAPA. $27 which isn't so bad. Put it only in the oil tank and started the bike to let it circulate.

What I found puzzles me. Looking under the bike the streaks of the florescent dye was evident but not where I expecting it. It was on the drive sprocket and a few links on the bottom of the drive chain. The shield that is cast into the inner primary had it on there too. What the heck!
First thing that came to mind was that the crank seal was leaking so I removed the level plug and only a drip of ATF came out. Removed the outer primary to check the bolts holding the inner primary on and they are tight.
The chain oiler was blocked off a long time ago and there isn't any oil on the outside of the tank that would indicate a crack.
I expect it might be something simple that I'm overlooking.
I'm open to any suggestions.

John in Texas

What/where does the oil tank breather vent to?

And which year/model are we talking about?

My Atlas breather comes off the oil tank and terminates at the chain guard near the gearbox. Oil mist (before I put in a scrubber) would do exactly what you describe. The idea is the oil mist would lubricate the chain, but the speed of the chain only slings it off to gather on, and drip off, the shield behind the primary inner cover (that is why the shield is there).

Slick

texasSlick said:

My Atlas breather comes off the oil tank and terminates at the chain guard near the gearbox. Oil mist (before I put in a scrubber) would do exactly what you describe. The idea is the oil mist would lubricate the chain, but the speed of the chain only slings it off to gather on, and drip off, the shield behind the primary inner cover (that is why the shield is there).

Slick

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Can you describe your scrubber? I have a Mercury which mysteriously leaks oil as described.

The oil tank has to breathe somewhere. Where is that breather tube going? And yeah, which model?

I too had a leak like you describe, what I found was 3 leaks in total, 1 was coming from the alternator wire grommet, although new it wasn't the best of fits, No 2 was coming from the outer pri cover, even with a new rubber band & it being flat, I found this to be the worse one, when it was bolted up, you could rock the cover slightly front to back, a good bead of silicon has sealed it, & lastly the bottom of the outer pri cover is a little porous or has a hairline crack at the front just above the ex pipe, I have not tried to seal this yet(too busy) but I am going to try some loctite 290 (I think) to try & seal it.

HTH Paul.

It'll be from the swinging arm spindle.
Dave

Without seeing it -I might guess the bottom of the oil tank has a crack around the mount. Jim

My bad it is a 74 850.
Not having the original air box I ran a vent hose out to the end of the frame loop. I checked along that hose and didn't find and oil on the outside.

John in Texas

comnoz said:

Without seeing it -I might guess the bottom of the oil tank has a crack around the mount. Jim

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I had the mount removed and only use the two at the top with a gas tank pad under it for support. It had originally cracked around the bottom boss and knowing that was a problem area had it removed and a plate welded in. Still, I will pull the tank and do a pressure test on it. Maybe the weld failed, let you know.

John in Texas

I pulled the oil tank and did a pressure test on the tank. No leaks!
Did take the time to clean out the inside of the tank.
Now it is back to square 1.

John in Texas

John in Texas,
Check the Oil junction block off the RH engine case at the gasket or the washer. They sometimes leak and leaves a scent post marking of where your Norton roams. Mine is leaking there and I haven't fixed it yet. Just another place to look.
Cheers,
Thomas
CNN

CanukNortonNut said:

John in Texas,
Check the Oil junction block off the RH engine case at the gasket or the washer. They sometimes leak and leaves a scent post marking of where your Norton roams. Mine is leaking there and I haven't fixed it yet. Just another place to look.
Cheers,
Thomas
CNN

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I will look there. Always something isn't it!

Still after the leak. I have done a pressure test on the tank and can see no leaks. When I had the tank off and doing the pressure test I could see no leaks around the banjo fitting. When I put it all back together and of course filled the oil tank, I noticed a bit of oil around the banjo. I haven't started the bike so the leak isn't under pressure. Drained the oil and checked the gaskets for the banjo and they looked damaged with dings in them. Don't have and new gaskets so I went to Auto Zone to see what they might have and found an assortment of copper gaskets. I was thinking that copper would be as good as the aluminum if not better. Had to buy 2 assortments to get the 2 gaskets I needed, can't win. Had to relieve the outer most gasket a little so it would fit over the filter but it is a nice fit. Still leaks! Damn!
Removed the gaskets and annealed them. Only put enough oil in to cover the filter and let it sit over night. You got it, still leaks.
I have some of the correct gaskets coming and will give you an up date.

Maybe Jim can give me some insight on the aluminum vs copper gasket thing?

John in Texas

N0rt0nelectr@ said:

Still after the leak. I have done a pressure test on the tank and can see no leaks. When I had the tank off and doing the pressure test I could see no leaks around the banjo fitting. When I put it all back together and of course filled the oil tank, I noticed a bit of oil around the banjo. I haven't started the bike so the leak isn't under pressure. Drained the oil and checked the gaskets for the banjo and they looked damaged with dings in them. Don't have and new gaskets so I went to Auto Zone to see what they might have and found an assortment of copper gaskets. I was thinking that copper would be as good as the aluminum if not better. Had to buy 2 assortments to get the 2 gaskets I needed, can't win. Had to relieve the outer most gasket a little so it would fit over the filter but it is a nice fit. Still leaks! Damn!
Removed the gaskets and annealed them. Only put enough oil in to cover the filter and let it sit over night. You got it, still leaks.
I have some of the correct gaskets coming and will give you an up date.

Maybe Jim can give me some insight on the aluminum vs copper gasket thing?

John in Texas

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I prefer the copper gaskets. If you anneal them with a propane torch they will be softer. I have been known to paint them with high temp aluminum paint also.

I have seen cases where the seal surface on the tank was not perpendicular to the threads. It caused the washer to crush more on one side than the other. Installing the banjo and bolt with no washers could reveal a gap on one side.
A little careful work with a 180 grit DA pad stuck to a flat bar cured it.

Thanks Jim, I will check that out. I have annealed the gaskets but I will do it again and try the aluminum paint trick also. Maybe its time to break out the magnifying glass and look at all the sealing surfaces, can't hurt.
Odd that after 40 years I'm having this sort of issue? Always something!

John Ebert
Granbury, TX

Use Dowty Bonded Seals - SB026 7/8" ID - Oil tank banjo x 2.
Ta.

I will go on line and see if I can locate a dealer. Where do get yours?

Going to take the tank back out and lap in the banjo to both the tank and filter. Don't know if this will improve things but couldn't hurt.

Thanks to all who have given me ideas of how to proceed.

John Ebert
Granbury, TX

needing said:

Use Dowty Bonded Seals - SB026 7/8" ID - Oil tank banjo x 2.
Ta.

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http://www.mcmaster.com/#93783a046/=yhay8b A bit spendy at $3.44 each, but they can take up quite a bit of non-parallelism, and are reusable!

Nathan

I have removed the oil tank again. Cleaned the sealing surface and lapped in the banjo to the tank and filter. Annealed the copper gaskets and lapped them in on a glass plate. Cleaned the bike of any leaked oil and I have put just enough oil in the tank to cover the filter. Now we wait.

If this doesn't work I will contact a local bearing and seal shop and see if they stock the Dowty bonded washers.

Again, thank you all for your help and insight.

John Ebert
Granbury, TX