850 Cylinder head leak

swooshdave · Feb 6, 2021

Schwany said:
That is for the most part why I didn't remove my shade tree engineered steam punk PCV plus catch can plumbing on my Atlas 750 engine, and install a JS reed valve in its place. There is crank case pressure being released at the old magneto hole location, but it's got a lot of oil mist in it and I have to keep an eye on the catch can. I would have the same issue with a reed valve, but it would be harder to clean out.

One other thing I did to reduce crank case pressure even further is put a 5/16ths inch hose barb fitting in the left side exhaust valve cover and one in the intake valve cover. I run the hoses back to a T fitting and then into a small vented prescription bottle catch can. The valve cover vents also made a noticeable difference in top end performance on my motor. The not so great thing about that modification besides ruining the valve covers is vacuum is very low with the 2S cam, so cold starts require a lot of leg. I don't have any valve cover or other engine oil leaks. I've been using the same hard as rock valve cover gaskets forever.

Milky goo in the high end prescription catch can. It has a foam filter and a bunch of holes in the top. The hoses use to go out to the bottom of my rear fender, but the guys on 916 Ducs used to complain about the white goo getting on their face shields. Street hooligans.

Milky goo is water in your oil.

Usually it’s from condensation. How it getting there in you bike?

Schwany · Feb 6, 2021

swooshdave said:
Milky goo is water in your oil.

Usually it’s from condensation. How it getting there in you bike?

Shows up more during the colder months. If it is a problem my motor doesn't know about it, or it would have blown up by now. Probably caused by short rides and cold weather condensation more than anything else.

I don't think about it much, since it's done it ever since installing the 2S cam and putting the valve cover venting in. The oil tank doesn't have water in it, if that is what you are thinking. Never any water in the oil pan when I change oil. I'd have to pour water in the oil tank, and I'm not that far gone yet. Getting closer every day though.

jbruney · Feb 6, 2021

That's Duc bait. Attracts the hell out of them.

swooshdave · Feb 6, 2021

Schwany said:
Probably caused by short rides and cold weather condensation more than anything else.

The milk stuff is emulsified water in the oil. Water blended with water makes for poor oil characteristics.

Maybe longer rides, warm up the bike more or keep the bike warmer?

olympus · Feb 7, 2021

Schwany said:
That is for the most part why I didn't remove my shade tree engineered steam punk PCV plus catch can plumbing on my Atlas 750 engine, and install a JS reed valve in its place. There is crank case pressure being released at the old magneto hole location, but it's got a lot of oil mist in it and I have to keep an eye on the catch can. I would have the same issue with a reed valve, but it would be harder to clean out.

One other thing I did to reduce crank case pressure even further is put a 5/16ths inch hose barb fitting in the left side exhaust valve cover and one in the intake valve cover. I run the hoses back to a T fitting and then into a small vented prescription bottle catch can. The valve cover vents also made a noticeable difference in top end performance on my motor. The not so great thing about that modification besides ruining the valve covers is vacuum is very low with the 2S cam, so cold starts require a lot of leg. I don't have any valve cover or other engine oil leaks. I've been using the same hard as rock valve cover gaskets forever.

Milky goo in the high end prescription catch can. It has a foam filter and a bunch of holes in the top. The hoses use to go out to the bottom of my rear fender, but the guys on 916 Ducs used to complain about the white goo getting on their face shields. Street hooligans.

For the un initinated..on the 750 Atlas photo it has Rocker feed drilled vertically into the head... was this moved to the position we know & love due to the head steady mounting.??

kommando · Feb 7, 2021

swooshdave said:
Milky goo is water in your oil.

Usually it’s from condensation. How it getting there in you bike?

When you burn 1 gallon of petrol in your combustion chamber you get nearly 1 gallon of water produced. Hopefully that all goes out the exhaust, where on cold mornings on a cold engine you see the steam coming out the silencer. On a warmed up engine should be a small amount of steam entering the crankcases past the rings as blowby, also the oil being hot enough so when in the tank the moisture breathes out into the air filter and back into the engine. So milky goo is either from short runs, so the engine is not getting hot enough, or excessive blowby and the oil tank cannot get rid of the moisture fast enough.

Schwany · Feb 7, 2021

kommando said:
When you burn 1 gallon of petrol in your combustion chamber you get nearly 1 gallon of water produced. Hopefully that all goes out the exhaust, where on cold mornings on a cold engine you see the steam coming out the silencer. On a warmed up engine should be a small amount of steam entering the crankcases past the rings as blowby, also the oil being hot enough so when in the tank the moisture breathes out into the air filter and back into the engine. So milky goo is either from short runs, so the engine is not getting hot enough, or excessive blowby and the oil tank cannot get rid of the moisture fast enough.

My oil tank venting is not plumbed back into the air filters.

It's the short 9 mile test runs that generate the goo. I'm a fair warm weather rider now. Last time I thought I'd go out for 75 miles, the sky started getting black and sprinkles were falling, so I tuned around. Now it's too cold. I got all that riding in the freezing cold snow and rain out of my system with off road bikes decades ago.

The goo shown was 4 test rides or more worth of goo in the vessel. I get a brown/green goo in my catch can, since it is right off the magneto cover plate. That doesn't bother me either. Just the way motors work that aren't PCV plumbed perfectly.

Edit:
I'd run a better scavenging PCV setup on my hot rod if my 2 into 1 exhaust wasn't running right under the sump drain. Easy fix with the down pipes now available for the P11, but I'm not sure I want a sedate looking chrome exhaust, and I would have to weld up mounts to hang the silencers from. Not on my short list yet.

N0rt0nelectr@ · Mar 16, 2021

Gerard Rowley said:
A fellow Norton owner has asked me to have a look at an oil leak from the cylinder head on his 850
He has just had the engine rebuilt by a mechanic but they can’t work out why it is leaking. I cleaned the oil away and started the engine and in about 30 seconds quite a steady stream of oil is coming from under the two nuts in the front of the head the ones that join with the studs from the barrel. I think that this has been discussed on here before but can’t find it. Is there a fix for this and where would the oil be coming from

I had a similar issue on my 74 Mk2A. I replaced the head gasket and it was still leaking so I pulled the head again. I had heard about an issue with the front studs that screw into the cylinder so I pulled them. When putting a light down into the stud hole I could see light in the push rod tunnel. I think what was happening was that the oil was working its way up the stud and leaking out where the nut holds the head in place. I used some high heat JB Weld that was like a putty. Worked it into a pea size ball and put it down inside the stud hole making sure that none of it worked its way into the push rod tunnel. Reinstalled the stud with red Loctite and let it cure over night. No more leak.
John in Texas

jseng1 · Mar 17, 2021

Schwany said:
That is for the most part why I didn't remove my shade tree engineered steam punk PCV plus catch can plumbing on my Atlas 750 engine, and install a JS reed valve in its place. There is crank case pressure being released at the old magneto hole location, but it's got a lot of oil mist in it and I have to keep an eye on the catch can. I would have the same issue with a reed valve, but it would be harder to clean out.

One other thing I did to reduce crank case pressure even further is put a 5/16ths inch hose barb fitting in the left side exhaust valve cover and one in the intake valve cover. I run the hoses back to a T fitting and then into a small vented prescription bottle catch can. The valve cover vents also made a noticeable difference in top end performance on my motor. The not so great thing about that modification besides ruining the valve covers is vacuum is very low with the 2S cam, so cold starts require a lot of leg. I don't have any valve cover or other engine oil leaks. I've been using the same hard as rock valve cover gaskets forever.

Milky goo in the high end prescription catch can. It has a foam filter and a bunch of holes in the top. The hoses use to go out to the bottom of my rear fender, but the guys on 916 Ducs used to complain about the white goo getting on their face shields. Street hooligans.

That's a lot of plumbing you have going on there. Why not just install a reed valve and get rid of all the other breather lines? Run the reed valve outlet to the oil tank and you're done. I have one reed valve on mine and no leaks whatsoever.

Schwany · Mar 17, 2021

jseng1 said:
That's a lot of plumbing you have going on there. Why not just install a reed valve and get rid of all the other breather lines? Run the reed valve outlet to the oil tank and you're done. I have one reed valve on mine and no leaks whatsoever.

Thanks Jim. Yeah all that plumbing is kind of redamndickulous to say the least.

I don't think I have enough 1/4" flat stock laying around to make another magneto hole cover. I'll have to dig around some more and see what I have.

I do get condensation out of the timing cover in my catch can, so the condensation would be going back to the oil tank with the reed valve. None of the motor exit lines go to the oil tank. The oil tank is vented to the atmosphere. Anyway, I'll think on it.

All that plumbing isn't really to prevent leaks. It's the only way I could get any top end out of the motor after removing the stock cam with the timed breather setup. Without all that crank case ventilation plumbing the motor is a real turd with the 2S cam in it. I probably did something wrong though. Doing things wrong is my super power.

850 Cylinder head leak

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