Post installation of Comnoz Sump Breather (71 norton)

I think there's a wise old saying: " Nortons are made for people with powers and abilities far beyond those of mortal men".

Or was that from an old TV show?

Anyway, I hope you get to the bottom of this puzzling problem. Don't let it beat you. Your work background should help.

My story is, when I got my bike as a basket case, I had recently been promoted to the position of Development Engineer for the company I had been with for some years.

I'm sure that my success in rebuilding the bike gave me more confidence in my job. At least, that's what I told myself while I was using the company's lathe to make bike parts.

And maybe the boss thought I was working back late on a project. Oh wait, I was!

With hindsight, there was probably a degree of beginner's luck involved.

It can't be easy to deal with a problem like this in heatwave conditions.

Don't take this as gloating, but it's winter in Sydney and the days are 60 - 65 degrees in the old money (fahrenheit). But our turn will come, they're predicting a hot summer this year.

Best of luck
Martin

Ive both been a mech and a network guy. You are following the right path
just perhaps slow to dig deeper sooner.
If the problem cannot be fixed quickly then you must cover each element
to be SURE they are not the problem. "Thinking" something is ok isnt
it, you must KNOW it is ok.
Not the end of the world if you have to pull the pump just a bother.
Not a waste of time either, doing makes you smarter.
Press onward good soldier!

Ok so I took the oil pump out. I inspected the gears and they look pretty good. At least I don't see any obvious issues like broken teeth etc.

I don't know how to check tolerances yet but I suppose I will figure that out real soon.

A couple things sparked my interest, the lid has a groove cut in it I suspect this is to allow lubrication to the gear faces?

Also I noticed the conical rubber seal is pretty funky looking.

Which side of the body needs to be sanded?

iceteanolemon said:

I don't know how to check tolerances yet but I suppose I will figure that out real soon.

Which side of the body needs to be sanded?

Click to expand...

Read factory manual section C25

Was there a paper gasket between the pump and the engine case. If no gasket or sealant then that may be the problem.

You can sand both sides of the pump to reduce the end play in the gears but that is not going to help your problem.

Reducing the end play may help keep it from wet sumping when parked but damage bad enough to cause a problem when running would be obvious. Jim

comnoz said:

Was there a paper gasket between the pump and the engine case. If no gasket or sealant then that may be the problem.

You can sand both sides of the pump to reduce the end play in the gears but that is not going to help your problem.

Reducing the end play may help keep it from wet sumping when parked but damage bad enough to cause a problem when running would be obvious. Jim

Click to expand...

Actually there was a paper gasket between the pump and case. I was afraid of finding nothing obvious.

If sloppy sand it, (I prefer resurface). You don't want it to be bound up in any way, though. From the pictures, it looks pretty good so be carefull what you play with.

The conical seal should ALWAYS be replaced when removing the timing cover. Does it look like it was misaligned?

Check the gear tip for notches or grooves. Inside the body should be check for the same around the arches.

Check these holes for abstructions in crankcase and timing cover for good measure.

Here is what I found when I had an oil returning to the tank problem.
A string of black silicon sealant stuck in the scavenge pickup hole.
Next time you drain the oil tank check the internal screen tube on the supply line for debris.

Make sure that breather hose you have running to the rear of the bike is not obstructed. Like a kink or a ziptie pulled too tight.
If the tank is not freely venting the crankcase will not vent either. Jim

On the old britts site I see #26 which sits between the feed valve and the conical seal. I did not have this on my pump.

I am ordering a conical seal now and noticed it. Any ideas? Should I throw anything else in?


http://www.oldbritts.com/1971_g3.html

iceteanolemon said:

On the old britts site I see #26 which sits between the feed valve and the conical seal. I did not have this on my pump.

I am ordering a conical seal now and noticed it. Any ideas? Should I throw anything else in?


http://www.oldbritts.com/1971_g3.html

Click to expand...

I don't know what number 26 is either. Maybe some kind of washer to get the correct squish on the rubber cone seal? Never seen anything other than the cone seal there. Jim

comnoz said:

iceteanolemon said:

On the old britts site I see #26 which sits between the feed valve and the conical seal. I did not have this on my pump.

I am ordering a conical seal now and noticed it. Any ideas? Should I throw anything else in?


http://www.oldbritts.com/1971_g3.html

Click to expand...

I don't know what number 26 is either. Maybe some kind of washer to get the correct squish on the rubber cone seal? Never seen anything other than the cone seal there. Jim

Click to expand...

OK so I ordered the washer from old britts anyways so I can see it at least.

Now about the pump itself....
I cut my own gasket from some gasket material I had grey stuff for the pump.

I ran the pump body across 1500 grit paper enough to make the surface shine. I then placed it together and now the gears turn with semi firm drag on the brass lid/cap end. I ran some oil through it and it is still firm to spin. Before it was spinning really easy like there was no drag on the gears.

Is this OK? From what I read on the manual it should drag but free up a little when you add oil, that it did but it is nowhere near as loose as it was when I cleaned it and rotated it before lapping it.

You're investigating all aspects of the oiling system now and that's a good thing, but I can't yet see an obvious reason for the failure to scavenge. The conical seal and the crankshaft seal downstream from it are vital to feeding oil pressure to the bearings etc, but don't affect scavenging. Even if the pressure side of the pump dumped all its output straight into the sump, the scavenge side should be easily able to scavenge the sump if all else is ok. That is , if the whole scavenge circuit is secure and not blocked. Not for long though, with no oil feeding the bearings.
A bit of slack in the pump increases the chances of wet sumping while standing, but I think it should still do an adequate job while running, otherwise we'd all be going through your ordeal.
I must confess though, my bike has not been used for some years and I'm trying to finish a rebuild in time for our spring.
So my advice is more theoretical than hands on.
Again, best of luck with it.
Martin

MFB said:

You're investigating all aspects of the oiling system now and that's a good thing, but I can't yet see an obvious reason for the failure to scavenge. The conical seal and the crankshaft seal downstream from it are vital to feeding oil pressure to the bearings etc, but don't affect scavenging. Even if the pressure side of the pump dumped all its output straight into the sump, the scavenge side should be easily able to scavenge the sump if all else is ok. That is , if the whole scavenge circuit is secure and not blocked. Not for long though, with no oil feeding the bearings.
A bit of slack in the pump increases the chances of wet sumping while standing, but I think it should still do an adequate job while running, otherwise we'd all be going through your ordeal.
I must confess though, my bike has not been used for some years and I'm trying to finish a rebuild in time for our spring.
So my advice is more theoretical than hands on.
Again, best of luck with it.
Martin

Click to expand...

Yeah as your thread dances around it I will hit head on... I am grasping for straws.

I am systematically checking everything I can check related to oil flow as I can and trying to find a culprit. Not finding a thing so far...

"Grasping at straws" is the very saying the came to me while I was out in the garage doing my thing but still pondering your problem.
I think we all feel your pain, if that's any help.
Cheers
Martin

Pump should spin pretty freely with no oil or wd/40 solvent and get tougher to spin with cold engine oil to watch it spit it out or suck it in various holes or turning direction. If ya put your tongue on the ports before over oiled, you should feel it suck a hickie in it or push a bubble past it. Basically yours should burnish up nicely after a bit of runing in.

#26 must be your own optional shim depending if under side gasket used or the thickness of the TS gasket or the thickness of end nipple.

Yeah as your thread dances around it I will hit head on... I am grasping for straws.

I am systematically checking everything I can check related to oil flow as I can and trying to find a culprit. Not finding a thing so far...[/quote]

It is probably something silly ,stupid, and obvious [if it were setting here in front of me.] Kind of like me updating the firmware in one of my cascaded routers without disconnecting the second router. [ oops]

It is obvious that you have had excess crankcase pressure due to the displaced main seal. It sounds like you still have crankcase pressure due to the fact the seal is still leaking into the chaincase. I have never seen a case were my reed breather did not produce a vacuum in the crankcase [even on a very worn engine]. That leads me to believe there must be a restriction somewhere in the venting system. Are you sure there is not a restriction in one of the oil tank nipples or a flap inside one of the hoses either leading from the breather to the tank or from the tank to the rear of the bike. I have never used a long hose to vent the tank. I have always used less than 6 inches with a mini-K&N filter on the end. You did say you had pressure in the tank that was causing the cap to leak. Maybe that long a hose needs to be larger diameter. [just a thought] Jim

Definitely grasping at straw on the long hose theory backing up to displace the seal. If nothing blocking the pressure paths and flapper flapping the right way then must consider blow by fault to fix. I've put my mouth over oil tank filler to see if it blew out easy enough, [shush up mine are feminine gender]. Ugh, i've also blown back up the long vent tube to verify the PCV was one way effective. So far never a drip out the vent so didn't look like I blew a seal in an oil spill. Don't know how to blow into crankcase but maybe the tach drive : )

comnoz said:

Yeah as your thread dances around it I will hit head on... I am grasping for straws.

I am systematically checking everything I can check related to oil flow as I can and trying to find a culprit. Not finding a thing so far...

Click to expand...

It is probably something silly ,stupid, and obvious [if it were setting here in front of me.] Kind of like me updating the firmware in one of my cascaded routers without disconnecting the second router. [ oops]

It is obvious that you have had excess crankcase pressure due to the displaced main seal. It sounds like you still have crankcase pressure due to the fact the seal is still leaking into the chaincase. I have never seen a case were my reed breather did not produce a vacuum in the crankcase [even on a very worn engine]. That leads me to believe there must be a restriction somewhere in the venting system. Are you sure there is not a restriction in one of the oil tank nipples or a flap inside one of the hoses either leading from the breather to the tank or from the tank to the rear of the bike. I have never used a long hose to vent the tank. I have always used less than 6 inches with a mini-K&N filter on the end. You did say you had pressure in the tank that was causing the cap to leak. Maybe that long a hose needs to be larger diameter. [just a thought] Jim[/quote]

Tonight when I get off work I am going to look closely at the breather tube feeding the oil tank and the one venting it. I will literally remove them and replace the vent with a catch bottle and short tube too.

Heh dont get me started on firmware! I am designing a cruise ship network with 37 IDF's and I need to automatically push firmware to them all without being there. I spend many of my days in the methodical approach!

network gear gives me the same break/fix joys but I just cant get my hands dirty like on the Norton! Nothing like the smell of gas and oil too!

I would rather get greasy.
I have 8 processors in the shop and 3 in the house to keep running. They can be a pain. I can't imagine keeping a ship full of electronic junk running. Jim