Diablouph wrote:

Doesn't it make sense that having zero or negative pressure (vacuum) in the crankcase makes it easier to keep the oil inside the crankcase?

Agreed, but what I believe they are saying is that you should fix the leaks first, so you have solved the basic problem and then add the vac remedy.

I think there's a strong probability if you get rid of the crankcase pressure you'll find the leaks are gone too.

I seem to have stopped nearly all leaks that I used to have which were multiple. And I am using the timed breather off the left side. New gaskets with proper sealant (Hylomar is pretty good and doesn't stick). That said, I probably didn't get enough Hylomar on the crankcase flanges because when the Nort sits, I get a drip from the flange area. But it's several order of magnitudes better than it was. Nothing wrong with better sealant and if you can do, it a proper breather.

Dave
69S

pvisseriii wrote:

Guido wrote:

pvisseriii wrote:Guildo, Brevity its the soul of wit.

Quoting Shakespeare are we? Nice.
Didn't mean to be bossy.

Sorry Guildo. With the heat on our backs I better be careful what I say. I mean, christ man, it's sooo tempting sometimes I just can't help it.
My father always told me " Life without humour just wouldn't be very funny anymore."

Who's Guildo? Sounds too much like dildo, don't you think?
Once is a typo, twice is just plain silly.

You know, you're all right. Put in a breather and the leaks will lessen. Take it apart and fix the leak and then install a breather and it will not leak again, I would hope.
Nortons have a bad rap for being leakers only because they were originally made that way.
The parts that leak are:
The head, whether it's the head gasket, oil lines ,cover gaskets.
The tach drive.
The gear box cover.
The primary cover.
Or the swingarm pivot.
We as a community have come up with some nice mods to combat these issues.
Part of the fun is winning these battles against leaks which I gotta tell ya is as good as sex and just as satisfying.

Sorry Guido, corrections made.

My pre-Ms Peel Combat had 14 leak sites and was only reason I thought I'd go through her and learn the ropes with online hand holding. Oh brother if I'd only known then -...

Rocker pindle covers and bolts are another famous weeper.
Some the worse looking head mess can all come form fork seals.
Some 850's heads are cast porous to leak right out the metal pores.
Factory supplied chain oiler gave proper amount of oil to keep chain flushed out of wear particles but almost non existent now even in 'bone stock' ones.

If you gert it real clean , and dont put any in , and dont start it , she might not leak any .

The Breather trick , is it doubles the case volume ( ish ) improves timing side lube , and throw off .WITH
the breather in the Magneto Position ( What do the Dudes with Magnetos Do Then )

OTHERWISE , put a new gasket in the valve cover / s and clean the tacho Drive . I think throwing TWO 'O' rings
in there sometimes cures that . Too

." Pliobond " is pretty Good Gasket Cement .Its not pretty good getting it of though .( Std use in NZ in the 80s , oil tight )

Here's how I routed mine.

commando-head-barrels-studs-too-short-t11659-30.html?hilit=head studs

Thanks everyone for all the help! I am reading post and I am paying attention, I was just soliciting additional insight/ confirmation of the methods. Sounds like I have some researching to get to the bottom of all the other leaking areas that I have that have been previously discussed on the board.

I'm sorry that I haven't been on lately to post, I've got 3 and 1 year old girls at home so my daily free time is limited. I check in on the post at work, on my phone, but can't really post much.

Guido - it appears that your breather is coming from the timing cover, is this just a difference in the years of engines? My breather is low on the back of the engine on the magneto side.

Is the area in my photo below coming from the tach drive or is it another fix area?!


On the topic of crank pressure, I had an interesting encounter on my Aprilia 990 V-twin. I installed a catch bottle to get the residual oil from the breather, the catch bottle wasn't vented properly and I had all sorts of weird issues. Valve covers leaking, shifter seal leaking, water pump oil seal leaking and..... with lots of high RPM running the clutch started slipping (had a vacuum slipper clutch). Took a couple of week but tracked the issue down to the improperly vented catch can. Long and short of it, excessive pressure in the crank was causing lots and lots of leaks and other issues.

Yeah, if you don't vent the oil tank or the crank, things get strange. I put a catch bottle off my 69 from the oil tank breather that went into the air filter which was always leaking oil into the air filter and gearbox. Now it leaks into the catch bottle and no more leaks into the air filter. But this is an early bike. At least now I don't have oil dripping off the air filter onto the gearbox and down on the road. anymore. Life is good.

Dave
69S

kwoody51 wrote:Guido - it appears that your breather is coming from the timing cover, is this just a difference in the years of engines? My breather is low on the back of the engine on the magneto side.

Best guess is that you have a 72 model.

I wonder if the breather is clogged. Might be worth it to make sure. See if this video helps.



You should be be able to feel the breathing at the oil tank.

Thanks for the video! I'll have to check those things. Based on the condition of that bike I'm going to assume that is "normal" . Is this correct?

I actually took the hose off the tank and sucked/ blew through it, everything seemed OK. There is definitely a one way valve installed, I also confirmed that the breather form the engine is working.

I'm probably going to get the XS breather to replace the cheap looking plastic one that is there now.