Leaky valve covers

Kool_Biker · Jul 7, 2013

Torontonian said:
Just to add a thing to the list accumulating here ,overtightening the nuts to stop leakage warps the covers then things will get worse not better. Torque values are important here whatever they are. You absolutely need a reed type crankcase breather installed.

This is correct and I am fully aware. Thanks!

Kool_Biker · Jul 7, 2013

JimC said:
The XS reed type PCV valve does a lot better job and is nearly as cheap, $18. It's an inline installation, as well. Better yet is the CNW valve or Jim Comstock's valve. I tried the brake vacuum check valve, but it didn't work very long, if it worked at all.

The Yamaha valve seems bulky, and may be in need of mounting somewhere?

I have an Alton starter (good stuff, another story ..) and seemingly not that much space left?

Best, Aris

JimC · Jul 7, 2013

Kool_Biker said:
JimC said:

The XS reed type PCV valve does a lot better job and is nearly as cheap, $18. It's an inline installation, as well. Better yet is the CNW valve or Jim Comstock's valve. I tried the brake vacuum check valve, but it didn't work very long, if it worked at all.

Click to expand...

The Yamaha valve seems bulky, and may be in need of mounting somewhere?

I have an Alton starter (good stuff, another story ..) and seemingly not that much space left?

Best, Aris

If I recall correctly, someone here has mounted the XS valve on the backside of the timing case. Don't recall who or how. Been thinking about doing the same with mine. I do think the proper way is to mount the CNW (CNW part # 0500-08) valve. Supposedly, the closer to the crankcase, the better.

jseng1 · Jul 7, 2013

Aftermarket Silicone gaskets work well but they are too soft. The best option is to use extra hard silicone Part #5773T21 from McMaster Carr and make your own.

Seal the studs, use fiber washers under domed nuts.

Orings (oring store #s)
Tight oversize 3/32 x 3/4 ID O ring shift lever - work into place with dowel rod or use 5/8 ID Viton
Tranny kick quad seal 1 ID 1-1/4 OD (QR 214) viton
Tranny cam & shift pawl 3/4 OD x 3/32 viton (BV75113)

And for the paper timing cover & tranny gaskets - lay on newspaper and smear them with very thin layer of silicone and coat the metal surfaces with oil before installing for easy tear free removal (you can often re-use the gaskets).

Use "the right stuff" (Permatex #25229 or 25223) or Permatex moto seal #29132 for the cases & cylinder flange.

bmwbob · Jul 7, 2013

Oil wicks up the studs! Silicone the stud!

john robert bould · Jul 8, 2013

Oil as to be under pressure to leak "upwards ,discounting [capiliry effect] so with the commando the pressure inside the head is forcing oil out, check out my New post...head venting...if the followers have small or no chamfers, oil /air cannot return to the lower crankcase...been on about this with nortons for years!
My friends commando with no follower champfers just filled up with oil, leaks and smoke . As no one ever thought about this?

bill · Jul 8, 2013

if by chance some knucklehead has put an extra engine vent in the intake rocker cover it can slow the oil return and cause leaks.

john robert bould · Jul 8, 2013

By that do you mean the head return oil requires neg-pressure to suck it past the followers? I can see the logic in a good reed type crankcase vent, upward motion of pistons causing a crankcase vacuum, in turn sucking oil down from the head...

bill said:
if by chance some knucklehead has put an extra erankcase vent in the intake rocker cover it can slow the oil return and cause leaks.

Guido · Jul 8, 2013

Kool_Biker said:
JimC said:

The XS reed type PCV valve does a lot better job and is nearly as cheap, $18. It's an inline installation, as well. Better yet is the CNW valve or Jim Comstock's valve. I tried the brake vacuum check valve, but it didn't work very long, if it worked at all.

Click to expand...

The Yamaha valve seems bulky, and may be in need of mounting somewhere?

I have an Alton starter (good stuff, another story ..) and seemingly not that much space left?

Best, Aris

Try this location.

xs650-pcv-t11021.html

bill · Jul 8, 2013

if you have air trying to come up the oil drains for the head with a second breather on the rocker cover than it can impede the oil from draining done the small passages IE the tappets and drain hole on the intake side.

john robert bould said:
By that do you mean the head return oil requires neg-pressure to suck it past the followers? I can see the logic in a good reed type crankcase vent, upward motion of pistons causing a crankcase vacuum, in turn sucking oil down from the head...

ML · Jul 8, 2013

bill said:
if you have air trying to come up the oil drains for the head with a second breather on the rocker cover than it can impede the oil from draining done the small passages IE the tappets and drain hole on the intake side.

Bill, I don't know how you can prove that. Years ago, on my stock Mk2 850 before the reed valve thing took off I had persistent minor weeps from the motor despite careful attention to seals and gaskets. I experimented with fitting a 1/4" hose fitting to the inlet cover and it cured the oil weeps. I used a clear hose venting to a catch bottle so I could see what flow may occur, and there is a visible amount of wet vapour and you can feel the "puff" at the end of the hose.
There is definitely gas pressure up in the rocker chamber, no question about that. Does venting it retard liquid oil draining down the drain hole and pushrod tunnel? I seriously doubt it. After 80,000Kms I've never found anything that indicates I've got a build up of oil in the head. Motor nice and dry and a brand new XS reed valve given away as there was no point in using it.

Kool_Biker · Jul 9, 2013

Armed with all this newly acquired knowledge and support regarding my leaky valve covers, I will now pursue the avenue of lessening head air pressure.
I like the idea of venting via the inlet cover, the 1/4" pickup and vent tube to catch bottle. But where do you mount the catch bottle out of the way? Any pics? Please?
Alternatively, I would try the Yamaha PCV valve. But again, it seems rather bulky and my Alton starter installation has taken up what little precious space there was. Or does it? Any ideas?
Thanks to all for your support.
This is a great, highly focused forum.
Aris

john robert bould · Jul 9, 2013

This would require some testing, stranger things have happened , Velocette found [Geoff Dodkin] that at high rpm the return oil was centifuged of the flywheel, preventing it's return. he observed this by fitting a clear window on the timing cover, His modified drain was adopted by the factory.
Bact to commando, as the followers are a good fit in the cylinder follower bore, that small chamfer on the follower side is the only passage way past, i have followers with no chamfers, so whats the answer? head pressure blow's it out :?: vent this pressure and what :?: :?:

bill said:
if you have air trying to come up the oil drains for the head with a second breather on the rocker cover than it can impede the oil from draining done the small passages IE the tappets and drain hole on the intake side.

john robert bould said:

By that do you mean the head return oil requires neg-pressure to suck it past the followers? I can see the logic in a good reed type crankcase vent, upward motion of pistons causing a crankcase vacuum, in turn sucking oil down from the head...

Click to expand...

ML · Jul 9, 2013

Kool_Biker said:
Armed with all this newly acquired knowledge and support regarding my leaky valve covers, I will now pursue the avenue of lessening head air pressure.
I like the idea of venting via the inlet cover, the 1/4" pickup and vent tube to catch bottle. But where do you mount the catch bottle out of the way? Any pics? Please? Aris

The catch bottle I used is a plastic battery acid container that you get with a new motorcycle battery. It is rectangular, flat sides and fits very neatly alongside the 850 Roadster battery, between the left side tool kit cover. Blank off the screw cap, drill a tight fit hole for the inlet hose at the front which then goes into the container about 2cm. At the opposite end drill another tight fit hole for the outlet hose again inserted about 2cm.
Run the outlet hose up and over the rear of the battery compartment and down between the swingarm pivot and gearbox. I put the end of the outlet hose on the right hand side as a precaution to avoid any oily vapour getting on the rear tyre.
I find that with my motor in good condition, the catch bottle condensation amounts to about 100ml of liquid after 5,000Kms.

travelerjerry · Jul 9, 2013

Kool_Biker said:
Armed with all this newly acquired knowledge and support regarding my leaky valve covers, I will now pursue the avenue of lessening head air pressure.
I like the idea of venting via the inlet cover, the 1/4" pickup and vent tube to catch bottle. But where do you mount the catch bottle out of the way? Any pics? Please?
Alternatively, I would try the Yamaha PCV valve. But again, it seems rather bulky and my Alton starter installation has taken up what little precious space there was. Or does it? Any ideas?
Thanks to all for your support.
This is a great, highly focused forum.
Aris

Jeandr · Jul 9, 2013

Kool_Biker said:
BrianK said:

Those orange silicone valve cover gaskets work well. http://www.rockypointcycle.com/p-norton ... -5913.html

Click to expand...

Hiya
Does anyone know where I can get these (or similar) silicone gaskets in the UK and / or the EU?
Thanks
Aris

DIY don-know-this-good-idea-t3752.html?hilit=gasket

Jean

JimC · Jul 9, 2013

I chased oil weeps on my Nortons for years. It was like playing wack-a-mole. Replaced numerous crankshaft seals. Did the tach drive mod. Tried the vacuum check valve. Still oil on the outside. Finally installed a reed type crankcase breather. No more leaks or weeps. Had Norton equipped their bikes with a proper crankcase breather from the get-go I'd venture to say Norton would have a reputation of being oil tight.

Kool_Biker · Jul 10, 2013

ML said:
I experimented with fitting a 1/4" hose fitting to the inlet cover and it cured the oil weeps. I used a clear hose venting to a catch bottle so I could see what flow may occur, and there is a visible amount of wet vapour and you can feel the "puff" at the end of the hose.

Do you have a pic or schematic of exactly where you tapped the inlet cover (so as to avoid interference with the valve gear etc).

Cheers, Aris

ML · Jul 10, 2013

Kool_Biker said:
ML said:

I experimented with fitting a 1/4" hose fitting to the inlet cover and it cured the oil weeps. I used a clear hose venting to a catch bottle so I could see what flow may occur, and there is a visible amount of wet vapour and you can feel the "puff" at the end of the hose.

Click to expand...

Do you have a pic or schematic of exactly where you tapped the inlet cover (so as to avoid interference with the valve gear etc).

Cheers, Aris

OK, here it is. I end up changing from a brass BSP fitting to this early Commando 750 elbow. Goes in the middle so no interference to the inside, but you must use a right angle otherwise the hose gets kinked under the frame tube.

Kool_Biker · Jul 10, 2013

ML thanks, this is very helpful.

Aris

Leaky valve covers

Similar threads