Timing cover oil weep

texasSlick · Jul 12, 2021

My Atlas timing cover has had an oil weep since the first time I removed it to check cam chain tension .... way back in the early 60's.
It does not drip, per se, but if I run my finger under the cover at the lowest point (which is always flooded with oil), my finger comes up wet with oil. Wipe it dry, wait a few days, and there will be oil again.

As far as I can tell, the cover is flat, no nicks or gouges on the cover or timing side crank case.

I have tried all sorts of gasket material and sealers. The weep is minimal with JS Eng. fiberglass reinforced silicone gaskets or with 1/32 inch synthetic cork, but still there nevertheless.

Anyone else having (or had) this problem? Any suggestions?

Slick

CanukNortonNut · Jul 12, 2021

Could it be that you have porosity through the timing cover? You could try loctite 290 and the activator 7649
Cheers,
Tom

Schwany · Jul 12, 2021

Banjo fitting from timing cover to the rockers can do it. I've found I have to tighten that fitting more than feels comfortable. Fortunately I've never stripped the threads going into the timing cover when cranking it down. Just a thought.

Bodger · Jul 12, 2021

texasSlick said:
My Atlas timing cover has had an oil weep since the first time I removed it to check cam chain tension .... way back in the early 60's.
It does not drip, per se, but if I run my finger under the cover at the lowest point (which is always flooded with oil), my finger comes up wet with oil. Wipe it dry, wait a few days, and there will be oil again.

As far as I can tell, the cover is flat, no nicks or gouges on the cover or timing side crank case.

I have tried all sorts of gasket material and sealers. The weep is minimal with JS Eng. fiberglass reinforced silicone gaskets or with 1/32 inch synthetic cork, but still there nevertheless.

Anyone else having (or had) this problem? Any suggestions?

Slick

Tighten it to the point where you're afraid of stripping the cover screws. (I take no responsibility for what that point is.) Mine weep or don't weep depending on the phase of the moon. It's important to fix each leak because that way you never have more than one more to deal with. To be serious though, it is possible the oil is coming from the junction block or even from the feed on the oil tank and migrating down the bottom of the oil line.

acotrel · Jul 12, 2021

It is the oil pressure indicator. When it stops, the motor goes bang.

texasSlick · Jul 12, 2021

@Schwany: I have low pressure rocker feed from return line to oil tank, but a good observation no less. This is in the category put forth by Bodger below.

@Bodger: Good points regarding oil junction block or oil feed line. I will check them out more closely, but I think I have those places oil tight. Regarding tightening the cover screws ... I do tighten until 1/8 turn from stripping

. Seriously, last time I had the timing cover off, I used a 1/32 synthetic cork gasket, and tightened screws until the gasket squeezed out 1/16" all around cover, or estimated 50% thickness reduction. How do you do better than that?

@acotrel: Sorry, not an oil pressure indicator .... this is a static weep, but your comment deserves a smiley face.

Deets55 · Jul 12, 2021

Slick,
Call Cometic and see if they have any of those gaskets on their computer. They use to make them up by copying an original (supplied by customer) at no extra charge. They have a lot of Commando stuff, none of it is on the website, you have to call them up. I have them on my MKIII primary, cylinder base and valve covers. Reusable, they don’t leak And no special tightening instructions
Pete

Torontonian · Jul 12, 2021

Some T.Cover gaskets were thin. Some later ones thicker. Perhaps you should check this ?

acotrel · Jul 13, 2021

texasSlick said:
@Schwany: I have low pressure rocker feed from return line to oil tank, but a good observation no less. This is in the category put forth by Bodger below.

@Bodger: Good points regarding oil junction block or oil feed line. I will check them out more closely, but I think I have those places oil tight. Regarding tightening the cover screws ... I do tighten until 1/8 turn from stripping . Seriously, last time I had the timing cover off, I used a 1/32 synthetic cork gasket, and tightened screws until the gasket squeezed out 1/16" all around cover, or estimated 50% thickness reduction. How do you do better than that?

@acotrel: Sorry, not an oil pressure indicator .... this is a static weep, but your comment deserves a smiley face.

I liked it. Any British bike which does not leak oil is very suspect.

Fast Eddie · Jul 13, 2021

acotrel said:
I liked it. Any British bike which does not leak oil is very suspect.

I sometimes say that.

And I also sometimes say that there’s no excuse for leaks.

Which one I say at any given time depends on how incontinent, or leak tight my bikes are at the time

phippsy · Jul 13, 2021

I found putting talcum powder or chalk round the suspect leaks helps to pinpoint the suspect

Fast Eddie · Jul 13, 2021

phippsy said:
I found putting talcum powder or chalk round the suspect leaks helps to pinpoint the suspect

We’re still talking about motorbikes right ??

Seeley920 · Jul 13, 2021

acotrel said:
I liked it. Any British bike which does not leak oil is very suspect.

Just as well you don't race then. Any bike which leaks oil will be turned away at scrutiny, and double checked in the warm up area and on the grid

maylar · Jul 13, 2021

The first place that my new Commando leaked oil from was the tach drive. Fixed that with the oil seal mod that replaced the O-ring. The second leak was from the timing cover gasket. Fixed that by using Allen screws instead of the cheese headed slotted screws and Permatex gasket goop. That was 40 years ago.

RoadScholar · Jul 14, 2021

When I find leaks I clean up all the surfaces with Simple Green and wipe dry. Next I use a Kleenex twisted into a wick and dab around the high possibilities and gradually work down to the point where the oil collects and drips; shouldn't take long to find the leak point.

Schwany said:
Banjo fitting from timing cover to the rockers can do it.

Bodger said:
To be serious though, it is possible the oil is coming from the junction block or even from the feed on the oil tank and migrating down the bottom of the oil line.

These are good possibilities, but the copper sealing washers should be replaced or at least annealed. Over torquing might end up being expensive tuition , tread lightly here. Allen fasteners can be better engaged then their slotted cousins.

I am about to reinstall an Atlas timing cover and discovered that the seal between the oil pump and the timing cover is different from both the pre-MK3 and the Mk3; it is smaller and has slightly less diameter if you used a Commando pre-MK3 seal the timing cover won't want to seal without pressing your luck by exceeding the 87 in/lbs specified for 1/4" fasteners; I'll admit to going up to 92 in/lbs. My plan is to use, discreetly, some modeling clay to see what the new seal has to deal with to bridge the pump to the cover.

Best.