Oil leak into outer timing case

[PeteRae]

Morning....
there shouldn't be any oil between the inner and outer cases apart from a wee bit of dribble and misting.
Check that all the fixing bolts/screws are the correct length and thread holes are clean. I've had two lower fixing bolts that were too long and had been forced in and burst through into the gearbox allowing oil to seep along their threads.....and also damage casings!!
Both below the gearshift, one to the right and one to the left.
Pete.

[PeteRae]

Also, please have a look at the photos everyone.  I found these in the bottom of the outer cover, amongst all the thick oil.  I think they might be from the ratchet.  I guess i just get a new one, undo the nut, and change the ratchet?  Is it that simple? What might have caused this?

Hi Phil,
they certainly look like teeth from the kickstart ratchet. They can break off if the kicker is jumped on when stuck. The teeth on the quadrant and the ratchet don't always mesh initially and folk can maybe jump on the kicker rather than rocking the bike.
You will need a windy gun to take the nut off otherwise you'll have to stop the mechanism from turning with rags or a similar bodge.
Oh and get a new lockwasher too....
Only know cos I'm doing exactly the same at the moment...
Pete

[Colin SS90]

Hi Phil,
I assumed you had an external leak, or is it that you did not expect to find oil between the inner and outer covers and that is what you thought was a leak.
Earlier B40's had a different set of inner and outer timing covers which did not allow gearbox oil to be inside the outer cover.
Sorry for the confusion. Colin

[Phil C]

Thanks to everyone for your help so far.To clarify and recap, I have a slight leak from the bottom of the outer casing joint, out onto the garage floor (well, drip tray.) I wasn't expecting to find much oil inside the outer casing, but found more than a mugful ( see photos at start of discussion.) If I'm understanding people correctly, I'm getting contradictory information: someone says there should be a  oil in the rear part of the outer casing, up to the same level as in the gearbox, whilst someone else says there shouldn't be any (except a slight dribble or misting). So I'm in a bit if a dilemma.  Help!   Phil

[Phil C]

I do wonder though: if there is not supposed oil in the outer case, what is the hole in the inner cover below the quadrant for?  Phil

[DAVE BRADY]

Hi,

Sorry for 'gasket' in my earlier post read sealant. A gasket would affect the clearances in the gearbox.

B40s with a distributer have an inner and outer timing cover/case and there should be no oil in the outer part.  I think this is held on by only 3 or screws as it is a cover rather a load bearing case.  The later side point B40F does not have the thin outer cover but rather a case that forms part of the outer gearbox and houses the clutch mechanism etc.  This is held on far more securely with more and longer screws.
The rear part of this is in effect part of the gear box and as such has oil in it.  The front part should have no amount of oil in it but forms part of the breather system in that the crank case vents in to it and then there is the small breather tube that comes out near the ignition wires.  As this acts as a condensation chamber there may be a bit of oil in there similar to the photos.

Dave.

[Phil C]

Thanks very much, Dave.

So between front and rear is just jointing compound on the face of the dividing wall?

I don't see where on my inner casing the crankcase vents into the outer (see earlier photo)?

Phil

[JulianS]

For the engine breather outlet check the lug where the clutch cable fits, I would expect an outlet there, usually would have a tube attached.

The outer cover should have an oil seal for the kickstart shaft to assist keeping the gearbox oil in.

[DAVE BRADY]

Hi Phil,

There is a hole forward of where the advance/retard unit is.  When the crank is in the correct position this hole lines up with a hole in the idler gear and lets the crank case pressure out. 
It is necessary to seal the rear part completely to contain the gearbox oil. You should  do the front part as well then the pressure from the crankcase will go through and out the proper place and not cause a weep at the front part of the case.

Dave.

[Phil C]

Yes I see the outlet, it's the inlet from the crankcase I don't see.  Phil

[JulianS]

The inlet should be top left of the inner cover near the cable grommet. Explore with a length of wire and it should be revealed.

[DAVE BRADY]

Hi Phil,

Right arrow points to location of timed breather hole from crank case.  Left arrow point to open exit breather hole.  Sorry about small copy of your image.

Dave.

[Phil C]

The inlet should be top left of the inner cover near the cable grommet. Explore with a length of wire and it should be revealed.

Isn't that the outlet?

[Phil C]

Hi Phil,

Right arrow points to location of timed breather hole from crank case.  Left arrow point to open exit breather hole.  Sorry about small copy of your image.

Dave.

Thanks Dave but I can't see your arrows (may be my poor colour vision coupled with small dark photo I gave you.)
Here is another pic - should I be able to see the inlet breather from the crankcase in this view? (poorly lit photo again, sorry.)
Phil

[DAVE BRADY]

OK try this.  I have lightened your image and used a white arrow. 

Dave.