Britbike forum Forums Thread Like Summary - Primary repair woes...drip drip

Trying to tackle the drip on a 68 a65t primary case/crankcase not cover

On close inspection it has been repaired by weld. Skillfully as the threads for the chain case are uniform with the rest and the repair contains the primary chan adjuster.

Problem is it's ever so finely not true when checked with a straight edge
Thus the drip. Other than tearing the whole thing down and building it up and skimming on a mill is there anything that can be done in situ besides globbing gross amount of yamabond or silicone. I don't mind a drip or 2 now and against for territorial establishment but a steady puddle 😔

Or is there a lower priced belt drive setup out there for the non racer?

DA, my engine is apart right now and I would be happy to measure my primary cover screws for you...

but not tonight; it's too flippin' cold in the garage. It's supposed to be considerably warmer tomorrow. FWIW, I think there are only two different lengths, but I'll double-check.

Another thing to check is that there is no gasket cement pushed down into the holes. I "exploded" one of the screw bosses once, forcing the screw into a clogged hole, and had to have it welded.

When you file the JB Weld, use a wide, long flat file, long enough to span the low area. It should be fairly fine, single-cut; I don't know my file terminology; you may have to go shopping in the hardware store if you don't have such a file.

As you've probably gathered by now, I've been down the road you're on right now, as have many other of the responders I'm sure. So bear up, the tunnel does have an end.

Why not try using a thick silicone gasket like This One which is 3/32 thick and should take up any gaps when compressed.

I would also run a large flat file over the lower gasket surfaces to remove any high spots and also lightly countersink the screw holes.

Also worth manually turning a drill in the screw holes to remove any accumulated gunge which could prevent the screws from bottoming.

I like to use fiber washers under the drain and level screw heads as they compress and seal a bit easier than copper washers.

Some thots, have you opened up the cush drive and looked for internal wear on the spider and end plate?
If the tensioner blade is not down to the metal re use it, a great deal of the initial bed down is the chain making its path through the slipper material.