So I started taking covers off the engine and ran into this ugly mess. I knew the weld was there but not the crack. Pretty sure someone lost a chain because the countershaft cover was also cracked. I put oil in it and turned it to make sure oil would be over the crack, if it is actually getting to the crack. No oil, but off course that's not under any pressure. Looking at the epoxy, it looks like they covered the crack but didn't  put a stopper hole and the crack traveled down until it found one. So just put JB Weld and hope? or is that useless. I saw a case on ebay but I was really hoping I would not have to split cases. The case would have to be split for more welding wouldn't it? If I smack that bolt with an impact driver, that might be the end of it. The only thing that is a crack is line running from the epoxy to the top of the bolt, it doesn't run out from the bottom of the bolt, all those other things that look like possible cracks aren't.

Here is the weld.  That is NOT a crack running down from the hole in this pic


This pic shows the  crack running out the epoxy through the top of the bolt hole.








 

Epoxy is not part of the casing… aluminum welding may be the fix… but aluminum is as it is… one piece and it’s good..
It’s time to find a mate for the other side…
Sneezles61

So hard to tell cracks on cases...  I several similar lines in your pictures...  are you sure it's a crack? 

Maybe drain oil, hook up a bicycle pump to transmission vent, pump up to a psi or two and spray area with soapy water and see if it leaks?

MarkT that’s a great idea!!! I’ll remember that one for sure 

I know with old magnesium VW motors you can use a gas torch to heat the suspected crack up a little and it if is cracked will temporarily open up with the heat. Maybe this can be tried with aluminum too?

Great tricks MarkT, never thought of doing that. If it were me though--just me haha--I'd leave it alone & Not run the third screw in the cover either as always breaks out there when the chain breaks & bunches up.

The line from the epoxy is a crack, I can compress it and see it move, none of those other lines are cracks.

My local shop has TIG welded 2 of mine that were broken in the same area. The engine can stay in the frame but it is easier if the engine is removed.

Looks like yours was. Just may need a little more.