I'm working on a 1979 motobecane 50v av7. I had recently put in new crank bearings and seals; the replacement crankcase gasket I got from treats didn't match well, so I had to cut it down to fit, and it was very difficult to keep aligned as I struggled to get the crankcase back together. The end result, this crankcase is leaking like a sieve on both sides near where it matches the cylinder.
Please advise; is there anywhere I can get a quality, properly fitting gasket from? Is there any method to ensure it is on correctly as I put the crank case back together? As many on here know, dismantling and putting together these crankcases is a major pain in the ass. I don't want to have to do this multiple times.