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Does anybody know of an easy way to pressure test the engine? I just put it back together and wanted to make sure there were no leaks anywhere.

Take an old spark plug knock off the ivory and drill it out so that air can flow through it. Weld a hose nipple on it, and hook it up to a radiator pressure tester. Watch the gauge to see if it drops. Obviously you will need to plug the exhaust and intake up (I just used rubber plugs) and put the motor at BDC.

After that i spray the engine with soapy water to figure where the leaks are. You'll usually find some at your exhaust and intake plugs that you have to fix before you can check the base, head, crank seals etc. Also don't use too much pressure or you will pop your crank seals.

did you notice a suspect area when you were assembling the motor ? if so, it would have been best to correct it then. if it were me, i would fire it up...youll know soon enough if theres a leak, then you can worry about finding the leak.

Well it seems to run fine, need a little carb tuning but yeah my left side crank seal might be a problem, I had to get the case welded there, the guy did a good job but you never know. I just wanted to double check.

ya, I just use a 2 inch expanding rubber plug from home depot (with butterfly nut) and a pvc pipe cap with a a tire stem in it. plug it up, hit it with some pressure and listed. plus you can then just use a tire gauge to check for pressure losses.
maybe $6 in parts and about 30 minutes to get it all setup.

oh, I should probably explain, I leave the intake and exhaust manifolds on. use the rubber plug on the exhaust and the pvc cap to plug the rubber intake side.