new engine oil leaks

[moonlake3]

Just got my new engine running. This is my second build. I had plenty of problems getting it to start the first time. Finally got it going. Never was quite sure what was wrong.
Took it for first breakin ride. leaking oil at head gasket and where the muffler attaches to engine. Maybe oil mix wrong? Also vibrates a lot after it gets past mid range speed. Vibrates and sounds like it's going to let loose. Sure a lot different than my first engine, I ran the first engine over a year. Used it a lot.

AND the 2 front mount studs broke. They were smaller diameter than my other engine. Any thoughts on this. What a bummer. I guess I'll try to get the broken pieces out and drill and tap to lager size.

I know this is 3 problems, but after searching forum for hours, thought I would post for some directions or thoughts. thanks to all that help on this forum

 

[Kevlarr]

What oil mix are you using and make sure the spark plug is tight.

 

[BarelyAWake]

This;

What oil mix are you using and make sure the spark plug is tight.

and...

leaking oil at head gasket and where the muffler attaches to engine.

This is quite common with new engines and it's usually a sign of improperly torqued fasteners, no big deal at all. The head should be torqued to 120-144 inch lbs/10-12 foot lbs, if it still leaks - disassemble and examine the gasket seating surfaces for irregularities, if you think that's the cause - lap the head (sand) with wet/dry 300gt sandpaper on a piece of glass (so it's perfectly flat) - this too is quite common.

vibrates a lot after it gets past mid range speed.

Usually a sign of a too rich mixture (four stroking/firing every other stroke) it could also be that your engine is simply still breaking in... check spark plug coloration (black = too rich, white = too lean) and adjust the carburetor's needle clip settings to suit (up, away frm pointy end = leaner & down = richer), yer lookin for that coffee/coco tan/brown of a proper mix - and/or just ride the bejabbers out of the thing.

the 2 front mount studs broke.

Usually a sign of excessive movement/excess vibration - yet not always from the engine itself, check the rear sprocket for alignment & centering by raising the bike off the ground and with the clutch in, turning the rear wheel and watching for wobble, chain "walk" (off to one side or the other), and most importantly - seeing if the chain gets tighter & looser as the wheel spins. That's really common and is caused by improper centering of the rear sprocket and I suspect causes quite a few mount failures.

A disproportionate amount of vibration is caused by the stock "rag joint" rear sprocket mount - check our vendors for sprocket adapters, it's a night and day difference

 

[moonlake3]

I'll remix my oil/gas mix. I'll check the head torque. That is where the oil is leaking, and new exhaust gasket. I'll also check plug for richness.
I'll have to work with the front mount sduds breaking off. I'm gonna try to go to one size bigger. Maybe I didn't have the new motor fastened solid enough. Had to improvise on the front mount. I used a piece of rubber. After reading here it seems the solid mount is the way to go. This is the same bike as first build. Just replacement motor. thanks