front mount-bolts loose & noisy

[bigbee]

with about 3 hours on a new 48cc engine a pinging noise started at medium to hi rpm, sounded like pre-detonation or a loose wrist pin, not a good sound. after several days and allot of different cures that didn't work it turned out to be the front engine mount was loose.

 

[Dockspa1]

front mount

I ended up putting a spot weld on the bolt head to the frame.
I had the oversized frame.
Good thing you found it before twisting the engine!
Doc

 

[gone_fishin]

if i re-mount my engine for whatever reason, i line it up by eye & i do get it right by the book. but...it has a mind of it's own & always settles in a few degrees from where it should be, during those few miles it sure does get to clanking. after i let it set, i re-tighten the mount bolts and it's good to go, no more clank.

FYI-i check my mount-bolts about every 20-30 miles...1000 miles on the originals.