Originally Posted by Biker Mike
When I first installed my engine, it ran out great. As time and a few miles went by, it started missing at higher RPM's. I noticed oil coming from the exhaust gasket around this time as well. My question is, would a blown exhaust gasket effect high speed RPM? I have not torn into one of these engines yet and do not know what the reed valves look like (any pic's of valves?).
Change the plug too, NGK B5HS!... move the carb needle to LEAN (needle down, c-clip at top)Double check all wire connections, I like to use solder,(crimps vibrate loose)!
The exaust leak is NOT the cause, my whole pipe fell off in the street going home once & I lost the nuts, so I rode it home with NO PIPE & the bike never ran faster!!!
Another thing I do is adjust the gaps between the spinning magnet & the mag coil to make them equal. I noticed on a few of the engines that I bought the mag coil was WAY OFF. (almost touching)
I don't know if it helps?... but why not?
Also try a 25:1 mix & then a 30:1, see if that helps?