Kinroad xt50-18 with loncin 125 engine

[Barnsy]

Hi everyone, i have recently fitted a brand new loncin 125cc engine to my kinroad, i have replace the old carb and manifold for a new one, which came off a 125cc bike. i have also replaced the coil for a performance coil, and the 50cc cdi for a 125 race cdi. the bike works great and pulls like a train until the throttle is about 1/3 or 1/2 of the way open. when it reaches this point the bike just wants to stall. the main thing i have noticed is that my rev counter is showin way to many rev's for what the engine is running at.

I kind of think the problem is some thing to do with the rev counter, or the magneto.

Any Help Will Be Appreciated