i have an mc21 with an odd problem it has just been rebuilt new main bearings gaskets etc it has even had new carb gaskets fitted the bike runs great but only over 2500 rpm below that it wont run on rear cylinder the mechanic that doing the work for me put a strobe light on it and below 2500rpm the timing is moving so we have an eletrical problem pickup coils pgm3 possibly can anyone help me out here has anyone had a problem like this

The pick up coils suffer with the wires chaffing as they enter the coil. Make sure the outer insulation is in good condition.

I would also check the change of the battery, the stator including the reg rec.
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If I have to take the carbs off once more...

thanks for the reply but i am a bit dum can you explain what the stator and reg rec is