bike wont start!

[Josh_rs]

okay so i swapped my engine out because the clutch wouldnt work and found a cheap aprilia mx50 engine so went for that was told it was in good running order. bike is stock derestricted, tried to start it on an 82 main jet started like twice, couldnt keep the revs up (wot) then just before it died it backfired, tried to start it again wouldnt start and kept backfiring, went down to 78, wouldnt start, plug was looking black and wet, the plug is sparking, tried a couple of other plugs, went down to a 65 jet (really lean) and it started again but couldnt keep the revs up, and just before it died it backfired again. and now it wont start, plus im nackered after running with it trying to start it, havent bought a kickstart yet

[RS_Patrick]

Sounds like ignition timing problem... take the flywheel of and check the stator plate and inspect the wires coming from the coils that threy got no damadge.