WR426 missfire in mid rev reange

a mate just rebuilt his bike, piston kit, new cam chain etc and the 3 inlet valves.

Just prior to the rebuild it had the missfire in the mid range, if you really gassed it it would 'break through ' and go hard, but just going up the revs it was missing quite badly at what i'd guess about 4000rpm... it was put down to the poor condition of the valves .....

we checked all the jets etc, the bike starts a lot better than before (new valves) and feels better/stronger while not missfiring.

the carb has had some crap in it and the next job is to inspect it and clean it out.. the hotstart plunger was gunky, but has been cleaned...

does it read as a fuel problem or electrical?

My 426 did the exact same thing until I got it jetted properly. Smooth as can be now.

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