MZ/MuZ Riders

Hi, I've just bought a XTZ engine from a Supermono racer to fit in my Mastiff but the ignition timing is out and it backfires through the intake. I also fitted the MZ generator assuming that the flywheel is the same because they look identical but would like to know if there are any differences between the XTZ and MZ ignition timing?
They have similar but not identical numbers on their CDI units so I'm assuming they must have different flywheels despite them looking similar. Also as anyone got an Idea if the mods for Supermono series racers that may affect the engine's compatability with a standard CDI Unit?
Big questions I know but I'm at my wits end!

PS The engine shows no sign of modification outwardly an looks unmolested.

Ignitech is the answer for your Ignition box problem, that way none of the differences, (if any) really matter. You can just program it for your new motor and leave flywheel and all the rest intact..........

Thanks for the advice but such ignition devices are rare and very expensive in the uk so its possibly cheaper to get another engine. Ignitech does sound like the answer tho so if I can find the cash I will get one.

STOP PRESS: Further investigation implies that the mechanical valve timing is out!

Err no Ignitech is actually quite cheap - been using them for 4 years now, you would have to communicate by email but they are good guys, contact them here http://ignitech.cz/english/aindex.htm

What happened to the original.? Just swap the parts.