Ok, so still working on this 75 mx400. I couldn't get the bike to start up at first, and determined the guy who owned it before me hooked up the kill switch wrong. I cut the switch and voila! Fired right up. Only problem now is no way to kill (besides the obvious stuff). I bought a new switch, and hooked it up. Now, once again no start up. I cut the wire again and it started up like it should. Diagnosis? The CDI is very old and pretty nasty. Could it be something in there? Any thoughts of course are appreciated! Thanks for your help.

Ok, so still working on this 75 mx400. I couldn't get the bike to start up at first, and determined the guy who owned it before me hooked up the kill switch wrong. I cut the switch and voila! Fired right up. Only problem now is no way to kill (besides the obvious stuff). I bought a new switch, and hooked it up. Now, once again no start up. I cut the wire again and it started up like it should. Diagnosis? The CDI is very old and pretty nasty. Could it be something in there? Any thoughts of course are appreciated! Thanks for your help.

All the kill switch does is ground out the ignition coil, when the switch is off there should be no path to earth (chassis) and vice versa. You could rig up any switch to do this, connect one side to chassis and the other to where the original did connect to., or you could stop the bike using the ignition key which does the same thing

That is what I did, except i put the ground on the coil ground. There is not an ignition on this bike. I will try to just connect it to the frame and see what happens. Thanks!

That is what I did, except i put the ground on the coil ground. There is not an ignition on this bike. I will try to just connect it to the frame and see what happens. Thanks!

Its the Black / White, ground that and the engine stops.