help / advise needed on 640

[Allegro]

My son (Allegro jnr on forum) 640 cuts out for no reason. We have checked terminals, side stand switch bypassed,and went through wiring aswell.  Speedo goes dead bike cuts out. Restart and go again. Happens intermittently 

[igeorge]

I had a issue like that on mine - I cured it by spraying (lots of) cleaner into the ignition switch, and it never came back...

Worth a try:)

[Malibu]

Me three!

Opened up and cleaned ignition switch... fixed!

[Allegro]

Great fanx, will try.

[Sprocketbek]

I agree that it could be the ignition switch, they tend to give problems, but my 640 also cut out intermittently and the fault was very hard to find.

On the sidestand and clutch switches there are diodes (behind the headlight, look on the wiring diagram) which are still in the circuit despite the switches being bypassed. In my case, the terminal was crimped on too hard (or had a sharp edge) and the copper wire was just about cut through.
After fixing that it never gave trouble again.........touch wood!

[JMG]

A long time ago mine did it too but it was the wire on the battery side that supply power to the ignition.

[Allegro]

Thanks, will check that again.