Help My Bultaco has no spark

[nzambon]

I have a 1975 Model 137 Bultaco 250 ALpina it is a US model. I rewired it to spec the brake lite switch is new and the resister is good. My problem is soon as I hook the ground up I lose spark what Iam I missing. :bang:

 

[Bultaco206]

Did you have spark before you wired the brake light?

1) Unhook kill switch.
2) Check ground on upper coil.
3) Do you have the OEM Leonelli switch box? Those are rust magnets.

Take the brake light switch out of circuit and see what you have.

 

[nzambon]

Bultaco 206 yes I have spark until I hook up taillite ground. The leonelli switch box is rust free and good shape. ? The high beam indicater lite wiring shows blue/white wire as being ground and red power but its oppisant of the rest of the wiring aaaagh.

 

[Bultaco206]

OK, then your 'new' ground sounds like it's causing a dead-short. I only ever had one Alp with lights (M99) and I don't remember the switch having its own ground. Hmmm...