Re: No spark, Tomos, Coil or CDI?

mk /

What model year do you have? After about 1985, the ignition no longer depended on the lights. After about 1996 they went to a CDI system instead of points. The CDI is very simple, only 3 parts. There's a coil under the flywheel, the CDI box (with integral HT coil) mounted on the frame, and the kill switch.

If you have the CDI system first disconnect the kill switch to rule it out. The black wire from the engine should go only to the CDI box. Check that the CDI box and engine are securely grounded. If still no spark, test the flywheel coil for continuity (black wire to ground)-- and you should also get some AC voltage on the black wire to ground when turning the engine. If the flywheel coil is OK it must be the CDI box, that part is the usual problem.

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