Triumph Bonneville Electrical Woes


Motorcycle Classics tech expert Keith Fellenstein 

Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.

Electrical woes

Q: I have a 1976 Triumph Bonneville that I built into a bobber. The bike ran great before I stripped it down and rebuilt it. I ran my own simplified electrical wiring harness. It already had the electronic ignition system installed. I didn’t touch the engine. Now I do not get spark when I kick it over. The battery shows 13.5 volts, the resistance is good on both coils, and I have checked all the wiring for continuity and correct connection. When I turn the key on and off, I get spark at both plugs. I also installed a new key ignition switch. What’s wrong? — Perry/via email

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A: The quick and simple answer is that something is wrong with the wiring from the pickup coils in the points case. The black box is fine since you get spark when you turn it on and off. Remove the leads from the pickup coils in the points cavity and with the ignition on, touch the wire ends together momentarily. You should get a spark at the plugs when doing this. If you don’t, you have a problem with the wiring between there and the black box. If you do get spark that way, the problem is with the pickup coils.

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