Triumph Trident Boyer Ignition Troubles


| 4/25/2018 12:00:00 AM


Motorcycle Classics tech expert Keith Fellenstein
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Q: I recently purchased a classic Triumph Trident with wiring problems. The biggest problem at the moment is that the Boyer ignition doesn't compute to hook the coils in series. When tested, there is a voltage drop until near nothing on the last coil. Do I have coil problems? The other problem is the flasher that is hot all the time, the left turn signal works but not the right. — Gene McKillips/via email



A: I agree, at first glance wiring coils in series just looks wrong. The difference between points ignition and electronic ignition on the Trident is that the three sets of points fire each coil in sequence, while most electronic ignitions fire all the coils simultaneously. That's called wasted spark ignition, since in the case of the Trident only one cylinder will be on the compression stroke while the rest are on some degree of exhaust stroke. If you are still using the original coils, the problem with wiring all the coils in series is the voltage drop becomes a problem; the coils don't fire properly or at all. Where you once had three 12-volt coils, each wired separately, now you need — ideally — three 4-volt coils wired serially in order for each coil to receive enough voltage to fire properly. The Boyer instructions call for using 6-volt coils. If you make that switch you should be OK. I have to say that of all the bikes I own, an electronic ignition makes the most sense on my Trident. As to your left signal problem, grounding those old Lucas stalks is a common problem. The originals back in the day had a ground wire running from the socket to the metal pipe connecting them to the bike frame. Modern copies rely on the chrome plating on the plastic to ground the socket. As you might imagine, this fails over time due to corrosion and flaking chrome on the plastic.

DAVIDP
4/29/2018 11:37:26 PM

As for your turn signals. The units must be properly 'grounded.' The contact with the frame is not sufficient in most cases, the signal lamps must have both hot and common wires connected to them.


DAVIDP
4/29/2018 11:21:05 PM

What he says is absolutely true. While the system for twins can work with original 12V coils, the system for triples CANNOT. Sadly Lucas has stopped making the 4V coils which came with their Rita ignition. However, 6V coils are still available. These MUST be used with a 3-cylinder Boyer unit. The voltage readings you report could happen even with proper coils. In many years with a Rita on my T150 eventually the box would not fire the third cylinder. I never measured the coil voltages, just saw that the third cylinder was not firing, Replaced the black box and all was well again. If the box will not pass sufficient current the last coil in series will not fire.