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Tech Corner

Technical Q and A for classic motorcycle maintenance and repair.

Triumph Motorcycle’s Turn Signals Not Blinking

 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, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail  with “Keith’s Garage” as your subject.  

Triumph Motorcycle’s Turn Signals Not Blinking 

Q: I’m having some trouble with the turn signals on my Seventies-era Triumph motorcycle. The right signal works most of the time, but the left signal seldom works. Everything looks like it’s connected properly in the headlight bucket. Where should I look next? — Mike Myers/Lawrence, Kan. 

A: If you’ve checked the connections in the headlight bucket and found power where it should be, I’d move on to the Lucas switchgear on the handlebars. Experience has taught me these have a variety of ways of not working. Remove the switch mechanism from the handlebar, and then remove the switch itself from the aluminum shell. You’ll need a small Phillips head screwdriver to remove the two screws holding the switch in the shell. Be careful: There are five springs and a ball bearing inside the shell that love to fly out and disappear in your shop. Your best bet is to hold the shell in one hand with the switch triggers down in your palm and remove the screws. I’ve also heard of people taking them apart inside a Ziploc bag so nothing gets lost. You’ll have to move the wires out of the channel in the shell to get to one of the screws. Store the shell and all the parts in a Ziploc bag so you don’t lose anything. Now you have the actual switch still attached to the wires. Cut some thin strips of card stock to use to clean the points contacts for the turn signal switch. Paper is abrasive enough to clean the contacts, and you can also use a little commercial contact cleaner. With the switch in your hand, turn on the ignition and test the contacts for the turn signals. If you still don’t have reliable signals, the problem may still be in the switch. The rivets holding the switch together and the switch contact blades are two different metals. Over the years and with exposure to moisture, they build up corrosion. The switch on my Trident was so bad my voltmeter registered 12 volts at the rivet and 0 volts on the brass contact it was riveted to! I had to solder-bridge the rivet to the brass. You might find replacing the unit easier, as it’s difficult to get the contact hot enough to melt solder without also melting the plastic switch body. MC