SPARKY STUFF

Following last month’s letters, I would like to reassure Mr Miller that his Triumph Thunderbird 6T crankshaft is indeed suitable to accept the non-dynamo chaincase. On this year of Triumph twins the engine shock absorber is contained in the clutch. He would only need to replace the rotor with a suitable spacer.

I own and rebuilt the engine of my Triumph T100 recently. I also helped a friend rebuild the engine on his 1957 Trophy TR6 and, while rebuilding it, I noticed it had a replacement crankshaft which was stamped 6T ( Thunderbird). The only difference I noticed was that the drive end on his crankshaft had provision for a woodruff key which locates an alternator rotor, whereas my T100 did not. His bike was also a dynamo engine. Like mine the drive end had a nut, lock washer, long spacer then the engine sprocket. So if Mr Miller wants to make his bike look more original with a dynamo and obviously a suitable regulator, he only needs to change the primary drive case and make or purchase a suitable spacer.

John Lines, member 9152

I must hold up my hand and admit to making a mistake. As usual, I read through the literature I have on Triumphs and failed to find a reference to the spacer! Plainly I need to learn more about Triumphs. FrankW I have located a wiring diagram which shows both alternator and magneto. In fact it couldn’t be simpler! The magneto provides the sparks for the engine and the alternator provides the charge for everything else; two completely separate parts of the wiring system. Makes complete sense when you see it and will present no problems at all when it comes to the wiring. However....

There is still a lot to do to get the engine running. The more I investigate the more ‘challenges’ I am uncovering. This could take some time. Been here before?

Malcolm Miller, member 3363