mitche

I added lights to my first TL (a '73; franken-bike was my name for it because it rose from two dead bikes) by first studying the existing magneto coil, trying to guess how many wraps it had, etc. That gave me some idea, after using the voltmeter, how many more windings would be likely to create about 13v. There was already an unused stator, so all that was needed was to wind it for headlight use. A trip to the electronics supply, and an hour or so winding the appropriate magnet wire around the unused stator gave me the power source I needed. A subsequent trip to the motorcycle scrapyard provided the donor lamp and bracketry. It actually worked OK without a voltage regulator, but after a number of months, the bulb did eventually burn out, so a voltage regulator would seem to be the wise route to take. Obviously had too much spare time back then while in school.

The in-line lamp switch (zip tied to the frame in photo 4803) is a nice touch of home. Looks like it may be running to the radiator fan, but it's hard to tell.

Those grips draw 36W according to the maker, which is probably a lot more than the factory headlight your bike comes with. I'd want to make sure the electrical system could handle that load before proceeding. Maybe you could rig up a 12v auto lamp of a similar wattage to test with first. I wouldn't think you'd be risking damage to the magneto/rectifier/regulator, but maybe someone else here can speak to that better than I. Going against most trials purists, I added the headlight from a homologation kit to my Sherco a while back. The lamp purportedly draws 15W, and have noticed that at or near idle, the light dims noticeably; not to mention the effect when the radiator fan kicks in. In other words, I bet you won't get much heat at idle, but if it's that cold, your radiator fan won't be competing for electrical attention as often.