Re: no lights?
First question: Are you using the exact same lights as your friend? A lamp or lamps with a wattage higher than about 2.5 to 3 is as large a lamp as you will be able to run without effecting the engine's ignition system. Keep in mind that, that wattage is total, or the combined wattage of both head and tail light. If you're using lamps of a higher wattage than your friend then that is your problem. If your lamps are identical then there is a difference in your magneto windings. I have one engine that will run a 3 watt lamp and one that will not. Same engine, same seller but obviously something different in the magneto.
Just re read your post and you say that if you install a lamp it kills the engine. You might want to check to make sure the lamp is not defective and grounding the circuit. I've seen lamps that would do that but looked good. Check it with a good ohm meter, or try another lamp. Does it kill the engine with the lamp installed but not turned on?
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Last edited by 2door; 10-03-2009 at 10:37 PM.