Sorry,but this has nothing to do with my locost but I'm sure somebody will help me anyway. I've just bought a yz426 (motocross bike) that has an after market lighting kit fitted, problem is power is supplied direct from a stator and there is no regulation.So when you rev the nuts off it, it pops the headlight bulb.In simple terms how can I regulate the supply?
Cheers Colin.

hi

interesting - i had an experience like that 25 years back. I had a 1968 bsa bantam d14. On a ride once the gear lever fell off and was never to be seen again. Put it in second with mole grips and drove it home. High revs popped the headlamp bulb there too!!!!!!!


A solution might come from an old british bike too.

In electronics, there is a thing called a zener diode. It clamps at a specified voltage. However, they are not usually rated for the kinda loads on a bike. However, older brit bikes used to have a zener regulator mounted under the headlamp - its a strange looking thing with star shaped fins. These are to get rid of the head from regulation. There is a chance that they are 6v - if so you would need two in series.

Perhaps if you check in an old bike haynes manual - library? - or ask in a bike forum they might be able to tell you specifically what you need. Be aware a zener is polarity sensitive.

its usualt to use a resistor with a zener - but these may just go right across the power supply AFTER the ignition switch. Do a bit of research and dont take my word without seeing a circuit diagram or with the advice of someone who can verify.


atb


steve







[Edited on 17/11/02 by stephen_gusterson]

Theres a simpler fix, go the shoppe and buy the biggest highest wattage headlightbulb that will fit in the holder, and make sure you have a tail light bulb, all the clock bulbs fitted etc.
Ive got a old sp400 with no battery and magneto lights and if my clock bulbs blow the rest of the bulbs commit harikari when you hit peak revs.
Ive also got a 100W 12V haelogen headlight bulb in it and the stator was originally designed for 6v electrics!
It all seems to work once you get all the bulbs in as long with the exception that when I put the brakes on the rear light dims because it steals power out the circuits..
Its a balencing act, crap design, but robust!
Have fun :p

Just adding a note, I ran a voltage regulator (isnt there a lm712 or something all in one encapsulated thingy that does this) to my headlight on another bike, but it fubar'd its leccy ignition cdi, and we traced it back to the mag flux in the motor decided it'd take the cdi source coil route out the casing as it was a path of less resistance (reactance?) than the lights feed that was being regulated, thus overvoltaging the cdi ignitor.. Just a little thought

[Edited on 21/11/02 by MrFluffy]