Does anyone know what Voltage should be  to front light from the XT250 Generator 
Thanks

 

Also Interested to know answer.

I might be being simple here  , but 12v if a 12v system, and 6v if a 6v system.

I'll try not to be simple but is iust an early XT like 1980 model in which case "i think" they were magneto driven lights so 6 volt. I'm also guessing a bit that it'll have a single wire AC regulator which probably stops it at about 7+ volts at about 2000rpm upwards. So regardless of if any bulbs are fitted or not, the Regulator should hold it steady with lots of voltage in reserve as bulbs are bought into play like indicators & stoplight etc which are dc & hard on the reasonably small battery but the alternator mag has to try to counter all those draws to keep the battery up. Did ya like that!! haha. I'm not gonna proof read it right now. Read at your peril.

Many thanks for that answer , reason i ask is having to rewire as previous owner took to cutting everything !!! so i have put a new loom from Rexspeedshop & had stator wires redone also. Bike starts fine the issue is the electrics but i have managed to get everything working but i am concerned how bright the headlight bulb gets & i do not want to fry my new loom considering its a 6 volt sysyem or does the voltage not apply due to generator driven headlight. Also i could not figure out what the blue-red wire & also the brown from the Left hand switch were for as the plug from the new loom do not account for them. & last question is the lights on & off switch only turns off the headlight not the tail light or instrument lights , is this correct ? . Many thanks in advance .

Blue/red is normally for the headlight park bulb, quite possibly UK/Euro only. However, the wire from the bulb usually plugs into one from the ignition switch (becomes live when switch in last position), not the loom.

Yamaha brown wire is normally switched live. Is it a gingery shade of brown, or more dark chocolate? Dark brown, dark green and brown/white wires from the left switchgear are for the indicators and the dark brown and dark green plug into correspondingly coloured triple females from the main loom.

Your bike should have a voltage regulator, so see if you can find this. It may well just have a single yellow or yellow/white wire coming from it, although my 12v RD125DX is a single green!

How many positions does your ignition switch have, including off?

Edit - blue/red is live whenever lights are on, and live by itself when ignition switch is in the last position. 

Switchgear has 13 wires 2 blocks and some single wires , black, dark green , yellow are headlight & are single wires , one block plugs into ignition the other block is brown ( not dark) , yellow , yellow & white , blue& red & a white wire , yes you are correct the regulator has a single yellow& white wire , the ignition has on /off , lock , park & the parking function i have working on the rear light

Thanks.

Could you post photos of the switches, wires and connectors? For this, you'll need a third party host, such as Imgur.

Did the switchgear come fitted to the bike, or is it a repro purchased afterwards?

i.imgur.com/XF5TptZ.jpeg

i.imgur.com/Y2DeADH.jpeg