ty 250 lights

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tyandy
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Bike: yamaha ty 250b

ty 250 lights

Postby tyandy » Wed Aug 11, 2010 3:21 pm

hi ihave a ty 250 which i have just put lights on(The lighting was from the uk and it was for a xt500)The problem is that when i started the bike and reved it up,the out put voltage jumped from 6.5/18 volts.Is this a problem with the lighting coil(Shorted)or could it be some thing else????.Any help would great thanks..Andrew :D



David Lahey
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Re: ty 250 lights

Postby David Lahey » Wed Aug 11, 2010 5:03 pm

If there is no voltage regulator or battery/rectifier on your TY, the voltage will change with the revs.
You haven't said where you are measuring the voltage, if the lights are on or off when you measure it, or what voltage the light bulbs are.
The standard TY twinshock wiring had no voltage regulator or battery but if both head and taillight bulbs were connected, turned on and working, the voltage didn't usually go high enough to blow the (6V) bulbs.
I hope this helps


relax, nothing is under control

tyandy
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Posts: 3
Joined: Wed Aug 11, 2010 2:45 pm
Bike: yamaha ty 250b

Re: ty 250 lights

Postby tyandy » Wed Aug 11, 2010 6:48 pm

Yes it is a(b) model so there is no battery etc,yes all bulbs were in and when i started the bike they all worked.as i reved it up the bulbs all blew.Ithen tested the out put and everywere i tested it it had between 6/18 volts.at idle it had 1.5 volts.The way i understand magnetos the coil should be only capable of a max of 7.5 volts on a 6 volt system.thanks andrew



David Lahey
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Joined: Thu Jun 05, 2003 7:01 pm
Bike: Many Twinshocks
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Location: Gladstone, Queensland

Re: ty 250 lights

Postby David Lahey » Wed Aug 11, 2010 7:17 pm

If the circuit is open the voltage can go very high at high revs. Standard TY lighting with 6 V bulbs went from the filament glowing red at idle to bright white at about 4000RPM. Another 1970s jap bike I used to ride on the road (with the battery removed) made about 30V at high revs with the bulbs in use. I ran 24V bulbs in it for a while to avoid them blowing. I later ran a voltage regulator from a Husqvarna to keep the voltage down. That worked better because the lights then worked well down to about 1500RPM.
A common work-around to prevent blown bulbs on TY twinshocks used on the road was to use 12V bulbs.
From memory there is an intermediate tapping on the lighting coil so you should have a choice of voltages with the two wires. If you want I'll have a look in a manual to see which wire is meant to be running the lights.


relax, nothing is under control

tyandy
Junior participant
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Posts: 3
Joined: Wed Aug 11, 2010 2:45 pm
Bike: yamaha ty 250b

Re: ty 250 lights

Postby tyandy » Mon Aug 16, 2010 7:55 am

I have worked it out,After replacing all the bulbs with the right one it works :D :D :D .head light-6v 35w/35w..tail light 6v 5.3w/17w..hight beam indicator light 6v 15w.I love it when a plan comes together =D>




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