I need help bad. headlight keeps blowing out.

vintageyamie

vintageyamie

Active Member
I'm building a 1975 cb500t and the headlight keeps blowing out when I rev it up. 4 headlight in a row now. I have good grounds to yhe headlight but it keeps failing as soon as I change it. Please help
 

Attachments

  • IMG_20130721_154257.jpg
    IMG_20130721_154257.jpg
    125.8 KB · Views: 216
Yep, stop changing the bulbs, get a meter and hook it to the headlight wires and rev the motor, read the voltage if it is going over 14.5V or so the regulator is caput.
 
Thanks i been reading into that but i wasnt for sure on it. Can i use any regulator/rectifier off any other bikes? I work next to a vintage motorcycle salvage and they have alot of cb450s out there and thinking maybe i can use one of those.
 
I just checked your bike on Bikebandit and it has a seperate regulator so you need to find one of those the part number for a 74 CB450 is exactly the same though so you should be able to use one of those.
 
Thanks for your time bub. Im going to go look at lunch today and see if i can find a good one out there. Ill hook it up tonight and go buy another bulb and see if thats the gremlin in my bike. Thanks again and ill keep you updated. If anyone else has any sugguestions im going to try the regulator first and then on to the next thing if that doesnt fix it
 
Don't put a bulb in it until you use a multi meter to check the voltage, no need on wasting another bulb
 
I dunno... can you? ;D

Get a multimeter and read the voltage across the battery terminals (while the bike is running). After it warms up, give it some throttle and hold it at 6000 RPM. Voltage shouldn't go above 15V and hopefully won't go above 14.2V.
 
vintageyamie said:
running no battery
Click to expand...

Do yo uhave a capacitor? if so, put the terminals on the + and - posts and look for same numbers or put the + and - on the leads from the headlight and see if it is goin over 14.5V there, anywhere after the regulator should never read higher, if it does the regulator is not doing it's job.
 
The solenoid is for the starter motor. Has nothing to do with the battery.

How many "changes" have you made to the electrical system so far?
 
vintageyamie said:
Do you mean the battery silenoid? I have that still hooked up. The bike will not fire without that hooked up.
Click to expand...

What is a battery silenoid? Do you mean the starter solenoid?
 
sorry this is the first build ive done without a battery. Im trying to teach myself all these things as i go as i have no one to sit down and teach me these things.
 
One of the purposes of the battery is to smooth the current and voltage spikes coming from the alternative, without it you will blow bulbs when these spikes occur.
You need either a battery, or a capacitor (~15000uF) in its place in order to work correctly.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom