Headlight keeps blowing

yozzer74

Been Around the Block
Hi I've got a problem with my headlight low beam keeps blowing. It's powered from munit.any ideas why this is happening??
 
My m-unit also blew front and rear lamp the other day, was under the impression it would protect the circuits from voltage spikes..
 
datadavid said:
My m-unit also blew front and rear lamp the other day, was under the impression it would protect the circuits from voltage spikes..

It'll protect from too much current, but not too much voltage. You'll still want a decent regulator/rectifier installed on your bike.
 
Sonreir said:
It'll protect from too much current, but not too much voltage. You'll still want a decent regulator/rectifier installed on your bike.
Mine is a brand new NOS part, funny detail is when i ran the rec/reg with the voltage signal coming from the m-unit, regulator was overcharging so i guess it couldnt read the voltage coming from the m-unit aux outlet properly. Had to hook it up from the ignition switch so it was reading plus side voltage straight from the battery to work.
 
Interesting.

I guess there was a little too much resistance in the m-unit. Good catch and also a very good solution to the problem.
 
Sonreir said:
Interesting.

I guess there was a little too much resistance in the m-unit. Good catch and also a very good solution to the problem.

Thanks, not bad for an electrical imbecil like me!
Not sure how great a solution it was since it still seems to overcharge or produce voltage spikes. Next move is to remove an unnecessary bullet connector between plus feed from regulator to battery, it may cause too much resistance as well. Havent gotten as far as to measure things hot and cold yet. Last time i checked, rec/reg was performing flawessly across the rev range, now the lamps blew with the bike fully warmed up and held at 4-5k rpms for a few minutes.
 
I've checked volts at battery most I get is 14.3v so think that ok .what other reason could the bulb be blowing
 
Vibration is the next common culprit. After that, we start getting into the realm of things that would cause voltage fluctuations such as loose wiring and the such.
 
Ok I'll check things out like tiring a rubber washer under mounting bracket .I was thinking it may have been something to do with light coming on when I start it .something to do with m unit settings. What you think?? Cheers yozzer
 
yozzer74 said:
Ok I'll check things out like tiring a rubber washer under mounting bracket .I was thinking it may have been something to do with light coming on when I start it .something to do with m unit settings. What you think?? Cheers yozzer

M-unit cuts out the headlight when spinning the starter, so that should be normal.
 
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