[ted clement]

Buddy of mine rides a 400 that keeps blowing headlight bulbs. Dealer has replace about 5 so far, and diddled about with no real idea of what may be causing the problem, and he's reluctant to let them have it as it spends more time sitting and being worked on.

When three of us 400 Burgers ride togather and he is behind, his headlight is much, much brighter than the other two scooters. He has installed a voltmeter that reads pretty constant at 14.2-14.4 volts with a rare spike to 14.5. Reads the same on my 400, but I never noticed the spike. He says thats within specs according to the service manual.

Any suggestions of what to check for would be appreciated.

 

[NormanB]

Ted

Electrickery has never been my forte. Afraid - I am of the school 'if you cannot see it dont exist' type engineer.

However, I doubt a DVM is going to get to the bottom of this and I believe a generator spike is getting through I would recommend an additional earth line be fitted to the headlight assembly AND a new voltage regulator fitted (under warranty). Just thought it may be worth checking both generator and VR earths too.

If the dealer cannot cope with that then the dealer will have to fund it sitting there running with the headlight on and a scope to monitor (scope will need recording /memory facilty).

My mechanical reasoning for above is the current drawn by the headlight (once a stable temp is achieved) is effectively constant given a steady supply voltage and therefore it must be a voltage spike that is pushing in more current than that lil' ol bulb can wrestle with.

Of course I could be wrong - I often need help myself with electrickery probs. :wink:

 

[Randy]

I agree with NormanB check your voltage regulator -it may be putting out fine at an ideal but not cutting back as the engine revs.
Can your friend check the voltage while running at say 50 or 60 ?

 

[mactd83]

if the voltage regulator was bad you would be blowing more than headlight bulbs....computer would blow...all other lights... ignition...ect.
possibilities: make sure when bulbs are being installed human skin is not touching the glass part of the bulb, make sure bulbs are proper wattage also so you dont blow the fuses or burn up the wiring,if there was a voltage problem it would have to be in the headlight circuit only...just putting a meter across the battery wont tell you that...you have to set the meter up across the headlight circuit only. could be a possible pinched wire causing a slight intermintent short....or a bad ground as norman said the best way to check for a short is with the bulbs out make sure that from the positive side of the circuit to ground is open or you can put the meter in series to check for an amperage draw.

 

[NormanB]

if the voltage regulator was bad you would be blowing more than headlight bulbs....computer would blow...all other lights... ignition...ect.
possibilities: make sure when bulbs are being installed human skin is not touching the glass part of the bulb, make sure bulbs are proper wattage also so you dont blow the fuses or burn up the wiring,if there was a voltage problem it would have to be in the headlight circuit only...just putting a meter across the battery wont tell you that...you have to set the meter up across the headlight circuit only. could be a possible pinched wire causing a slight intermintent short....or a bad ground as norman said the best way to check for a short is with the bulbs out make sure that from the positive side of the circuit to ground is open or you can put the meter in series to check for an amperage draw.

As I prefaced electrickery ain't no friend of mine..............

However, and without knowledge of these new fangled computers on these new fangled Burgers - I would have though there would be a seperate voltage stabilisation circuit for this panel which may well run lower than 12 volts. As to the rest you could well be right.

:wink: :lol:

 

[ted clement]

Randy, it is being run with an aftermarket digital voltage reg that plugs into the cig lighter. Thats how we were able to test it on my scoot as well. It may be as little as 13.9 at dead idle, but immediately jumps to 14.3-14.4 at running speeds and holds steady there. Both scoots displayed the same figures, other than he said his would, on occasion, spike to 14.5. Maybe mine did too and I didn't catch it.

Will pass on to him the ideas presented. They certainly sound worth checking. One dealer simply offered to get him a new regulator, but neither of us think that is the problem. I like the idea of the ground or bad wire.

Wonder why Suzuki felt the need for a regulator to put out such high voltage anyway? The one on my 4 cyl, 4 stroke, ultralight motor puts out just a little over 13 max. Also arn't cars about the same?

 

[seatec]

Most alternators put out 14.7 v I think, Ted what kind of ultralite do you have and what motor, I had several with rotax motors in them few years ago. wayne

 

[NormanB]

snip
Wonder why Suzuki felt the need for a regulator to put out such high voltage anyway? The one on my 4 cyl, 4 stroke, ultralight motor puts out just a little over 13 max. Also arn't cars about the same?

Ted are you getting 'muxed ip' here - I think the generator/alternator can chuck out way more (like 17-18 volts)and the VR tunes it down to a max of around 14.7 which I believe is required to fully charge a 12 volt battery.

Then again I could be wrong. :wink:

 

[ted clement]

Seatec, NormanB.....I have an Xair 2 seater with a Jabiru 80hp on it.

The regulator/rectifier allows up to 14 volts max, mostly lower than that. Theres been instances of the original regulators, made by Kubota, spiking higher and blowing high dollar radios and such. Some of us changed these out for something we felt more reliable.

Just got off the phone with a local elec guru and he recounted an instance of similar blowing of bulbs caused simply by a poor connection of a wire between the generator and regulator...it this case it only required recrimping and that solved the problem.

 

[NormanB]

snip

Just got off the phone with a local elec guru and he recounted an instance of similar blowing of bulbs caused simply by a poor connection of a wire between the generator and regulator...it this case it only required recrimping and that solved the problem.

Hi Ted

Sounds good to me!

Please let me know the outcome ( and I like happy endings!! :wink: ).

Regards

NormanB