Charging system

[Thompz]

My first post about a slow cranking starter was resolved by replacing a battery thanks to this forum suggestion to replace the battery first. My second post question is about the charging system on 1982 xs400sj. I replaced the 35w/50w sealed headlight with a headlight with a h4 bulb style, with a 50w/60w bulb. I have noticed when I check the charging voltage with a meter the voltage is 13.5-14.5 volts around 3000 rpms and when i rev to around 4000-5000 rpms the meter will not read any voltage. Is this cause by the voltage regulator stopping the system from overcharging?

 

[drewpy]

should be charging at those revs, the 3k was what Yamaha recommended.

the voltage regulator on these bikes regulates the electricity into the alternator, so it determines how much volts it can put out. there is some kind of switching going on and that's why the electro mechanical ones fail!

 

[Thompz]

You feel that the 0 volts reading at 4000-5000 rpm is a natural function of this older technology. My 1999 Vulcan reads 14.5 volts at all rpms.

 

[drewpy]

no i don't there should be chargings going on!

 

[Thompz]

Is there an alternate voltage regulator that can be purchased as stock in no longer available.

 

[Thompz]

I purchased a used voltage regulator from a salvage yard. After installing I checked the voltage and the same results when around 4000 rpm the meter registered 0 volts same as the old one. I grabbed another meter and the voltage registered 14.5 v with the different meter at 4000 rpm. You learn something everyday I have a spare voltage regulator now and defective volt meter.

 

[drewpy]

I purchased a used voltage regulator from a salvage yard. After installing I checked the voltage and the same results when around 4000 rpm the meter registered 0 volts same as the old one. I grabbed another meter and the voltage registered 14.5 v with the different meter at 4000 rpm. You learn something everyday I have a spare voltage regulator now and defective volt meter.

never mind mate

 

[Travis]

I had something similar happen. I was checking to make sure the charging system and voltage regulator was working on a bike I was working on. Well the meter was jumping all over from 10-17 volts. I figured I had a bad voltage regulator. Turns out it was just the cheap multimeter and the everything was fine on the bike.

 

[OliverB]

A little off topic but still related: I would consider replacing the filament tail/stop bulbs with LED bulbs. While the addition of the 55/60w H4 bulb will work, it does tax our limited charging system. I have installed two LED tail/stop bulbs in my '80 400XS as well as in a couple scooters with minimal charging systems with excellent results. I did the math first and what you end up with is a brighter headlight using more amps but two LED rear bulbs which use almost no amps compared to the filament type bulbs so no additional stress on the charging system. Another plus is that when you apply the brakes the headlight does not dim.