Headlight dims and high beam indicator blinks... voltage regulator problem?

[Slomies]

I have a 93' katana 600 that I am trying to get ready for inspection but I am having voltage problems. I noticed my batter was fully drained (all the water even evaporated out of the battery) so I had it refiled, charged, and tested and it passed all the tests. The battery voltage was 12.9v when the bike isn't running. It however spikes up to 15.15v at ~5k rpms, which is causing my headlight to dim to almost nothing and causes my high beam indicator light to flash on and off. If I coast on the bike, the headlight goes back to working fine. I believe its my voltage regulator/rectifier that's starting to go, but I was curious if its a separate unit or if it is built into the alternator. If it is separate unit, can I get one from a gsxr and have it work? Any help or advice is appreciated. Thanks!

[Kreylyn]

I have a 93' katana 600 that I am trying to get ready for inspection but I am having voltage problems. I noticed my batter was fully drained (all the water even evaporated out of the battery) so I had it refiled, charged, and tested and it passed all the tests. The battery voltage was 12.9v when the bike isn't running. It however spikes up to 15.15v at ~5k rpms, which is causing my headlight to dim to almost nothing and causes my high beam indicator light to flash on and off. If I coast on the bike, the headlight goes back to working fine. I believe its my voltage regulator/rectifier that's starting to go, but I was curious if its a separate unit or if it is built into the alternator. If it is separate unit, can I get one from a gsxr and have it work? Any help or advice is appreciated. Thanks!

I'm not an electrical guy, so...

I'm sure there is a way to test the regulator. I don't know if you would be required to remove it first if you did.

It is located inside of the Alternator. You would need to open it up to get to the regulator.

A new regulator is probaby going to cost you at least $165 or so.

Krey

[kevin2502000]

14.4v is the ideal voltage, I'd say it running a little high.

[TheSteve]

Check your grounds. Lights should get brighter with voltage, not dimmer. Measure voltage between the headlights ground wire (black with a stripe I thought, I dont remember) and the battery's negative terminal. Should be zero. Anything more than zero means you have a grounding issue. On mine I ran an 8ga wire between the battery and the frame, and 10-12ga wires between high load components to the frame. No problems since.

The other thing to check is the alternator plug. Suzuki's plugs are severly lacking in quality and tend to like to melt. If its melted or corroded cut the plugs and solder the wires together. A high current device like an alternator doesn't like corroded plugs at all.

[Slomies]

Thanks everyone for your help and advice. I am going to test everything today (hopefully).

[Slomies]

I forgot to post up the fix to my problem... it was just my headlight bulb shorting the system! Luckily my car uses h4 bulbs so i was able to swap bulbs and test it out...

Everyone thanks for your advice....

[Nut-Nut]

I know you found a solution, but I had the same thing happen to me with my 92 1100... as it turns out, after changing the Rectifier and checking all the grounds the problem was the wrong bulbs in the front turn signal lamps. If you look at the wirting schematic, the same circuit that feeds the control voltage to the rectifier splits to power the dash and the front turn signal running lamps. If the wrong bulbs are installed, too small, then the rectifier recieves a higher voltage.. mine used to peak at 15.9 at 2000rpm or above... used to cook the batt after a half days ride.... I figured in case anyone else ran into a similar thing, i know this one drove me up a wall.... TonyE