'96 FXDWG. Have noticed recently that my trickle charger (old) is taking a bit longer to recharge my battery (also old), so I followed the sticky above with the following results:

Battery DCV x terminals = 13.52
Bike on, DCV x terminals = 12.70
Bike @ idle DCV x terminals = 12.69
Rev. to 2500 RPM = 12.94 (low beam)
Rev. to 2500 RPM = 12.89 (high beam)
Bike off, high beam on = 12.65

ACV Bike running = 27.2 .................. ??????

My meter's low setting on ACV is 200 and that is what I tested it on. I have not proceeded beyond the test results above. The 27.2 ACV seem significant and that would indicate a bad voltage regulator according to the sticky. Am I correct with my testing procedures, and do these readings indeed indicate a regulator in need of replacement? Also, would the 27.2 ACV running reading drain the battery while in operation causing the trickle charger to work longer?

Sorry if this seems obvious and elementary, diagnosing electrical troubles is not my forte.

Thanks for the sticky and any help/advice appreciated.

 

20 volts roughly per 1000 rpm, ac. 27 seems low at first gkance

 

In addition to the Sticky in this section there are two in the Tech Electrical section. They give us essentially the same info, but worth reading. Your voltages all point at the regulator, but carry on with the other tests, which will probably confirm the initial diagnosis.

 

27 vac is low. 33-36 vac@2000 rpm is the norm. Obviously the stator is still good. I have seen weak magnets in the rotor though that would cause your problem but no one replaces just a rotor. According to your info, the Regulator seems ok...

 

How old is the battery?

 

Rode the bike for about 30 minutes and performed the same tests again as before.

Battery V x terminals went from 13.52 to 13.03
Bike on, V x term. = 12.70 to 12.69
Bike @ idle, V x term. = 12.69 to 12.67
Rev. to 2500 RPM = 12.94 to 12.80 (low beam)
Rev. to 2500 RPM = 12.89 to 12.79 (high beam)
Bike off, headlight on = 12.65 to 12.62

ACV Bike running = 27.2 to 27.2

Service mgr. at the dealership said they would test the battery and dx. the problem for free tomorrow if I wanted to bring it in. I'll see what they say and get back, can't beat free.

The battery is 8 - 10 years old, Dr. Hess. Yes, I've got my money's worth out of that one.

 

Clarify the AC volts... is that with the regulator disconnected and taking the measurements from the stator terminals at the block? If so, what RPM's is the engine at when you get the 27 volts?

My thinking is you had the meter on the battery terminals and switched from DC to AC and that's where you got the 27 volts AC? If so, your regulator diodes are no longer effectively converting AC current to DC current, so yes, the regulator is toast. If I made the wrong assumption, then disregard.

However, you need to check the stator AC Volts output at 1000 rpm, then at 2000, then again at 3000 and note the AC voltage at each of those rpm's. That is measured at the stator leads at the block where the voltage regulator would plug in.

Just trying to get all the details...YD

 

YD, your assumption is correct, ACV of 27.2 was taken across the battery at idle. Thanks for the info.

 

AC Volts of 27 across the battery? Regulator is toast.

 

Yes, and the AC voltage that is getting to the battery is not doing it any good, swap it ASAP. I really like my compu-fire series type regulator. It regulates in a different way than most of conventional shunt type regulators.

Both Cycle Electric and Compu-fire make a "series" type regulator. It basically lowers the load on the stator as the electrical load decreases. In turn, the stator runs cooler and lives a longer life. Here is a great right up (link below) on what both types of regulators do and how they work. It's a long thread but pages 1 thru 4 give all the information. Page 1 demonstrates how a shunt regulator works with real world amp and voltage readings, and page 4 demonstrates how the series regulator works with real world amp and voltage readings. It's worth the read. Prices for either one are better than buying a shunt style from the dealer.

http://xlforum.net/vbportal/forums/s....php?t=1648679

Good luck with whichever type you go with. FYI, when switching it out, make sure you get good connection at the block connector, that is a known trouble maker and if the connection is not clean and tight, it could give you other troubles. Also take the time to run the "charge" or hot wire all the way back to the circuit breaker terminal. Some guys cut it and splice, but, take the extra time to run the wire in the original location with no splices. YD