Voltage regulator

[SPUNKNLAZY]

OK here's my problem. I have a 93 750 katana and recently my battery cooked itself. Voltage at my leads without the battery and bike running is around 15.3 to 15.6. I'm thinking the voltage regulator is bad. My only question is were is the regulator located. Is it in the alternator or bolt on and what side is it on so i don't tear of both sides to look for it. Any help from someone would be greatly appreciated. And as usual thanks in advance everyone here has always been a lot of help.

[Kreylyn]

The regulator is a component of the alternator. To replace/fix, your most likely looking at replacing the whole unit.

Krey

[Wild-Bill]

First of all, you don't want to run the bike without a battery. That'll fry the regulator.

If you're getting 15-16 volts out of the alternator then it's fine. Check it again with a fully charged battery installed. The test procedure in the Haynes manual says that anything over 13.5 volts means the alternator/regulator is fine. If you were somehow getting huge voltage I'd wonder what's up but 15 volts isn't alarming, especially since there was no continuity through a battery.

[Kreylyn]

First of all, you don't want to run the bike without a battery. That'll fry the regulator.

If you're getting 15-16 volts out of the alternator then it's fine. Check it again with a fully charged battery installed. The test procedure in the Haynes manual says that anything over 13.5 volts means the alternator/regulator is fine. If you were somehow getting huge voltage I'd wonder what's up but 15 volts isn't alarming, especially since there was no continuity through a battery.

My manual says anything over 14.5v on the test = bad regulator and will fry the electrical.

krey

[Wild-Bill]

Which manual are you looking at? The Haynes doesn't list a max voltage and neither does the 1100 FSM.

Of course, all bets are off until a good battery is installed. The voltage reading should definitely be lower once there's less than infinite resistance across the terminals.

[Kreylyn]

Which manual are you looking at? The Haynes doesn't list a max voltage and neither does the 1100 FSM.

Of course, all bets are off until a good battery is installed. The voltage reading should definitely be lower once there's less than infinite resistance across the terminals.

If I have time tonight, I'll try to get a better scan/specifics on the testing in the manual I have, but...

Here is one prior KR discussion with pics of the manual talking about the regulator cutting out at 14.5v.

http://katriders.com/vb/showthread.php?t=55745

Krey

[Wild-Bill]

I guess you'd have to ask md86 where that came from but notice that the test is done with a load across the terminals. A battery provides that load. Testing voltage from a regulator without the battery hooked up tells you nothing and may fry your regulator.

[Kreylyn]

I guess you'd have to ask md86 where that came from but notice that the test is done with a load across the terminals. A battery provides that load. Testing voltage from a regulator without the battery hooked up tells you nothing and may fry your regulator.

Yes, 100%. Battery needs to be installed and at minimal 12.3 v to do any testing.

krey

[SPUNKNLAZY]

Regulator

I only had the terminals off for about 5 minutes. Then hooked it back up to the battery then rode for another 10 minutes then parked it. So hopefully i didn't cause any more damage. So if i have to replace the regulator in the alternator. Where would that be located. Not really sure what side of the bike it is on and can i get to it easily to replace.

[Kreylyn]

I only had the terminals off for about 5 minutes. Then hooked it back up to the battery then rode for another 10 minutes then parked it. So hopefully i didn't cause any more damage. So if i have to replace the regulator in the alternator. Where would that be located. Not really sure what side of the bike it is on and can i get to it easily to replace.

The regulator is an interal component of the alternator... it's generally easier to swap the whole unit (alternator) out then to fix the regulator seperately.

Krey

[newmotorguy]

Voltage regulator/high voltage!

I am dealing with the same issue on my 92 kat 600, I have 15.3 volts at 5000 rpm from the 1997 alternator I just received from fleebay. This is about the same issue as I was having with the original alternator which was putting out 15.2 volts at 5000 rpm. Since the alternator, regulator & rectifier are all one unit I figured it would just be easier to change the entire unit with a different one. Afterall they can't all be bad ...... right?
Well, I have a feeling that as these units are getting long in the tooth and have probably had god knows what kind of chargers, batteries connected to them, the regulators are failing. I am going to get a Ricks regulator and try that. Removal of the alternator is a pain! Remove the bodywork, tank, airbox and left sprocket cover and then you can get the alternator out of the bike, royal pain! I have checked all of my wiring, connectors, terminals, etc. and it all checks out good. Really my bike looks almost new and so do all of the connections, not much corrosion here in the High Desert. All of this started with a totally dry battery and it hadn't been that long since I had serviced it. So I looked at the Factory Manual and it said voltage over 13.5 volts was good, not giving a max voltage. So I figured it was good although from my automotive experiance that seemed too high. So I ordered a Shorai Bat for my bike and in the instructions it says anything over 14.7 voids the warantee. Back to the manual and in the section for testing the regulator it has a max voltage value of 14.5 volts. So I will try a new regulator and let you all know the results, probably next weekend if I get the part in time. Now it's Margareta Time!

[SPUNKNLAZY]

Thanks for explaining how to get the alternator out. I hope that's all i need shouldn't be that bad just a winter project.

[Marty78]

I just had issues with my electrics, pulled the alt/gen, replaced the rectifer and the regulator (which is actually very easy) but the bike still ran at 14.5v idle to 15.5v at 5k rpm. The rebuild shop says for that bike it is normal and you don't run into problems until 16v. Has anyone else heard this or tested their alt/gen and found this to be normal? Other than that bike runs fine.

[05RedKat600]

15+ volts will kill your battery. I don't know what else to tell you. I did go through three alternators for my Civic once. First one blew, charged at 17 volts, replaced. Second one surged between 13-16 volts. Third one charged at 15.5 volts. Finally the last one was good at 14.5 volts.

Oh, and it cost me a battery too.

[Marty78]

yeah that is what everyone keeps sayin, but the alt/gen rebuild shop says that on that bike, 15.5v is the norm due to a strange design factor. if anyone has a kat can they test theirs and see what it says?