91 electrical problems

I've been lurking on the board for a while, joined this morning.

I've been wanting a vfr for essentially all of my adult life, but kids jobs wife etc...you know the drill....
anyway, bought one last week. Rode it about 200 miles when it lost all electrical power. Traced to the main 30 amp fuse near the battery that had blown. I work on cleaning carbs (bike sat a year), changing plugs, etc for the next week. Go for a long ride saturday and all's great.

Now, yesterday the dash lights were dimmer than normal. Then the same...all power lost. The fuse didn't blow. The bike will roll start but won't stay running for more than a couple of minutes. I'm wondering, is this the regulater/rectifier problem I've read of? What's the series of plugs just forward of the battery? Anything you guys can do to help will be greatly appreciated, because after not owning a bike for 15 years, I'm really geeked to ride it.....but I'm not so damned geeked to push it home! :biggrin:

 

thanks....I'll search.

 

ok, so I took the R/R off and looked at it. It looks ok, no obvious signs of overheating, the plugs are clean, the wires going into it are also clean. I'm gonna look at the stator this evening.

 

The r/r usually won't have any signs of failure on the outside. To test it, take a digital voltmeter, put it on 20V DC. Make sure the battery has a full charge, at least 12.8 volts. Then start the bike, put the red lead on the + terminal and the black on the - terminal. Then read the voltage, it should be about 13.5. Then increase the rpm's to 5000. The voltage should increase to 14.5 or better. If the voltage increases then drops off before 5000 rpm, the voltage does not increase at all, or it does not reach 14.5, then the r/r is most likely faulty and shold be replaced. I got one for my 93 at rick's motorsport electrics for $120.

 

thanks vinny....I'll do it tonight.

 

The only thing I saw in the WIKI was for the electrosport vs OEM units. I did a how to on replacing the r/r, but no diagnostics. Maybe we should do a how to on that and maybe make a sticky in the mechanics section for diagnosing? What do you think?

 

vman and reg!

Hey guys I recently picked up a really good How to book on Motorcycle electrics. The advice given in the book was test the stator and test the battery. If those two check out then your RR is probably the culprit. Apparently the test for RR's are very unreliable, since one they can be hit and miss, and two they are hard to get proper readings from. So maybe a how to on stators and batteries?

Just a thought.

Oh, and Tmoeller that is the sexiest avatar ever!

BZ

 

my hagatar is famous on the bmw boards, on which I used to be a regular fixture on the off-topic board...

ok, so I took a voltometer reading...just battery, bike turned off was about 13.04 v. At idle 12.45 volts.....at 5500 rpm 12.45 volts....pretty definitive that it's the r/r at this point? Or should I still take it apart and look at the stator to be sure??

 

Yes, your r/r is toast. The stator cna be tested by disconnecting it at the 3 prong connector behind the right mid cowl (check your bike for the correct location, but for 90 - 93 it should be behind the right mid cowl), Place a + lead on one of the wires, and I think the neg lead to ground (I forget) bike will start and run with this disconnected as long as the battery has juice. Oh, important, set the volt meter to volts AC. rev the motor to 5K or so. The volts should increase to a max of about 75. If the voltage fall off, then the stator is probably bad.

In your case, moeller, I'd go with the r/r first. A stator from ricks is not expensive either. I put both in my 93 and never had an issue. Oh, the rick's r/r may be a larger than the OEM one. I ended up relocating mine to behind the subframe, in the wheel well area for better airflow.

Go here for a how-to on replacing the r/r: http://vfrworld.com/forums/maintenance/7271-r-r-replacement.html

 

thanks Vinny. I looked at the how-to, but I already had the r/r off so I'm good. I may use your advice and check the stator tomorrow before I order the r/r. I appreciate your help....I love having a bike, but haven't had one in 15 years so someone who knows what I don't is really helpful. I'm just looking forward to going outside any time I feel like it and starting it up and riding without worrying I'm gonna go dead 20 miles from nowhere.


I'll post the results of the stator test tomorrow. Thanks again

 

I'm with Vman that yourr RR is bad too. I had the same issues back in June and a new RR fixed me up. However, I have had some additional issues and they are stator related, so definately check the stator how vinney said!

BZ

 

One other piece of quipment you might want to add is a charging meter. Kuryakyn (sp) make one with LED's, it's inexpensive, easy to install, and you can tell if you battery is charging at a glance. You can find them online many places, I think bikebandit.com and riderwarehouse.com are acouple of places to find them. I put one on an 86 Radian I had and on my 93. When I thought I had my 93 fixed, this saved me from being stranded somewhere as it alerted me to the fact that I did not have the problem completly fixed, which resulted in my getting the new r/r, instead of just patching up burnt wiring.