On the 20th of September I was riding home on I-15 in the dark.  The bike had run great on the 25-mile outbound trip, and had started up without complaint for the return trip.

About halfway home, on level ground, the bike suddenly started bucking.  I had gone less than 30 miles since filling up, so I was pretty sure it wasn't a fuel problem.  But whatever the problem was, it was obvious that I needed to get off the road.  The headlight was coming and going along with the engine, and I knew I was "near the end".  I was in the "fast" lane next to the HOV lane, so I had to cross three lanes (including an on ramp) to get to the emergency lane.   I couldn't tell if my taillight or turn signals were working, so it was kinda dicey in the dark.  Luckily, there were no cars in my immediate vicinity.

I had only gotten over one lane when the bike went POW! and died.  I pulled in the clutch and kept moving over a lane at a time with my head swiveling back and forth to make sure I wouldn't get run over.  I had been doing about 75, so I coasted for almost half a mile ... using the headlights from passing cars to illuminate my path.  I was going pretty slow when the next exit started coming up, so I stopped in order to stay safely out of the way of possible "early exit-ers".

The bike wouldn't start.  It wouldn't even "tick".  I knew the fuse was OK, because my oil light came on, but that was IT.  In other words, I had an electrical problem with some meat to it.

I had brought my TracFone along, so I figured I could call my wife and get some phone numbers for friends / neighbors / coworkers with a truck.  Only I knew I wouldn't be able to hear her, standing there on the side of the freeway.  So I started walking toward the exit with my helmet and tank bag.

I had only gone about 50 yards when a bike went past with a "Potato Potato Potato" sound.  It slowed and pulled over about 30 yards ahead of me.  When I caught up with it, the rider turned to me and said, "I hate it when that happens!"  He turned out to be a local Harley rider, in his early 60s I would guess, who had taken his Sportster out for a spin.  Was I glad to see him!

He gave me a ride to a Chevron station, where I borrowed a phone book and started making calls.  My coworkers (with trucks) who lived between there and home didn't answer, and neither did the first few neighbors I tried.  I finally reached a 70-year old neighbor, who came to rescue me with his pickup and his beefy grandson ... and a ramp and tie-downs from another neighbor.  (Thank goodness for the grandson!)

The whole "adventure" only lasted about an hour and a half.  It could have been a lot worse.  In fact, some of you may remember that I was planning a trip to the Grand Canyon.  I was supposed to have left the week before, but things heated up at work and I had to cancel.  Whew!  It would have been a LOT worse to break down in the middle of the Arizona desert....

I put the battery on the charger, and it was fully charged in the morning.  Hmmmm.  OK, so the battery had kept the bike running as long as it could, but it must not have been getting charged.  Prime suspects?  The alternator and/or the regulator/rectifier.

Within a day or two I was able to do some tests.  The charged battery started the bike ... no problem.   I tested the alternator, but the results were not exactly conclusive.  No shorts or breaks, but the alternator only put out ~62 volts AC compared to the 75V minimum listed in the Haynes manual.  Still, the voltage across the battery terminals was a (barely) acceptable 13.5 volts DC with the engine running at 5,000 RPM.

At this point, bad weather and/or getting home from work after dark got in the way of further testing ... until today.  I re-ran the alternator tests, with the same results.  Then I moved to the other side of the bike to test the regulator/rectifier.  Bingo!  Everywhere I should have found 6 ohms of resistance, I measured nearly 8K ohms.  And where I should have measured 40 ohms I found an open circuit (infinite resistance).

Where does all of this leave me?  Looking for a replacement R/R unit.      See my ["WANTED" thread].

Can anybody help?

Yeow, that's no fun.  Goes to show not all Harley guys are bad.   

So what caused the POW!?  Do you think it backfired when the power went out, or does the regulator have a big smoking hole in it?

If I had a spare I'd drop it in the mail today.

I had a look at the regulator-rectifier site.  They look new to me.  I would be inclined to call them and ask.  Alternatively, they may have a universal solution. 

Hope you get it back together shortly.

Something similar happened to a buddy of mine. Basically running on the battery until it ran out of juice, filled the carbs with gas and then had 1 more spark to ignite the fumes. I was behind him when it made an awesome fireball. The bike had been envolved in a couple of wrecks and later he found a short in the electrical system.

Quote from: dgyver on October 16, 2007, 05:31:42 AM
Something similar happened to a buddy of mine. Basically running on the battery until it ran out of juice, filled the carbs with gas and then had 1 more spark to ignite the fumes.

Yep - by the time I got to the Chevron station, this is exactly what I figured must have happened.

Quote from: GeeP on October 16, 2007, 05:02:53 AM
So what caused the POW!?  Do you think it backfired when the power went out, or does the regulator have a big smoking hole in it?

No hole.    I figure the reg/rect probably "popped" when I started the bike to come home, and the battery did its brave best for 12 miles.


Hmmmm ... if the alternator is only putting out 62 volts AC instead of 75+, the R/R must have been working overtime to supply a nominal DC voltage to the battery.  I wonder how long I can expect a replacement R/R to last under those circumstances?

I plan to write up the test procedures tonight (I've taken the photos already).  Maybe a couple folks could break out their meters and let me know what their readings are ... just to tell me if I'm in the ballpark?

I may have some measurements from previous repairs, they were at least 70v though. I can get readings from 2 of my bikes.
Doug (starwalt) took some static readings of several stators that I had. Maybe he still has them. We were trying to determine a way to check a stator that was not installed.

Thanks dgyver ... that would be great! 

If starwalt doesn't make an appearance, I'll try to contact him and ask about his "data store".

WOW... Sorry to hear about your mis-adventure 

I hope you can get back on the road soon 

Quote from: Kerry on October 16, 2007, 10:06:02 AM
Thanks dgyver ... that would be great! 

If starwalt doesn't make an appearance, I'll try to contact him and ask about his "data store".

You rang??

My readings were of the inductance of the stator using the "L" function of my mulitmeter. If you happen to have that function on a meter, then we can compare notes.

My idea is to make a circuit you connect the leads from the stator to and have it give a "Green Yellow Red" output indicating the range of inductance of the windings.

A dead short or open should be a "Red" condition.

I'm gonna check the posts on your reg/rect request. It seems to me that a fair trade for a Kodak is in order. 

I'd be happy to submit some readings, just let me know what/where you'd like to know what is going on.  I'll have a new battery in my '00 soon, and can get my DMM on the job for it.

I must be getting old.... 

I just found THIS OLD POST where I told someone that I had an extra regulator/rectifier.  I'm going to rummage through the shed tonight to see if I still have it.  If I do, and it tests out, it's going on the bike!

So don't send out those packages ... yet. 

Kerry, you sound like me.... having stuff but forget that you do.

any 5 wire voltage reg should work off of many suzukis and even yamadogs

i think i have a TL one for my bike

with some extra cooling fins

Quote from: dgyver on October 16, 2007, 06:03:59 PM
Kerry, you sound like me.... having stuff but forget that you do.

I don't have the extra R/R unit after all.  I looked everywhere I could see (or think of) and ... nothing.  Then I got the bright idea to look through my (manually) archived PM conversations with GStwin'ers.  Sure enough, I sent my extra R/R unit out on 16 April 2005 ... to the party-in-need from that old thread.

Oh well!  I guess that means I'm back in the market.

YAY for fellow riders and good neighbors!!   I hope someone has the extra R/R unit for ya'!

Quote from: pandy on October 17, 2007, 10:39:32 AM
YAY for fellow riders and good neighbors!!

I'll second that! 

Quote from: pandy on October 17, 2007, 10:39:32 AM
I hope someone has the extra R/R unit for ya'!

Here's where we add a "YAY" for fellow GStwinners.  starwalt is ending me an extra R/R unit, and several others made great offers.  Thanks, folks! 

YAY for GSTwin members, too!!!

starwalt is my hero. Hi starwalt!!!!! 

(Shameless temporary threadjack from a desperate women: vote here!!!) 

Quote from: Kerry on October 16, 2007, 08:56:53 AM
I plan to write up the test procedures tonight (I've taken the photos already).  Maybe a couple folks could break out their meters and let me know what their readings are ... just to tell me if I'm in the ballpark?

OK, so I'm one night late. 

I have a replacement regulator/rectifier on the way , but I would still appreciate some feedback on the alternator side of things.  For the testing procedure, see the new [HOW TO: Test the charging system] topic in the FAQ forum.

I was not sure if you still wanted the readings. I might get some free time this weekend, unless it rains tonight.

Quote from: dgyver on October 18, 2007, 03:58:33 AM
I was not sure if you still wanted the readings.

No problem!  I didn't want to ask for measurements until I supplied the "How To" ... for folks out there who don't have a manual yet.

I should have mentioned that the measurements I'm most interested in are the ones from step 19 in the "How To".

Thanks in advance to everyone who takes the time!  I really appreciate it.