Electrical troubleshooting request

Electrical issues
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Posts: 87
Joined: Wed Jun 01, 2005 3:46 am
Location: Tokyo

Electrical troubleshooting request


Post by suicideshovel65 » Thu Apr 10, 2008 2:37 pm

Description: A shorting wire within the dash or within the headlight circuit

Post by suicideshovel65 on Oct 20, 2003, 5:30am

Okay - I'm sure that some of you had to have had bets going on how long before this request would come after my "first panhead ride" post! heh heh
rode the bike down to Hayama on the coast south of Tokyo on the weekend - nothing long, just about an hour and a half each way. Bike ran strong on the way down, and strong on the way back except for a few issues towards the end of the return leg.
We encountered heavy traffic on the "express"way at the end of the trip, which meant a period of running at lower speeds with the light on. The lighter grew dimmer and dimmer until it was just an unhealthy glow - not enough to light the road at all. The bike was running okay though.
Then as I left the expressway for the final short run home on city streets, the bike started running unevenly as though there was a fuel flow problem (ie like it gets when it's time to go to reserve). Gas was low-ish, so I topped up at the first gas stand 100 yards further on, restarted, and took off again. Again the stop-start behavior, but this time more obviously dying rather than starving, accompanied by backfires. This time I figured electrical. I switched off the light switch (still a very dim light) to cut the engine as I was coasting to the side of the road whilst it was dying and the bike surged into life again. I ended up riding home slowly on backstreets with the lights off.
Checked the charge on the battery when I got home, and the thing was fully charged.

My questions:

The cause for the stop/start behavior when light switch is on - perhaps a shorting wire within the dash or within the headlight circuit?
The cause for the light growing progressively dimmer?
I would have thought the bike was perhaps not recharging, but when I got home the battery was at full charge...

Any ideas?



BTW whilst it was running I was impressed with the drive it has - cruised fine at 55-60 (although friend riding with me said we were going 100-120kph, so here must be some inaccuracy with my speedo).

Post by kell on Oct 20, 2003, 3:35pm

Your symptoms are exactly, precisely what you get with a dying battery from a failure of the charging system (probably the regulator).
When you say the battery was "fully charged," what was the voltage? A fully charged battery should read 12.7 volts or so, more if it just came off a charger, sometimes 13. And it is only "fully charged" if it will put out a current, no matter what the voltage meter tells you! If it won't light the headlight, you can't say it's charged. Of course, a short that's draining off the power could cause that dimming, but I doubt it very much, from the way you described the bike's running. And why would it come to life when you turn off the light? Because the battery is dead and doesn't have enough power the run the light and the coils at the same time. I know about failed charging, been there and can save you from scratching your head any more.
There are things you can do by way of troubleshooting. One, connect a cheap Radio Shack voltmeter to the positive wire from the battery where it connects to the coil, ground the other lead, and lay the meter on top of the dash next time you ride. Two, disconnect the voltage regulator and try running direct off the generator, but don't rev up too much or you might burn out the headlight. Now watch the headlight and the meter. This is what will happen if your regulator failed (or the relay stuck): you will get electrical power, and plenty of it. You can even ride the bike for a while directly off the generator -- in the day, without the headlight -- if you don't mind overheating the battery. If running off the genny doesn't get you the power, then something's wrong with your generator.

Post by suicideshovel65 on Oct 20, 2003, 6:11pm

Hi Kell,

Thanks for the pointers. The bike would run with the light switched on, just very spasmodically. I figured this might be caused by a short, but as you say that doesn't explain the dimming light.
When I hooked the battery up to the charger the needle whacked the far limit of the charge indicator - ie it was definitely up around 12.x volts.
If I have removed the battery at any time (I replaced the old with a new when I got the bike), do I need to polarize the generator at this time? Would a failure to do this potentially affect the charging system or running of the bike?
I will try the tests you mention and perhaps look at another regulator (be good to have a spare anyway).
Thanks for the response, and keep us posted on the magnets!

Post by irnwkrz357 on Oct 20, 2003, 8:13pm

when mine did that i found that the metal ring around the end of the generator was shorting one of the brushes out....i just removed the ring and dont run one now....when reving i get about 14.5 volts.....

Post by kell on Oct 21, 2003, 4:01am

One piece of advice I gave you was off the mark. Connecting the battery directly to the generator isn't such a good idea.
Time for the dead horse beating. I'm not there but symptoms you describe match perfectly what happened to me when my voltage regulator failed and the bike stopped charging. Light dims, bike runs erratically; switch light off, bike starts to run again. Three times I just made it across the Williamsburg bridge at night and either puttered home without the headlight or had to push it, before I finally figured out what was wrong. The fact that I kept charging the battery again and again should have clued me in, but nooo. I even took out my electronic ignition and went back to points, mistakenly thinking there was something wrong with the ignition. Live and learn.

Post by Dereborn on Oct 21, 2003, 11:10am

Same symptoms when battery is dying. I once had exactly these symptoms, filled bat with dist water, charged, ran for a cpl of miles, and - same thing... over and over again...
Until i lfted the bat out and found a tiny hole in one of the cells...
Before this season I had my entire electrical system re-done, still 6V, and it's been working like a dream! Strong bright light, easy starting and no worries!
You definitely live and learn with these bikes!

Post by dirtydistrict on Oct 21, 2003, 4:57pm

If you use one of these f...... electro mechanical voltage regulators, put it on the ground, then give it a furious kick. One of these marvels get stuck and turned my generator to electric starter, not talking about troubles mentioned here, so I changed for a "cycle electric" reg and don't have the extreme pleasure to play golf with these black boxes anymore. ..
By the way, we had extremely hot temperature here in Europe and my battery went so empty that I could'nt believe it ! (it was all dry) I plan to do a serious battery insulation in my oil tank as OEM location is not the best place even under normal temperature

Post by mtnspan on Oct 21, 2003, 8:24pm

Sounds like a bad battery. I went to a sealed gell type. One thing I found is that the regulator has to be grounded where it mounts, also anytime you disconnect any part of your charging system you must repolarize the generator. To do this, take a piece of wire and just flash the terminals between the battery and the field. Don't hold it too long, just long enough to get a spark.
The contact points in my regulator will stick from time to time, a tap on its side usually does the trick.

Post by DuoDave on Oct 22, 2003, 11:35am

Well, I reckon my bike has two advantages here. I have a twelve volt alternator which runs it's current through a solid state regulator/rectifier, so no golf lessons for me, D.D.. Secondly, I have the police model square oil tank hanging out the right side. This means I can use just about any size battery and it doesn't get cooked from being surrounded by a hot oil tank.
I have no doubt that my electrical system will be afflicted by it's own set of gremlins in the future, and my oil tank doesn't look as pretty as the horseshoe type, so you pays your money and you takes your choice.

Post by suicideshovel65 on Oct 27, 2003, 2:34am

Hi everyone, after a few more issues over the weekend (yet another ride with the mates cancelled) it appears that the problem is indeed the generator/regulator not putting out charge.
I will take a closer look at the two this week and see what can be salvaged out of them. If they look shot I will order one of the cycle electric combo units and overhaul the old generator for later use/spare/etc.



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