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charging issue, bogging down...

  • Thread starter Thread starter midnightcafe
  • Start date Start date
M

midnightcafe

Guest
I have noticed my battery drains low quite slowly (two weeks or so of riding and the battery can't turn the starter motor) ever since rebuilding my '79 750L, but I put the blame on the high output air horn (139 dB!). Anyways, it's gotten worse, and now there's noticeable bogging off idle-I turn the throttle up to 4-5k and there's hesitation.

I put the battery on trickle charge overnight and got it up to 12.4V or so. However, when running, the voltage reads 12.4, 12.3 volts, and then DROPS when I twist the throttle. Any ideas where I should start looking? I'm busy as hell in school right now so I was hoping for some opinions from the GS board while I wait for the weekend to figure out the charging issue.

Thanks! -Emmet
 
Stator papers my friend are in you're future! When you measure voltage at the battery when the bike is running, it's not too surprising it might lose a bit just idling. But when you rev it up it should go UP to some 14V or so, if my memory serves. Sounds like a suspect Reg/Rect and-or shorted leg of your stator.

Not too bad of a fix. A few hundred for new parts. Getting the stator cover off is fun!
 
midnightcafe said:
I have noticed my battery drains low quite slowly (two weeks or so of riding and the battery can't turn the starter motor) ever since rebuilding my '79 750L, but I put the blame on the high output air horn (139 dB!). Anyways, it's gotten worse, and now there's noticeable bogging off idle-I turn the throttle up to 4-5k and there's hesitation.

I put the battery on trickle charge overnight and got it up to 12.4V or so. However, when running, the voltage reads 12.4, 12.3 volts, and then DROPS when I twist the throttle. Any ideas where I should start looking? I'm busy as hell in school right now so I was hoping for some opinions from the GS board while I wait for the weekend to figure out the charging issue.

Thanks! -Emmet
Click to expand...

Emmet,

Good that you have a volt meter.

Now look back on GSR home page, find the link for Garage,
http://www.thegsresources.com/gs_garage.htm

Look for the Stator Papers.
They are very detailed for checking lots of seemily small things that could cause chatging system to not be at its best.

Your situation seems like a problem of two things:
1) Total failure of something in the charging system, could be even failure of two thinghs. Maybe you can go straight to the stator open-circuit voltage test.
But you will want to check out all the other stuff too.
SOmetimes failure of stator will also cause the R/R to fail, and sometimes failure of R/R can cause the stator to fail.
(yes, this could get expensive)

2) And... maybe battery has a problem also. You say on charger over night and didnt charge up to much over 12 volts.
At least check the fluid level.

Tell us more what you find.

Dave

.
 
Last edited:
midnightcafe said:
I have noticed my battery drains low quite slowly (two weeks or so of riding and the battery can't turn the starter motor) ever since rebuilding my '79 750L, but I put the blame on the high output air horn (139 dB!). Anyways, it's gotten worse, and now there's noticeable bogging off idle-I turn the throttle up to 4-5k and there's hesitation.

I put the battery on trickle charge overnight and got it up to 12.4V or so. However, when running, the voltage reads 12.4, 12.3 volts, and then DROPS when I twist the throttle. Any ideas where I should start looking? I'm busy as hell in school right now so I was hoping for some opinions from the GS board while I wait for the weekend to figure out the charging issue.

Thanks! -Emmet
Click to expand...
You got charging problems as others said, but if all you get is 12.4 volt after an overnight trickle charge, your battery is probably history also. My old battery behaved same way- one weak cell left voltage at 12.4 after charging. The stator tests are best performed with a good battery, so now might be that time. I finally broke down and got an AGM battery from batterystuff in Oregon- $60 delivered and ready to go.
 
Not sure if anyone else has mentioned this, but you need to follow the Stator Papers. :-\\\

The only way your high-output horn can be blamed for keeping your battery discharged is if you are CONSTANTLY using it. :eek:

Even if you blast it for two seconds of EVERY minute, a proper charging system could keep up with the horn usage. :o

If you don't blast the horn, it won't affect your voltage at all.
noway.gif


.
 
HA! more issues

HA! more issues

So a fresh recharge has kept the bike in good shape, I've avoided running lights during the day (sort of illegal here :rolleyes:) and it's been handling loads great.

The positive battery terminal shook loose the other day which was fun (on/of power, wouldn't start half the time) but was a quick fix. Only problem now is that there is still bogging, only it's gotten very bad over the weekend. A new symptom is that cylinders 3 and 4 are cold :confused: I'll be flying to Kansas for an engineering competition and I'll take a look at this issue when I get back. I'm gonna check out the plugs, points, and might as well pull the carbs off and take a look inside. Any other suggestions, my ears are open. -Emmet
 
pulled the plugs and they're all carbon fouled, each with little to no spark after recharging the battery yet again. I'm gonna adjust the points then check the coils, but this is reinforcing in my mind that the R/R needs replacing.
 
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