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Discussion Starter · #1 · (Edited)
My headlight dims at idle unless I have it idling at 1100+. I'm thinking the battery is failing. Either that, or Sherman and Mr. Peabody paid me a visit in the Wayback machine and I have a magneto....

Voltage:
Key off: 12.7
2000 RPM: 13.5 (max)
Idle: 12.5

Doesn't sound good
 

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Battery might be getting old but before you do that try replaceing the main 30 amp fuse,mine gave me a fit .it checked good but had a bad conection everything from the alt goes through it on its way to the battery.
 

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I would say everything is normal, including your tachometer which is not that accurate. Idle for my Bonnie is spec'ed at 1000 +/- 50 rpm. The tach is not accurate within 200 rpm, IMHO. I set my idle between 1100 and 1200 rpm by the tach and all is well. My first battery lasted well beyond 5 years.
 

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You know, my Bonnie and my ZX1100 both do that - in fact I am sure all the bikes I have had do it. Hmm. Mind is a bit fuzzy at the moment, but that's what I remember.

I'll check tomorrow.
 

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Those charging numbers look ok. Dimming lights like that is usually the voltage regulator in the alternator not a battery. That being said get your battery load tested and make sure. Since you battery acts like a buffer for your electrical system it potentially could be it.
 

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My headlight dims slightly at idle too. I'm not worried about it.
 

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Discussion Starter · #8 ·
Thanks for all the responses. I guess its safe to ride the bike. I was a little worried about getting stranded with my 9-year-old on board.

I did do some shopping, though. I discovered that the 14 series batteries (we have 12) have the same width and length, but are an inch shorter. Most have higher CCAs, too. I may get one and install it. I'll have room for a tool kit on top! I can use the battery strap to hold the kit and battery in place. I'll post some pics if I do it.
 

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Discussion Starter · #9 ·
OK, a little research has revealed the real problem. The stock rectifier/regulator is crap (surprise). Its a shunt-type affair that will never perform very well (say, like a car). Yamaha happens to put the best unit on the planet on some of their bikes (FJR, R1, even the Grizzly ATVs). It is the Shindengen FH012AA (MOSFET). They sell for over US$100 new, but they will deliver 14v at all RPMs. I just bought one off eBay for $50. It may take me awile, but I'll try to put together a DIY for anyone else thats interested. I will also relocate the unit. It will run much cooler than the stock unit, too.
 

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There is nothing like a guy answering his own question better than any of us can. :D Keep us posted on your progress, Joe.
 

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You know, my Bonnie and my ZX1100 both do that - in fact I am sure all the bikes I have had do it. Hmm. Mind is a bit fuzzy at the moment, but that's what I remember.

I'll check tomorrow.
FWIW........my Sportster does it as well.
 

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just noticed last night and tonight that my lights (all of them) have started flickering/dimming while the engine is running. they're solid when it isn't running. just found this thread and am keeping my fingers crossed that the 30w fuse got jostled and it isn't the regulator.

any diagnostic advice other than jiggling connections and such? i've got my multimeter handy, but not much background in electrics. just put a new tail light in, so maybe i didn't get it seated correctly? I'll check tomorrow. took the seat off tonight and tried moving the wires around with no effect.

tx!
 

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i may have gotten lucky. following the diagnostics instructions on the R/R page (http://www.triumphrat.net/maintenan...print/104504-rectifier-regulator-upgrade.html), my battery checked out for all the tests (as well as i could tell on my cheepo multimeter). but i did notice that the positive lead on my battery was quite loose. tightened it up before testing it w/ the engine on. dash, headlight and all others seemed to be constant. did all of this cold, so fingers crossed that the result remains after running her to temp. looks like R/R's performance drops the warmer they get.

just noticed last night and tonight that my lights (all of them) have started flickering/dimming while the engine is running. they're solid when it isn't running. just found this thread and am keeping my fingers crossed that the 30w fuse got jostled and it isn't the regulator.

any diagnostic advice other than jiggling connections and such? i've got my multimeter handy, but not much background in electrics. just put a new tail light in, so maybe i didn't get it seated correctly? I'll check tomorrow. took the seat off tonight and tried moving the wires around with no effect.

tx!
 
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