Voltage regulator failing?

[mystahagy]

Hey all,

Well for the second time, either the high beam or the low beam has gone out on my sylvania silverstar after about 5 months use. Also when the electrolyte level is at the full mark, it'll bubble out the overflow tube when running at high rpms for extended periods of time, ruining the finish of course on my swingarm. Aaannnnddd, all lights will slightly dim at idle. I figure that's normal, but worth mentioning. Another strange symptom... the bike will run 10x better if it's sat for a few days versus a few hours. Hmmm....

Tomorrow I'm going to clamp my multimeter probes and see what kinda DC voltage it gives me while revvin' it up. But as far as what's too high or too low, I'm not certain.

Now, I looked all through my clymer manual and whadya know... it barely mentions the voltage regulator. Nothing on locating, testing, or replacing. Does anyone have any ideas or tips on this? I've already checked the muffler bearings and the blinker fluid, so I know it's not that. If this sucker is on it's way out does anyone know where one can be had on the cheap. I just want one that works, not a pretty new one. I'm tired of burning those 20 dollar bulbs out, but I'm sure this also has a negative impact on the whole system.

[md86]

The regulator/rectifier is INSIDE the alt assembly . K says that he replaces the entire unit instead of taking it apart to replace one part , which isn't really THAT hard (I did it a couple years ago) . I actually think I still have my OLD regulator (which apparently wasn't bad anyway) in my closet somewhere I could dig out . See what the multimeter says , then we'll talk . You can test the reg/rec , but I THINK the book says to take the parts out to test them , too .

[kiba]

You just need to check the voltage while it's running. It should be between 13.6 and 14.4 at 5000 RPM, and never go above 14.4 at any point. Everything being a little dimmer at idle is normal as the alt. is not putting out full power at those slow speeds.

/kiba

[ThAzKat]

14.5 is normal under throttle. anything less than 13.5 isn't putting enough juice through the system. To do a ohms test you will have to Isolate the Reg/Rec. from all connections. On the voltage check, if the reg/rec is bad it will read real high or real low. for instance, low would be 10 volts, on the high side will be 17-18 volts.

[mystahagy]

Well I pulled it outta the garage and ran it with a voltmeter on the battery. 15.5 volts at idle, and when revved up to around 5k it goes up to about 15.75 volts. From what ya'll are sayin that's too high, needs to be replaced right? BTW I got your pm md86, thanks.

[The CyberPoet]

Well I pulled it outta the garage and ran it with a voltmeter on the battery. 15.5 volts at idle, and when revved up to around 5k it goes up to about 15.75 volts. From what ya'll are sayin that's too high, needs to be replaced right? BTW I got your pm md86, thanks.

Yup. Way too high... Time to replace.
Oh, and the expected lifespan on Sylvania headlight bulbs is 100 to 150 hours of run time according to their info.

PS - test procedures for charging systems & batteries is here: http://www.motorcycleanchor.com/moto...lectrical.html

Cheers,
=-= The CyberPoet

[ThAzKat]

Yes it is way high, your reg is bad!

[md86]

Well , mine was charging SLIGHTLY high a couple years ago (like .2 volts above spec or something) and I changed my reg/rec assembly deal out ($100 @ Ronayers BTW) , and the was no change . SO that was the end of THAT as far as I was concerned . Still charges slightly high , but I never have problems with bulbs , and I just check my battery every once in a while to make sure it ain't dry (haven't added hardly any water to it this season) .