so i have a '12 SG which i hear is notorious for bad voltage regulators. my gauge started bouncing steadily the last time i rode from 13 to 15. sometimes when i stop it quits but sometimes not. and it only does it after i ridden for a bit. anyone have this problem? how can i check to see if it is the voltage regulator or maybe a bad gauge?

 

Check you battery cables, positive cable at the starter and ground connections first. Make sure all are tight and clean.

Get a volt meter and hook it to your battery, start the bike and run it up to 2,000 rpm. The voltage should read somewhere between 13.5 and 14.7 and be fairly steady. If you see voltage readings of 15 and above or if it's bouncing all over I would suspect your VR is heading south.
You can also pull the stator connector at the VR and test the stator.
Check continuity, each pin to ground and they should all show open. Check continuity pin to pin to see if any are open, you should read 0.1 to 0.3 ohms. Last fire the bike up run at 2,000 rpm and check the stator output. You should have 30 - 45 V AC reading pin to pin.
Good Luck

 

I had a similar issue with my oil-pressure gauge. It turned out to be a short in the wire going to the guage (insulation had worn through where the wire went over my amp mount).

 

thanks i'll be doing that this weekend

 

the voltmeter in teh dash is notoriously inaccurate- it is also subject to voltage drop (like the voltmeter dips when you honk the horn, or wiggly wags with the turn signal).

confirm any readings with a voltmeter at the battery, if you have a tender you can use the pigtail to probe the battery- saves taking the seat off.

not an uncommon sight to see me riding around with a voltmeter taped to my bars...sometimes checking a charging system on one of my bikes or tuning with an o2 sensor rammed into the exhaust

with a real voltmeter you should never see readings above 14.8 volts, that would mean the regulator ain;t regulatin'



Mike

 

Mike,

Your explanation was on the money and with good clarity. How does this work?

 

o2 sensors generate voltage.

.5 volts dc is perfect

fewer is lean, richer is more...to a max of maybe .9 volts.

an o2 sensor needs to be in the exhaust where the gasses run past ( and through it) and will be heated to better than 600ºF

I use o2 sensors in my old Cadillacs, panheads, even my honda trail 90 to check the mixture under real conditions.
This helps me dial in the carbs

On some of the exhaust systems I had bungs wended in, on others I have the sensor on the end of a copper tube...I can ram it up far enough.

I attach the wires to my meter and tape it to the bars-

mike

 

I just went thru the bouncing gauge yesterday. Did all the tests on the stator and regulator, everything checked good, so I figured it had to be a bad connection somewhere. I traced it down to a corroded wire on the output side of the regulator right where it plugs into the regulator. cleaned all connections, put dielectric grease all around. now I have better voltage than I have had in a long time.

 

======================

LOL!!!

You beat me to it!

People often overlook checking the connectors on v-reg to ensure they are clean of corrosion & tight when people are having any type charging issues.

I did that as a maint chk over winter and also used some dialetric grease & a cable tie on each v-reg connector to ensure they both stay free of mositure/corrosion and tight too.

At the same time i also cleaned connections on battery and grnd and then used some bl locktite on connections to ensure they stay tight too.

Did same to the connector on throttle body thats notorious for getting dirty /corroded and or fretting (wear of metal terminals due to vibration) then causing motor to go into LIMP MODE & idling with little to no throttle response leaving people that arren't aware stranded on the side of the road.

scott

 

i loctite my battery terminals every time since i saw a guys battery melt down when his were coming loose. i'll be checking everything tomorrow. havent heard the o2 sensor check. i might try that too just to try it