Got voltage? I do...but it's weird... 86 VFR750

A new bike for me...going through restoring the beast from head to toe. Though she is SPOTLESS and only 7000miles, she's been sitting many, many, many moons. I put in a fresh battery and checked running voltage. 13.5 at idle...12.6 from about 2000rpm on up to 6K (I didn't rev her past that).. HUH? Since when did voltage drop when RPM's go up? Any ideas??

Mahalo from Hawaii,

thekelzer

 

Bad R/R or it's connector. Under left side cover.

 

+1 on the above

I guess its that time of the year when bikes come out of hibernation and the forum gets loads of reports of electrical problems - here is the drill - hope it helps you identify the problem and it is not too expensive to fix :

http://vfrworld.com/forums/5th-gener...-failures.html

The key thing to remember is all 4 components of the charging system (loom,stator,RR,battery) must be OK and a fault in any one can cause problems for some or all of the others. So even if you find a fried connector or wiring its still worth checking the whole charging system as it could have damaged the RR, stator...

Good luck let us know what you find.


SkiMad

 

Link isn't working...

I get good A/c voltage from stator.... and connectors all look ok. Still more volts at battery at low rpm than high.

Thanks,
KK

 

Would it make sense to anyone that the PO added a ground strap to one of the green wires coming out of the R/R connector? I disconnected it with no change in battery voltage...but what;'s the concept here. He did a VERY nice job splicing into the connector and then attaching the ground wire to the frame. But what's his concept here?

Thanks,

KK

 

Use the AC voltage scale of the meter, then connect one lead to any yellow (call it L1) and the other to another yellow (L2), then run the engine and measure how high the ac voltage goes at 5k rpm. Then disconnect one lead and connect to L3, and repeat. If you get 40 to 60 vac you're probably good on the alternator part of it.

The extra ground wire was likely added to make a lower resistance return path, probably some corrosion on the original wire or joint on the frame was causing a high resistance.

 

Yeah, like I say, everything checks out on paper, A/C voltage and diode wise....but still funky D/C voltages at the battery. I will re-attach the ground strap upon re-assembly.
Mahalo,
KK

 

Wow - How good is that! I just woke up and I see you already have the answer from the other side of the world

Basically with the RR disconnected, check to see AC volts between all three pairings of yellow wires. Hint take care with the multimeter probes - do not accidently cross connect any of the yellow wires/or connector pins and don't ground any yellow lead. If output on one or more legs of the stator wires is noticeably low then it indicates part of the stator wires have internally cross connected and will quickly lead to the death of battery and RR.

Re attach that extra earth.

 

Aggh trigger happy this time in the morning - hopefully this link will work..

http://vfrworld.com/forums/5th-gene...how-fix-common-regulator-stator-failures.html