YES! Problem identified and soon to be solved. Tested with a healthier battery and the problem remained. Then i tried connecting wires directly from the battery to the respective outlets on the reg/rec. Bingo! 14.5v at idle, throttled down to 14.4 and stable at any higher revs lights on or off! Using the electrosport test there was decent contact between the reg/rec and battery, 0.8neg 1.4 pos, but clearly the 'correct' values are a bit optimistic. Maybe a good mod to run the charging wires direct to the battery with some heavy gauge wire, which is what Il do as soon as I have some free time! Once again, thanks for the help guys!

HEY!! news update!!!

regulator/rectifier 33£ + shipping! UK free shipping and very cheap worldwide shipping!! USA-6.5£, Portugal 6.5£ and I guess it's 6.5£ worldwide lol

VOLTAGE REGULATOR for YAMAHA XV 250 Viargo XT 600 NEW on eBay, also Yamaha, Motorcycle Parts, Motorcycle Parts Accessories, Vehicle Parts Accessories (end time 16-Jul-09 23:36:53 BST)

uhmm I'm a little skeptical about that mod you mention...

Remember that you're doing that voltage test without engine load...for that you'd have to be riding the bike!

It could possibly kill your battery by letting to much power to her overcharging....the reg/rectifier is designed to control that voltage.....

You could however, fit that cable you're talking about and adding some resistors that could keep the voltage on the exact amount that will let the battery be charged safely..

The safest way would be if you could weld a few cable terminals on those cables that will fit tightly onto the reg/rectifier contacts!

Use preferably some insulated cable terminals.. we don't want to have any sparks comming out from the rear of the bike besides from the exhaust :rofl:

Did you understand what I was trying to say? If not, just tell me and I'll explain it better...

Vando :innocent:

Im a little confused as to what you mean...? Let me re-explain in case you've misunderstood.
The reg/rec is connected to the alternator as usual but instead of the output of the rec/reg getting to the battery via the entire lighting system etc its a single line to the battery. The voltage is still regulated but the detection of the voltage via the regulator is more accurate due to lower voltage drop from the shorter wires without external load. Bike load when running doesnt change, thats all still connecte as normal. I've used the standard plug into the reg/rec, iv just added the positive feed to an inch of the original wire. If I've made a mistake pls let me know!

The logic sounds good to me. Glad to see that you did not need to shell out for a battery.
Now all that remains is to fit a proper gauge cable.

Battery didnt worry me, its a smaller nonstandard one(srx frame) so fairly cheap, its the R700 rec/reg i was sweating over! Even mcomp where over R800...

Hello, I hope you don't mind, but I think I've got a similar problem with charging. I went for a ride with the multimeter extended to the battery and taped to the tank-top. On a long, straight road I worked through the revs and found:
Tickover - 4000rpm - 14.5V (I think good)
4000rpm - 7000rpm - 10V (I think bad)

The voltage steped down suddenly, almost like a switch had been flipped between two modes.

Will replacing the regulator/rectifier solve all my worldly woes? Or is my problem more likely to be elsewhere? Would the one Bacardi23 mentions do the trick?

VT

Exactly the same happened to me - different numbers but same pattern. A new reg/rec cured it, so now I have about 12.8v at idle and about 13.5v at fast idle.

Many thanks. I'll get one ordered.

VT

lol :) if ya get it from my link post a comment there...just to see how many get ordered :P

Vando :innocent: