Yamaha TRX850 Enthusiasts Forum

Hi all,
I have a charging problem in my trx.

Using the service manual I've gone through the checklist on pages 8-22 and 8-23 and found that
1) after going through the battery testing checklist, and battery is ok. Resting disconnected voltage is 12.9.
2) Turning the ignition on but before starting the engine the battery voltage is 12.8
3) With the engine running at 5000rpm the charging voltage is 12.8, therefore is no charging.
4) The next step is check the Stator resistance at the "A.C magneto coupler".

My problem is that I have no clue where this is. According to the manual on 8-23 the Stator coil has three white connectors.
There is a connector with three white wires going into and out of but I don't think that that is it. It's above the
Should I measure this through the connector or pull out the stator?

Any clues anyone?

It is the correct connector. It's located on the left side of the bike, under the bodywork, next to the fuses/solenoid/connectors for the sidestand switch and neutral switch.

tenner says regulator rectifier!

wanna buy one

if it is i would check the battery as they go fecked when regulator dies ,,,(regulator boils the battery)

But there is an inline fuse as well on mine to the live wire of the battery. If its the regulator they normally show different readings when connected and tested whilst the bike is running. Try running with all lights on as well to see if there is a drop in voltage, and then switch all ancilaries off to see how high it goes. If its running about 20 volts regulators knackered, turn off quick as it will wreck the battery.

Dave E

What was the original reason for suspecting there was a gharging problem ?

the way we test them at work is check the battery before you turn the ignition on. you want at least 12.6. start the bike and rev it to about 4000rpm you should be getting around 14.5 more then 15 and its over charging less then 13 and its not charging. do this with the lights on and off.

reg recs can show different readings if there breaking down. also abatery thats not holding its charge can as the bikes putting everything into the battery and the batery absorbs the charge making it seem lower then it is.

twolfes right why do you suspect theres a charging problem? duff battery?

I put in a new battery 3 and a half months ago. At that time the charging voltage was 1.4 volts above the charged battery. (just over 13.5 if I remember right )

Over the last few week I've had the symptoms of a weak charge. Stalling,
Now I have a flat battery, so I took it out and charged it.
The resting voltage of the battery (disconnected and left alone for a couple of hours) was 13.

I installed the battery again, connected up the cables and started the bike.
The voltage dropped to 12.8 and stayed there.
I revved it to 5000 and there was no change.
So I turned the bike off and checked the voltage again and it's 12.8. It looks like there is no charging voltage.

Kookiemonsta, are you talking about building lights? My headlights stay on whenever the ignition is on.

Randy sounds like you have an import, In which case put main beam on and also the 4 way flashers ( indicators ), and if someone could put the brake light on as well while testing, all to use up voltage, then to turn off everything you can.

Dave E

Nope. I'm in australia, the bike is australian delivery.

no in the uk you can turn the headlight on and off. if its on all the time no worries.

have you used the bike much since you brought the battery or has the bike been standing not doing anything?

also have you charged the battery since buying it on a charger? if so what charger? car? trickle?

When I bought the new battery I charged it on regular charger for 6 hours, which is what the charger instructions specified for MC batteries.

Since I put the new battery in I've ridden it 5 days a week, 60 kms per day.

deffo sounds like a rec rec problem.

Cheers guys!
I've ordered one, should arrive on monday.

Just to finish this one off, the part arrived a week late (oh well) I fitted it and everything is great..
Charging voltage is 13.7ish. That's from memory so it not be exact.

Though it's been to fcuking hot to take it for a ride, we had 38+ degree celcius days here in melb over the weekend. The forecast for next weekend is looking brilliant.