Solid State Regulator $14.99

[cmantle1]

ah, so black wire needs to connect to the brown wire from the regulator? (through fuse)

thanks i appreciate the help.

[ShakerNorm]

Here's the wiring diagram I (eventually) made up to show the whole mod


Sorry I'm a year or two late, but I hope it helps someone.

[ShakerNorm]

Probably easier just to use nylon screws..... not to mention simpler - and simple is reliable. Simple is good!

[xsleo]

Norm, thats about how I did mine. I put the fuse before where the black wire hooks to the brown wire. The fuse feeds power to both the reg and brush.

[ShakerNorm]

When I put in the new wiring harness, that was one of the things I addressed. I knew I wanted to put in a new (blade-type) fuse block, so I made sure I had one that had enough spots so that I could have one for the alternator fuse. Much better, and much neater - and if it fries out - I don't have to squirm through that nasty old wiring harness to find that stupid in-line fuse holder!

[madmax]

I've just installed a VR125/R296 equivalent (actually a "Modern Mechanics" CH543) wired exactly as per above diagram, replaced the 3 screws with nylon and fitted the rectifier upgrade.

At tickover (1200 rpm) I'm getting 11.8 - 11.9V which rises to 13+ at 1500 and 14+ at 2000, all measured at the battery side of the main 20A fuse, is this about right? I was expecting more than 12v at tickover, am I being unrealistic or is this down to dirty contacts in the ignition & kill switches?

cheers

Max

PS, I can highly recommend Sonoran Desert Autoparts in Gilbert Arizona, the regulator cost me $17.00 inc delivery to the UK and it arrived in 11 days, great service.

[xsleo]

The battery voltages you are getting are good.
If you check the voltage at the black or brown wire at the brushes it should read at or very near battery voltage. Even .2 or .3 volts less means dirty connections.
Often in the key switch itself. They can be taken apart and cleaned. Bright and shiny is a good thing. A dab of Dialectric grease will keep them clean.
Leo

[madmax]

Thanks yet again Leo

I'll check things out again tomorrow and maybe fit some heat shrink to the black/brown where it connects to the brush just in case there's any leakage (short) to the adjacent connection.

cheers

Max

Edit

I checked things out today, with the engine off and the killswitch in the off position, I'm getting 0.4V less than battery voltage at the outer brush connection, as soon as I turn the killswitch to run the drop increases to 0.9V. With the engine ticking over, the difference is typically 0.4-0.5V

The brown wire at the ignition switch is showing battery voltage so the drop is somewhere between there and the brown at the 3 pin connector above the regulator (resistance between green at regulator and inner brush and brown wire at regulator and outer brush both 0.3ohms)

I've put the battery on charge overnight, it took some stick today chasing voltages and will recheck things tomorrow.

[xsleo]

Your drop may be right in the connector. Pull it apart, best to remove the wires and clean the metal ends, a bit of a squeeze on the female halves will tighten the connections. A good electrical contact cleaner in a spray can will do a good job.
Leo

[madmax]

I managed to get myself totally confused today.

I can get battery voltage at the green wire as long as it is disconnected from the reg, as soon as it's connected I drop of 0.5V at the outer brush, when I checked the earth from reg to battery negative I get 0.2 ohms with the ignition off, turning on the ignition introduces a resistance of 6.0 ohms which I assume is causing the voltage drop.

What is even more confusing is with the ignition off I get a typical resistance of 0.2 - 0.3 ohm between the batt neg and anywhere on the frame/engine, turn ignition on and this instantly goes up to 30+ ohms.

Charging must be significantly better than previous though because the headlamp doesn't dim when revs drop, similarly the neutral warning light which used to brighten when blipping the throttle.

Max

[xsleo]

The green wire goes into the reg and hooks to the transister and when the transister turns on, it grounds the green wire. Any voltage there happens when the transister is off.
This voltage is a moot point, don't mean anything.
Power flows from the battery to the brush, through the rotor, out the other brush. Then goes to the reg on the green wire. When the reg sences low voltage it turns the transiter on, this lets current flow through the rotor. This current magnatizes the rotor. Which excites the stator to make power to charge the battery.
As long as the reg and brush get battery voltage and the rotor and stator function, they put out power.
The system is simple, don't over complecate things by measuring things that don't matter.
On your ohm readings, alway check without power on the circuit. Once you add power then the readings are meaningless.
When you check battery voltage while running, is it about 12.5 at idle and go up to 14.5 at 2500 and above? Never going over 14.5 at any rpm? Then It's working. Ride, enjoy.
Leo

[madmax]

It's working, I'm riding & enjoying, thanks again Leo.

Max

[billspirit]

NAPA lists 2 diff kinds of #mpevr38sb. one says voltage regulator. the other voltage regulator transistorized. I assume I want transistorized correct ?? bill b

[xsleo]

Yes, I think even the one that doesn't say transistorized is. Just to be safe get the one that does say transistorized.
Leo