On my 3rd Electrex RR51 in 3 years !
Have used most of the tips posted here, thermal paste, new wiring, even fitted an aditional heat sink, but still failure of RR.
Have good earths etc.
Was thinking of the additional Earth wire ?
Has anyone fitted a small PC cooling fan on top of the RR ?
I think it has been mentioned in another post that the RR creates a lot of heat, especially if the battery is full.
Does anyone know where a fan could be connected to ?

Maybe I'll just continue to fry eggs on it

Cheers

Bomber

Hey man, I got your back!
I installed a small fan (12v like the kind used on a computer CPU) a couple of years ago. It comes on when I turn on the switch. I'll make some pictures and post them for you. Also, a major problem is the connections at the steering head in the wiring harness. The connector plugs from the voltage regulator into the wiring harness can get real hot. Check them next time while the engine is running (be careful) and see if they are to hot to touch. If so, there is corrosion somewhere (maybe at the very same connectors) or they may even be melted. I replaced mine about 3 years ago after they melted so bad. I used some connectors from a trailer hitch wiring harness ( only thing I could find that was big enough) and soldered them in and so far so good. Maybe you should change brand of regulator this time, maybe try the electrosport. Again, I'll make some pictures and post them for you.
du907

Ok, here are some pictures. On my bike ground wires from the regulator are grounded at one of the bolts that attach the regulator, that is where I ran the ground wire for the fan. The regulator had some extra material molded with the cooling fins that were an exact match for the mounting screws of the fan, (humm, forethought?) I drilled and tapped the four places for the fan screws. If your regulator doesn't have these places, use a metal tapping screw that is just larger than the space between the cooling fins and screw them in between the fins. I ran the positive wire of the fan into the positive/battery wire of the regulator where the regulator wires plug into the wiring harness (see picture) with an in-line fuse just like for a radio.

First picture is the plugs at the steering head where the regulator plugs into the wiring harness.


Second picture is the fan mounted on the regulators cooling fins.


Third picture is the fan again


Top view of the regulator and the fan (with the front fairing/windshield removed)


This picture is of the type of computer CPU fan I used. Notice how the attaching screws are screwed in between the cooling fins of the heat sink that attaches to the CPU (this heat sink not used on the 907 application, just for this example).


Next picture is schematic of voltage regulator and wiring that I have on my bike.

Bomber,
If you are cooking R/Rs, then I think you have something else going on.
1. Run with your lights on all the time. The heat is usually created when you are generating a lot of electricity, and are having to dump it. More load = less dumping= less heat. Unlike car alternators, motorcycle alternators just create more energy the faster the motor spins. (Car alternators actually regulate the amount they generate, as well as regulate the actual output)
2. check all your grounds, and other leads. Get rid of connectors and solder your wires.
3. Ground the case of the R/R with a separate wire and lug. Don't necessarily trust the existing wiring.

Its those odd voltage spikes that will kill the R/R. any intermittent connection will create problems. You may have to open up your cases and trace the wires back to the alternator to see that everything is solid down there.

But I like the fan idea too. If you ride in a hot area all the time, this will help.

Cheers,

I'd increase the thickness of the ground wires, too.
Really, on 907s the R/R was moved on front of the bike (on 750 and 906 it's behind the rear side fairing) to hit the flow of the air.
I'm not sure you'll solve the problem only with that fan.
Try with all the electrics mods suggested (sold the wires...)
Ciao

Thanks Guys, all your info is exactly what i was looking for.
I have taken it all on board and the fan is fitted, the wiring was replaced on previous RR replacement, and is heavy duty multicore.
I have used large bullet crimps on the cable ends, then solderd the connectors as well, then covered with heat shrink.
Also fitted the additional earth.
Thats a good point about the heat created if the battery is full, I have a feeling that because i kept the battery charged off the bike, i may have caused the failure.
My plan now is to let the RR do all the charging and only charge the battery off the bike when absolutley necessary .
The only bit i may have got wrong was where to pick up the 12dc for the fan, when i connected to the
+ve of the RR, the fan ran all the time with ignition off .
I managed to pick up a 12dc on the switched side of the ignition switch,there is a Molex connector (situated below the headlight) on the cables from the ignition, i was able to remove the pin and solder on a wire, Job done !!!
Also cleaned all the earths i could find.
Everything is back together and have had a short run this evening, so far so good .
Btw here in Scotland temperature is definitely not a problem rain is a big problem .Just had an idea hows about a water cooled RR
With the rain here it might just work

Thanks again

Bomber

I'm glad everything worked for you. I like these sites because of the pictures that everyone posts to help out with whatever. A lot of help sites don't have as many pictures and as the saying goes, a picture is worth a thousand words.
Good luck, weather is just now starting to turn for us in North Carolina USA.
du907

Here are some pictures, (if i manage to post them), of my labours !


Top Wiew

Fan Clamp made from old heatsink Fin

Fan & Clamps

Fan & RR in situ

RR Wiring

Additional Heat sink

View of additional heat sink


Regards

Bomber

Huh , the RR on my 906 is down back by the duo shock resiviour and Is not standard , dunno what it is maybe its cooler back there( as in temp not just a cool place to put it ha ha ) and has given no problems