Charging and regulator questions and answers

[90_907ie]

Hi All, Just wanted to share and ask a question. My 907 has always had a weak charging system, but it finally needed to have something done about it. I had to get a new battery because I charged my old one to death, but anyway even with a new battery I could see the brightness of the lights change as I would rev the bike up. I did voltage checks from the battery and here is what I came up with.
12.4 V at ignition off.
11.9 V at ignition on
12.7 V Bike running at idle
13-14.5 V at 2k rpm
from 2k RPM the voltage drops, the higher I rev the engine! So the numbers seem to be fine, but something is clearly wrong.

Also keep in mind that the the brightness of the lights are pulsing the whole time and pulsing faster the higher I rev the engine.

I noticed last week that the connectors for the stator were warm, although the wire was not so I knew I had to redo those connectors, but I was not prepared for the mess I found under the black electrical tape on the main wires going to the regulator, which I think is an electrex rr51 since it has a white wire instead of brown and pink and no numeric markings. Anyway the 2 yellow wires and the red wire were very corroded and had obviously gotten warm. So I will be doing some soldering and shrink tubing soon.

Anyway that is the answer part, as to why the charging system was not working up to par.

My question is in the troubleshooting I will be doing, I have obtained 2 honda cx500 rectifier/regulators since I heard that they can be used on my 907. I suspect that a rectifier has gone out on my current one. But I can't seem to find that information any more on how they should be connected. I hopefully will just be doing testing, but may need it longer term. Does anyone have any experience with fitting the honda R/R to the 907? If so I have a couple of questions.

Thank you, David

[jcslocum]

I can't help you with the Honduh parts but getting a wiring diagram of that model will help you know how to wire it up.

Make sure to clean all of the grounds (earth) connections starting at the battery. There are some that go from the frame to the engine and can create issues witht he charging system. Take nothing for granted and undo, then clean them all.

[ducapaso]

from 2k RPM the voltage drops, the higher I rev the engine! So the numbers seem to be fine, but something is clearly wrong.

Also keep in mind that the the brightness of the lights are pulsing the whole time and pulsing faster the higher I rev the engine.


I suspect that a rectifier has gone out on my current one.

It actually sounds like a regulator blowing.
Search for "electrex" in farmer posts before doing any mod to your bike!

[ducbertus]

I agree with Slocum to clean all the connectors. The orginal ones coming from the genarator are prone to fail, causing disaster. Also chech the earthing of the regulator. You can add a wire directly from the cooling fins (drill and tap a hole)
to the central earth point on the upper beam of the main frame.

ducbertus

[ducinthebay]

The best connector is no connector.
Solder is much more secure choice, especially when dealling with the charging circuit. It certainly doesn't take much to do it, or redo it later. All connectors are suspect, especially 20 year old Italian ones.

And yes, make sure its grounded well, as Ducbertus mentioned. Check that your ECU is also grounded.

Cheers.

[90_907ie]

Thanks again all for the input. I have ordered a replacement Electrex unit. I wired in the Honda R/R for testing and sure enough the lights stopped pulsing and were steady. The engine sounded stronger and more solid. The only problem is that the honda unit allowed the voltage to get to 16V at 5k RPM, so it served it's testing purpose, but won't work long term obviously. I have also started getting rid of the connectors and soldering and heat shrink tubing all the charge circuit wires, better solid soldered than corroded.

Thanks again all for the advice