83 cb650sc charging issue

[lordmik]

This is a great forum! Glad I came across it. I've owned this 83 for about a month now, put about 700 miles on it so far, lovin it. However, recently it's not charging the battery very well. It's charging at just over battery voltage 12.5-12.6V at around 4000 rpms, and not much more than that if revved higher. I don't have a manual yet, but the little bit of testing I've done (I'm an auto mechanic by trade) have led me to believe the r/r is not doing it's job. I've read a few places on this big ol 'net about people buildin a r/r with auto style parts, but I'm a little skeptical. Has anyone attempted this? With what results? Seems pretty straightforward really, rectifier to change the 3 ac from the stator to dc, and a regulator to keep the voltage right. I got this bike for next to nothing, and I'd prefer if possible to keep about the same amount in it. Thoughts? Suggestions? Thanks in advance.

Edit... Let me add another oversimplified question to this. A rectifier is simply a set of diodes, right? So if I put a diode on each of the three yellow output wires from the stator, and wired them into a separate voltage regulator, is there any reason that wouldn't work?

Michael

83 CB650SC Nighthawk

[ROJ]

I'm not sure about buildling one from auto style parts, but you can get new ones for ~$100 that fit. Other than that there are always salvage yards, but you're taking a gamble with used electrical parts. What testing have you done with the R/R to date?? I don't have a 650 manual handy, but someone on here wiht one should have all the correct resitsance readings to test the R/R.. I'd also check the rotor too. For that take the plug coming from the A/C generator and check that the 3 yellow wires have continuity with each other, but not with ground. Also check the resitance between the black and white wires, anywhere from 3.6-6.6 ohms and its good.

[ExTex]

To build a rectifier/regulator for the Nighthawk is difficult.
There are 6 diodes (2 per yellow wire) and the regulator.
They have to be mounted on a good heat sink since the regulator must be able to short to ground
the excess current not being used by the bike.  This could be 20  amps if your headlight burned out.

The R/R has to be well insulated to prevent shorts and be able to handle rain and cold as well as heat.

Check the R/R as per your manual and www.electrosport.com

If you need a stator or R/R, buy a new one instead of a used one that is as worn as the parts that failed on your bike.


Ride Safely
 

[lordmik]

The building a r/r isn't difficult, nor is the wiring. Just wondered if anyone had done it and with what success. However, after much reading on this and other forums, I'm not entirely sure that's my problem not.  Seems there are a lot of issues that can arise on these chargings systems. I guess I'll need to do some more research until my brain is finally saturated, then try to figure out exactly what is wrong. Thanks for your replies. Time to hunt for a wiring diagram. 

Michael


83 CB650SC Nighthawk

[lordmik]

Update... Fixed. That connector from the r/r to the stator evidently had a bad connection as someone had mentioned on another post in another thread. I cut and soldered the five wires and lo and behold, it was good. Charging again. Just off idle went to 13.1v and was easin up towards 15v around 6k. Battery's a little weak so I'm hoping that's the reason for the higher voltage output. I'll know more when I ride it, but this is mucho better than I was getting. Thanks for this forum. Lots of good info in here. Now if I can just figure out why I don't have 4th gear....


Michael

83 CB650SC Nighthawk