Hello all, first post on these forums. Though I have read plenty from them without posting myself..I guess that's how I got this far.
So, I purchased a 1980 Honda CB750 DOHC bike. She looks nice, engine runs great, carbs are good..just a good bike. Except the electrical. That's the stuff of nightmares.
The basic problem is the typicall "my bike wont charge". I have read and followed many other instructions on this topic, including this:
http://www.cb750c.com/publicdocs/CB1000C_Manual/Chapter_18_Battery_and_Charging_System.pdfand thought I had my issue dialed: the rotor was bad. It tested at .03 ohms across the two rings. Bad rotor, problem solved. Or so I thought. In addition to this, both of my spark units (the silver devils on top of the battery) puked out this strange black goo the first time I ran her around..I can't figure out if this would have anything to do with my future problems.
Purchased a new rotor & regulator/rectifier (didn't test the old reg/rec, but I hear a bad rotor can break a rectifier and vis-à-vis) Installed both (rotor tested good prior to installation, torqued rotor to 70 ft lbs with a bit of loc-tite to keep her snug), cleaned all the connectors with some Contact Cleaner, put in a charged working battery, fired it up, and measured 12.5 volts between the terminals with the bike idling. This would rise slightly to 12.8 volts when the bike was revved to 3-4k. Much more then I was getting before (11 ish), but not the 13 - 14 I wanted. But the bike would finally make & hold a charge and could ride without draining the battery. Ran it like this for probably 30 minutes.
I took her out for a spin and burnt the main fuse (fusible link?) that runs between those two little screws. Spliced in a piece of copper wire, fired the bike back up and forgot about it. Now on my way back home the bike again started to lose charge, the motor began running very rough and when I stopped, she wouldn't start up again. Son-of-a-gun. Got back home, pulled the stator/rotor cover, and the rotor now tests bad, zero resistance! Upon closer inspection, I can actually see a point where the wires broke/cooked. Okay - why?? Why the burnt fuse, the burnt rotor, the melting spark units?
I tested my stator now - just the resistance between yellow wires. Everything was around 4-6 ohms, so I think it should be good according to this video:
https://www.youtube.com/watch?v=U-UwX3xwHfw brushes also look good, well longer then the replace-me marks.
I am beginning to think there's some weird thing in the wiring, I just cant find it, nor do I know how to test my harness in general to figure out if there is a problem.
Any help, or ideas for where & how to test would be much appreciated. Thanks!
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