krza
XS650 Member
I'm really stumped right now with my '78 XS650 bobber.
I've wrapped up all the mechanical, and I wired the bike up using this diagram: http://www.xs650chopper.com/wp-content/uploads/2009/09/noid-chopperwiringdiagram.jpg
Briefly, the electrical system: stock points ignition, stator, rotor, coils, condenser. Kick only, no electric start. 12 V 7amp gel battery mounted under the seat. Tail/brake light, brake light switch, head light, and ignition. New plugs and wires. Solid state reg/rec from TC Bros. 20amp fuse between the positive terminal and the ignition and reg/rec.
When I wired the bike according to the above diagram, the charging system would not operate. The bike kept dying. At my wits end, I decided to swap out the nylon screws I put on the stator for the stock metal screws, and then grounded the black stator wire to the bike ground (instead of hooking it up to the keyed power wire as in the diagram). The bike ran, and it charged. 13.2-14.4 V at the battery when it was idling. I figured I had fixed it.
Lately, the bike was having an intermittent problem with voltage. Sometimes with the key off, the bike would have 12V DC at the battery (according to digital multimeter). When the key is turned on, the voltage drops to 0.10V-3.10V with no rhyme or reason. Voltage problem comes and goes. At times, it will kick and run. I can take it for a ride, sometimes for hours and miles, sometimes just long enough for it to die 20 blocks from home, with low voltage again. After a while, the voltage might be fine and I can kick it again; sometimes I push the bike home.
I've gone through the entire electrical system, thinking there is a short or a draw somewhere. I've slowly eliminated different systems: brake light switch, tail/brake light, headlight, condenser and points, coils, reg/rec (I even swapped in another solid state reg/rec I had). Still, low voltage with the key on. I even replaced the ignition with a two position on/off switch to eliminate the possibility of that being bad. No dice. Still low voltage. Yesterday, to eliminate the possibility of a bad solder or connection (all connections on the bike are soldered/heat shrunk) I re-wired all the essential charging system components with a two position on/off switch. Brand new wires all around with the exception of the stock harness going into the stator from the reg/rec (3 white wires, one green, one yellow, one black). Still low voltage with on/off switch turned on.
At this point, I'm stumped. It's sunny. I need to ride before the Portland rain returns. Help me out.
