Motorcycle Repair: Honda 1974 CL200 wiring


Question
(I intend brevity here)
Shop owner, mainly SUZ GS/G models, decades of experience in electrical issues, all successes. Owned/rode this CL200 for 15yrs. Stumped now, probably a neophyte mistake, but too close to trees to see forest.  Have & followed OEM Shop Manual circuits for following issue....  It last ran very well 15 years ago with original OEM harness. Installed new battery & without key turned on it cooked the diode!  JAN '14 got new diode, chased the circuits (continuity, correct connections, continuity), all OK. No go. built new harness since OEM connector joints corroded & stiff wire insul, used "near-new" salvaged Honda wire from my parts bin. With nothing else done it started on second rev of starter & became mosquito fogger.  Overhauled engine, complete top end.  Hooked it all up, turned on the key, no juice anywhere.  Ignition key has correct continuity, battery fully charged.  Replaced questionable regulator.  No go. Got used Ebay harness & replaced all connectors on it. No go. Fuse OK. Continuity OK. Lights OK wired directly off new battery. From years past I believe I remember some weird thing about connections at the brown/white lines in the headlight area, and there has always been an unused brown wire in the orig main harness and the recent Ebay harness but is not shown on OEM wiring diagram.  Only suspect left is the alternator, but it seems not to have any meaning in making juice flow (on SUZIES the 3 alternator wires can be hooked to any of the 3 wires coming out of the harness, same with Honda? Wires have no jacket color here).  THE QUESTION-- what the hey is going on here?

Answer
Bill, reading between the lines, I assume that you installed the battery backwards and fried the rectifier and blew the fuse. I don't know if you painted/powdercoated any thing when the motor was out, but it sounds like a bad ground somewhere.

Honda wiring colors are consistent from start to finish, so start from the beginning and work out from there, after you have checked all of the ground connections first.

Power to the ignition switch comes in on the red wire and is distributed on the black wire coming back out. The other wires are for the lighting functions, feeding the headlight switch, horn, neutral light and brake light switches.

Honda went to a "always on" headlight system in 1975, so the harnesses are different than the pre-75 versions as are the dimmer switches. NO POWER ANYWHERE, as you describe it would be fuse-related in most cases (or poor ground). Check the fuse holder to see if the wire connectors are damaged or overheated causing poor fuse connection. Fuses can get fractured and look good, but have no continuity.  The brown/brown white wires are to add another power leg to the rectifier when the lights are turned on. If the switch or the wiring connectors fail, you will not charge the battery sufficiently when driving the bike. These wires don't affect power to the system, unless they are shorted out.

Use a good 12v test light grounded to the engine/frame and start with the battery, check power through the fuse/fuse holder, then onto the ignition switch, through the switch and into the the various connections inside the headlight bucket. The black wiring is switched 12v power, the black with white striping is for the ignition feed to the coil. GREEN wires go to ground. Green-yellow wires are for the brake light system. There are often spare brown wires connectors in the headlight as they are used for pilot/parking lights in countries where they use an additional light in the headlight reflector.

I hope this is helpful for you..

http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class for other diagrams/views of the wiring diagrams.

Bill Silver