I just recently got my CA77 running, and attempting the various suggestions on this forum, I was letting the engine warm-up so I put the key in the lights on position and left the dimmer switch in the neutral position, thinking that the battery would charge better while idling. Then the smoke started to bellow out of the area of the rectifier. I caught it early enough where as the wires didn't melt. But without duplicating what I had done, I have no idea why it would smoke or from where.
Could this be the result of a bad rectifier, stator/rotor? Everything works as it should, the hedalight on hi or low works. It's just when I have the dimmer switch in the neutral position does it smoke.
Thanks,
Tinman
Charging, the light switch on and the dimmer switch neutral
A shot in the dark: legend has it that some US states disallowed the 'neutral' position in the dimmer switch; in such cases the passing of the switch overcentre presents an overlap, thus lighting both hi and lo beam filaments. This could overtax an ageing selenium diode rectifier, assuming yours is the old, red OEM type.
I'm sure you'd have noticed if both headlight filaments had remained on, as opposed to just the parking light neutral position that many of us 305-ers are used to? Just a thought. Note that the rectifier's positive tag connects directly to the battery via no fuse link; therefore it's likely that the smoke is emanating from the rec itself or from the red/white wire (which is covered by a heat-resistant sleeve and, thus, won't immediately reveal a meltdown). Check out this post; consider installing a 25-Amp fuse.
e3steve,
Thanks for the information. I strongly suspected that it was the rectifier, and yes, it is the original. I do however have ordered a silicon based rectifier from Oregon Motorcycle parts. I pulled the harness apart at the rear and didn't see any area that may have been damaged. I will closely take a look at the red/white for any damage. When I selected the lights on and neutral position on the dimmer I didn't see the headlight or tail lights on. I'm hoping that it's just the rectifier. I did however try to measure any resistance in the rectifier and had such erractic readings at the different terminals (battery disconnected). Yel to brn was 35ohms and yel or brn to red was zero. I reversed the leads and it read zero to all 3 terminals. I'm not sure if I did this correctly as anything electrical is my weakness, but we shall see how it changes when I swap out the rectifier. I'm also reading 12.35dcv at the battery while the engine is running, and with it stopped, the reading is 13.5dcv. I'm not sure how that's happening as I'm trying to read as much as I can and understand the charging system. Thanks again, Tinman
Please check your bike's main fuse, in the red wire, close to the battery; it should be a correct 15-Amp fuse and not a nail, screw or tinfoil! If there's a short circuit or overload when the dimmer switch is operated then that fuse should fail. If you lose all lights in the dimmer switch's neutral detent then I suspect the problem goes deeper.
Let me know.....
Well, the fuse is good, so we'll just have to wait on the new rectifier and see if it solves the problem.
I looked at the rectifier from Charlie's place too. I think that is a better choice, but the $$ chased me away. I may end up with Charlie's rectifier in the future as he also sells an electronic ignition unit which I'm considering and the electronic ignition won't work without a rectifier with a voltage regulator. It would be a nice upgrade. I once restored an old MGB and installed a Pertronix electronic ignition on it, it worked under the same principle (Hall's effect) as what Charlie's advertises. Solved the crappy Lucas ignition woe's.
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