UP IN SMOKE!

brewsky · Post by **brewsky** » Wed Aug 05, 2009 3:25 pm

Finally got my tags and ready to go on first real test ride to sort out some plug issues,
and smoke starts pouring out of the battery box while revving it up to clear the plugs!
The hot wire (unfused) from the battery to the rectifier is fried! Melted the rectifier connection plug, but the rest of the wires seem unfazed except where they were close to it.
Had been on a couple of short neighborhood rides previously with no electrical issues.
Everything electrical as far as I can tell is original..condenser, rectifier, coil, stator, etc.
(66 305 dream)
Any ideas on the culprit?

e3steve · Post by **e3steve** » Thu Aug 06, 2009 5:58 am

The rec is shagged; most likely, at least two of the diodes between the positive output pole -- there are two pairs, each in series and that series paralleled with its neighbouring pair (see pic) -- and ground pole are shorted.

Replace the rec and the burnt cable; check close-proximity cables' for their insulation integrity.

brewsky · Post by **brewsky** » Thu Aug 06, 2009 9:54 am

THANKS for the reply. That's what I was hoping for, way cheaper than a stator hopefully!

Just in case, do you happen to know the stator resistance I should check for?
TIA

e3steve · Post by **e3steve** » Thu Aug 06, 2009 11:52 am

Brew, all stators should read Open Circuit / no continuity / infinity (∞) to ground; a C/CA stator, I seem to recall, has a reading of between 1 & 3Ω (1.6Ω springs to mind, for some reason) across yellow & brown. Whatever is is, it's pretty low -- practically dead-short. If yellow to brown = R, then pink to brown = R∕2; that's the way the 3 coils are internally linked. The CB stator is different: pk-bn = R, pk-y = 2R & y-bn = 3R.

All readings should be checked after disconnecting those colours at the main harness-to-motor junction.

UPDATE posted 15 Aug.

brewsky · Post by **brewsky** » Sun Aug 09, 2009 5:23 pm

THANKS, E3,
I'm getting ready to try the Radio Shack 3 dollar rectifier before I spend big bucks on an OEM type.
Will have to replace some wires that shared the lower end of the harness, but the rest seem ok.
Maybe it won't be as bad as I originally thought.
The rear of the rectifier has a metal plate but it doesn"t show continuity to any of the 4 terminals (including the ground terminal).....wonder if it needs to be insulated from ground on the bike?

Vince Lupo · Post by **Vince Lupo** » Sun Aug 09, 2009 5:56 pm

Just out of curiosity -- did you ever figure out the cause of this situation? If not, is it possible that one of the battery terminal connections could possibly be touching the underside of the seat? That might be something to check....

brewsky · Post by **brewsky** » Sun Aug 09, 2009 6:37 pm

Most likely, E3 nailed the problem as bad rectifier shorting the + battery terminal to ground thru the rectifier.
I will see if I can confirm this with a meter and let you know.
I could find no other short to ground anywhere in the harness.