UP IN SMOKE!

Vince Lupo · Post by **Vince Lupo** » Sun Aug 09, 2009 7:05 pm

Sounds good.

The reason I ask about the underside of the seat is that the exact same thing happened to me on a 600 Yamaha Radian I had. I had an intercom system hooked up to the battery, and the connection to the positive terminal was touching the underside of the seat, and it started smoking. Fortunately the only thing that got burned was the wire to the intercom.

e3steve · Post by **e3steve** » Mon Aug 10, 2009 4:05 pm

brewsky wrote: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?

Brew, the metal backplate is to assist the heat transfer to a heatsink and is electrically isolated. The Radio Shack is pretty OK, but opt for a 25A rather than a 15A; it won't run as hot, as its diodes are of a higher current capacity.

Unless you intend to 'show' your bike, don't bother with the old selenium type. It's almost, well, pre-historic, technically speaking!

Rgds,

Steve

brewsky · Post by **brewsky** » Mon Aug 10, 2009 5:01 pm

E3,
Thanks for yor help...you were right on the diagnosis!
Got the 25A Radio Shack model, robbed an old heat sink out of an old computer, a little wire patching and she started right up.
Puts out about 12.9 volts no lights and 13.5 volts with lights revved up a little.
Before and after pics below:

Gunner_CAF · Post by **Gunner_CAF** » Mon Aug 10, 2009 9:19 pm

Nice work! If you ever want to go back to the stock look, Retro Bikes makes a new (non selenium) rectifier that looks like the genuine item.

Gunner

e3steve · Post by **e3steve** » Tue Aug 11, 2009 3:10 am

E3,
Thanks for yor help...you were right on the diagnosis!
Got the 25A Radio Shack model, robbed an old heat sink out of an old computer, a little wire patching and she started right up.
Puts out about 12.9 volts no lights and 13.5 volts with lights revved up a little.

Sweeeeeeet. Nice job! Good to see others using decent protective sheath over the cables. One observation: I'd be inclined to change those uninsulated push-ons for the insulated variety..... Better safe than sorry, me ol' mate!

brewsky · Post by **brewsky** » Tue Aug 11, 2009 4:29 am

Thanks for the replies and help!
This forum is great.

E3, you are right again on the connectors, I just tend to use what's laying around at first. Eventually I will get or make up a new harness front to back.
After this episode, I am gunshy about the coil and condenser.
Will be looking for a more modern version of these as I plan on riding this instead of going the show bike route.

Gunner, I have used Retro Bikes already and was well satisfied.

e3steve · Post by **e3steve** » Sat Aug 15, 2009 11:17 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: just measured my CB stator: pk-bn = 1R(Ω), pk-y = 1.6R & y-bn = 2.6R. This means that the CB diagram* must be correct and that my stator is a touch unbalanced, if within tolerance, with coil pair#1 being 0.6R, #2 being 1R & #3 being 1R.

Abstract: pk-bn routes via coil pair#2, pk-y via 1 & 3, y-bn via all 3 pairs. The pairs are diametrically coupled within the stator.

*concerning the alternator coils' internal connections!