Just wanted to give Tony at OMP a huge thanks for helping me out with some electrical issues I was having with my '73 750. It also involves a little story that had me perplexed and will hopefully help others.
I had run it with a Vetter and a juke box for years without issue.
This is when I lived in the Midwest (MI) where the roads are mostly straight and lit.
However, the twisty, dark, and often cliff-riddled roads of the Pacific Northwest are a different story!
So, after seeing a 2 volt drop at the headlight plug, I decided to add headlight relays to see 12 volts at the plug.
So I got a couple relays, wired the first one to the headlight on/off switch, and wired the second one to the hi/lo beam switch. Actually, I only had to wire the hi beam and left the lo beam as the "normally closed" default on the relay.
Everything worked great, when I turn the main switch on, power flows from the battery through the first relay and into the second, at which point the normally closed circuit powers the lo beam. Switch the hi beam and viola' a working system.
Go for a nice long ride with new found confidence, and was lucky get home with 9 volts left in my battery!
Charge and check and the specific gravity and it doesn't even float a ball!
O.K., new battery, charge system check by the book, voltage was down, amps were much higher. (big hint there)
Hmmmm...
How about an electrical budget analysis?
I hook up the amp meter and start turning stuff on/off to account for everything.
What's this? with everything off and the key on, I'm pulling 1.6 amps! Finally, that must be the culprit!
After head scratching/hair tearing checking, measuring plugging and unplugging and then starting over again 3-4 times, I realize it's the field coil I am seeing, and that I don't have a short/load I shouldn't have! The field coil is apparently powered up when the key is on. It's value is 7.2 ohms which makes for ~1.6 amps @ 12 v.
So, on to a charging system test. My volts are down and my amps are up through the rpm range.
So now I'm really stumped. I pull apart every connection I can get to (except THE one) and scrape, sand, clean, bend and tighten them.
Made no difference. Crap, the Memorial weekend is coming and I'm supposed to ride down to Cal!
Why are my volts down and my amps up?!???.
In desperation, and suspecting my charging system, I call Tony about his solid state reg/rect. Being that I'm local and he's a down to earth rider of old bikes as well, he says "Bring it over and we'll see what we can do. So I go over there and Tony sits down next to the bike and starts cutting and replacing connectors. We pull the airbox to get to THE one that I didn't get to. It's the first plug the yellow stator wires see as they exit the alternator.
Lo and behold, one of the yellows has overheated and melted itself into the connector! Turns out my system was only getting 2/3rds of what it needed.
Tony replaces that and says "that was your problem and your good to go".
What a straight up guy, fixes my bike and tells me I don't need to purchase anything!
Of course, after that I just had to have his solid state will-outlast-your-bike reg/rect unit!
So he whipped one in there using the existing mounts for the old units. With it's increased output
(and dielectric grease packed connectors) I should never have a power defecit again!
Tony explained that it doesn't put out any more power than stock, it just starts making full charge at 1200 rpm or so.
Man what a difference, my blinkers blink away like a modern bike with "old school" incandescants, while idling at 900-1000 rpm! He says I could put a 100w light on there (if it were legal
)
As a side note I learned a couple things.
!. When a switch (headlight/hilo switch sees 3-5 amps through ot for 37 yrs, and then you try to power a relay at 150 milliamps through it, that it needs to be thoroughly cleaned/reconditioned.
2. When you add additional electrical load, connectors with resistance will see more heat (causing one to fail in my case)
Anyway, another huge thanks to Tony and I helps this helps someone somehow!
