I'm happy to report that the SL100 continues to progress and the charging system is now working fine. As reported earlier, The stator had checked out (there are differences of opinion on how to check, I used the method checking for continuity between the three possible wire pairs and also ensuring that none go to ground) and then tested the rectifier, which showed to have one bad diode. I decided to try out the Oregon Motorcycle Parts rectifier, it is tiny in comparison to the original unit but is supposed to be far more durable. I used the original mounting bracket and location, installed the wires into the connector to match original configuration, put it all back together, started it up and.....nothing???? Still not charging. WTF?
So I'm looking at the way it is wired, it does have a ground wire leading to the base, I had cleaned the base and mounting plate, should have a good ground, but then I realized the rectifer mounts to the air box and it's mounted on rubber grommets! Ok, so I make an auxilliary ground wire, hook it up and suddenly she is charging beautfully. With key off it was at 6 volts, key on and engine running at 7.75 volts. Just for grins I decided to try something I had read about, pairing the yelow wire with the white wire and the running voltage jumped to over 8.5. I decided that since this unit does not use a voltage regulator to only go with the factory yellow wire.
New rectifier (with auxilliary ground)
The increased voltage definitely helped the performance but still had a pretty good burble in mid range, so I took the slide out, dropped the needle to the bottom adjustment and tried again, now it is running pretty good with only a slight mid range burble. The new needle and nozzle should arrive have next week.
I'm now tidying up the wiring, getting ready to pull and clean the clutch plates (they are stuck) and turn this bike over to the duaghter so she can ride it! With this phase of the project winding down (remember it is going to get hot rodded for Vintage MX) I will start shifting my focus back to the 350 twins again.