I'm reviving an old Yamaha XV535 Virago. It's running and passed roadworthy inspection yesterday, but it has one remaining issue before I take it for a real ride - its not charging enough. Battery voltage increases from ~12.5V to ~12.9V when I start it. Should be ~14V.
A lot of the electrical connections were very crusty - I've cleaned them as best I can with contact cleaner and mechanical scraping. The 4 pin connector from the pickup coils to the loom was particularly nasty and has been hot and I could not clean it enough so replaced it with a (knock-off) Deutsch DT connector and that's working well. The connector from the stator to the loom has also been hot. I've replaced the plastic shells and cleaned the connectors as best I can but I feel this connector may still be the source of my low charging voltage and I plan to replace it.
My options are 3 x generic bullet connectors or a single 3 (solid) pin Deutsch DT.
I know the DT connectors are not intended for "power" applications, but I can't find anything to say if the current on each of these wires from the stator would exceed the ~7.5A they are supposed to be rated for.
Thoughts?
Check that each leg of the stator is good by checking that each yellow wire has about 0.3 - 0.4 ohms resistance against the other yellow wires, and that none of the yellow wires have continuity to ground. If one leg of your stator goes bad, it can overtax the remaining leg(s).
Corrosion causes resistance, which creates heat and lower voltage. Are just the connectors corroded, or are the wires also corroded?
To clean connectors, I use DeOxit. Spray it on, then plug and unplug the connector a few times. If that's not enough, I use a soft, brass bristle brush. If that's not enough to clean the connector to gleaming, then I replace the connector.
Incidentally, it's common for motorcycles to barely charge at idle. You often don't hit a 13.2 - 14.4V cutoff until a few thousand RPM.