1982 Seca XJ750, ZRX1200 has company now.

[Bonz]

I think the logic is a bit different than the sensor is at 12V vs the voltage on one cell. I honestly don't remember the whole story. The XJ forums can serve as a refresher. I think the sensor itself was around 1k ohm when the electrolyte was present, and the cluster reads the voltage more than the current.....or something like that.

Thanks! That's what I was trying to say in the last post. As long as the voltage is higher than what a single cell should be, the "Batt" warning will be off to my logic.

Even though it functions when all is well connected to the positive battery terminal, a single cell would never feed 12 volts to the cluster. As has been said, if something goes wonky, not sure what would happen or if I would like what happens given it's a perfectly functioning 44-year-old cluster.

Back to the question, running it off of the battery with a fuse in line and a resistor, what size fuse would you all go with? A 5 amp, 10 amp etc?

[Radioguylogs]

I would choose the smallest available fuse, like 1A or less.

This circuit will draw negligible current.

[Bonz]

Thank you for that input!

Found another inconsistency with the carburetors today. Number four is from an early XJ650, needle was also from the XJ650, wasn't paid attention to by the dealer who rebuilt the carbs for my uncle. XJ650 needles are much richer than the XJ750 needles. Changed it out for the proper needle today from a spare carb. Slowly sneaking up on getting this thing dialed in from all angles lol.