Tach needle jumping around...

[JonnyO]

Ok. With the key on the B/Br give me a reading of 11.22.
With the bike running I get 12.7 with the white wire. No reading at all not running.
What say you guys?

[motoman]

JonnyO, being not sure where your at with the electrical system, A very common issue is the STOP/RUN switch which completes the running circuit. Due to exposure to weather elements, internally the contacts will cause a voltage drop. Unplug from harness wire, remove switch from handle bars and drop it in a cup of Evapo=Rust for a couple hours then remove it and wash it out with water in your house sink. Blow it out dry with an air hose. Re-attach it all to handle bars and this will eliminate any unknown voltage drop.[ Doing this will also brighten up the red insert of the switch]. BTDT, so give that a go.

[DEEBS11]

Ok. With the key on the B/Br give me a reading of 11.22.
With the bike running I get 12.7 with the white wire. No reading at all not running.
What say you guys?

When you check the white wire to ground with the engine running your meter should be on AC and not DC. It's an analog signal not a direct current signal. It only works when the engine is running and generating AC voltage (before it is rectified in the regulator). I am going to guess that this signal is OK. My point was more pointed in the direction of checking to make sure the connections were clean. Especially the two ground connections on one of the screws holding down the regulator under the gas tank.

[JonnyO]

Awe hell! I just spent 20 minutes writing out a reply and wiped it out with one push of a button.
Anyway, I'll check the regulator screws. Thank you!