Tach needle jumping around...

[JonnyO]

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.

Is there anything else I can use to clean it or another method? I can get it off but don't have the Evapo stuff.

[JonnyO]

I would not discard what Motoman (Brant) suggested. Those welds in these old controls can break loose over the years. Might want to take a look in there, While you are it you might want to check the left hand controls too. I am thinking at this point that your problem lies in dirty connections or a voltage regulator/rectifier slowly going bad.

OK thanks. Appreciate you seconding his suggestion. Guess that's next as I've still the faulty tach reading. Now to figure out how to do that.
Funny. I found a box with new start/off and headlight switches. Might be for a 650 I had though. Thanks again.

[cajun31]

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!

I would not discard what Motoman (Brant) suggested. Those welds in these old controls can break loose over the years. Might want to take a look in there, While you are at it you might want to check the left hand controls too. I am thinking at this point that your problem lies in dirty connections or a voltage regulator/rectifier slowly going bad.

[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!

[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.

[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.

[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?

[DEEBS11]

[DEEBS11]

Here is a better explanation of the diagram.

[JonnyO]

Here is a wiring diagram for your bike in color. 80sg_81sh_wire.pdf

Great. Colored hieroglyphics. JK
ANYWAY I used the contact cleaner on the two connections suggested in the maintenance post by XS11 from 2002. Nope. Didn't work. I suppose I'll now have to try to figure out how to follow his instructions on what voltage should be
on each wire. Rats.
I did check the battery off the trickle charger last night- 12.89 now so I guess the battery is still good.

[cajun31]

Here is a wiring diagram for your bike in color. 80sg_81sh_wire.pdf

[JonnyO]

Hmm? I see a hieroglyphic drawing. From inside the tomb of Keops?
But seriously I've no practical knowledge of this " stuff ". I'm supposing that the W, B, BR are representative of White Black and Brown wires. 3 Ws. Does that represent the plug under the fuse box? I'm going to Lowes to get some circuit cleaner to try and clean out as the one post said cleaning the two plugs with those W and Br and G color wires under the fuse box solved his tach issue.
Just a shot in the dark.

[DEEBS11]

[JonnyO]

That sounds normal. There are six cells in a battery. Each cell carries about 2.2 volts. Doing the math that comes to 13.2 volts. That is approximately what you will have on a fully charged battery. It only drops after trying to crank the motor. 14.81 is also good which shows that the alternator and the voltage regulator/rectifier are doing there job. When you stated 15ish that indicated exceeding 14ish which is not good. Back to checking your settings on what Phil said to check on your tachometer problems.

Aye aye. At this point I'm leaning towards buying a good tach from a member-just to rule it out.

[cajun31]

Maybe the trickle charger has eventually done something not good? Battery shows 13.18 after unplugging charger and revs up to 14.81 on choke.

That sounds normal. There are six cells in a battery. Each cell carries about 2.2 volts. Doing the math that comes to 13.2 volts. That is approximately what you will have on a fully charged battery. It only drops after trying to crank the motor. 14.81 is also good which shows that the alternator and the voltage regulator/rectifier are doing there job. When you stated 15ish that indicated exceeding 14ish which is not good. Back to checking your settings on what Phil said to check on your tachometer problems.