More electrical gremlins

[jack737]

So this is again my '82 project, hasn't run in a very long time.   Replaced the wiring harness that was all cut up, put the carbs back in and after a few attempts it started up,  oh yah!  But still electrical issues, the horn doesn't work, and the right rear signal just stays on all the time.  Seems to be connected up right, took the left switch assembly apart and after chasing springs and ball bearings for a couple of hours put it back together.  No joy.  No power going to the horn, don't know how to test the horn button, seems to be only 1 pink wire going to it.
 Did a quick check of the voltage at the battery when it was running , didn't seem to be the steady 14 volts it should be.
 Any help would be much appreciated.

[fret not]

"Seems to be connected up right . . ."
Obviously SOMETHING is not right.  One way to tackle this problem is to get your VOM (Volt OHM Meter) and begin checking each wire, and comparing your harness with a wiring diagram. 
HORN BUTTON: check the contact surfaces of the button, check continuity of the wire, check the horn by temporarily connecting 12V directly to it's terminals to see if it works.  It is a process of eliminating the possibilities, one by one.

[jack737]

Ok got the horn working, tiny bit of corrosion under the spring.   I say it seems connected right because the connectors can pretty much only go one way, so I can't have hooked anything up wrong.  If the signals didn't work at all that would probably be easy to diagnose but why one bulb stays lit while everything else works?  I'll start with the wire tracing.

[Walt_M.]

Could be corrosion in the socket, could be too low wattage bulb. For a quick check, swap the bulbs side to side.

[jack737]

Ok,  so you'd think connect the green wire to the green wire,  nope connect the green wire to the brown wire.  Signals working properly now.   Started up and 14 volts at the battery.  On to the next challenges,  Thanks!

[WGuaire]

Good job on sorting out that.
  Now you can move on to the stator, regulator/rectifier, fuse box replacement, and possibly the coils.
My stock headlight bulb was terribly dim. The socket is an H4, but the bulb was antique. Rather than use an incandescent modern H4, I put in a superbrightleds.com H4 LED.
https://www.superbrightleds.com/moreinfo/miniature-and-subminiature-bulbs/motorcycle-h4-led-fanless-headlight-conversion-kit-with-compact-heat-sink-2000-lumens/3930/8566/
I put one of these in the brake/tail light =
https://www.superbrightleds.com/moreinfo/miniature-and-subminiature-bulbs/1157-led-bulb-dual-function-27-smd-led-tower-bay15d-bulb/2625/12880/

Even if everything is working alright, I would definitely replace the stock RR.
https://www.roadstercycle.com

[jack737]

Wow, that modern bulb in the big headlight shell should be pretty bright.  Hard to say if this bike will ever be ridden at night though.  Or ridden much at all.  Several problems to sort first.  Got it to run but won't idle. I think carbs will be coming out again but would be nice to do a compression test as well.   Tach is not working at all.

[fret not]

Have you checked the valve clearances?  Sometimes that can get out of whack and cause erratic operation.  Valve clearances tend to get smaller with wear with this system.

[The Prophet of Doom]

Got it to run but won't idle. I think carbs will be coming out again but would be nice to do a compression test as well.   Tach is not working at all.

Tach runs by counting pulses on front cyl, so if your tach isn't working, check your front cyl for spark before spending all that time on carbs. 
Of course your tach could be disconnected or broken - but it's a sign.

[Walt_M.]

So now for my usual nag, have you disconnected the rev limiter? It's the y/b wire at the TCI and when it fails it cuts the spark to the front cylinder. It has been a long time since mine failed and I can't remember if the tach still worked.

[WGuaire]

So now for my usual nag, have you disconnected the rev limiter? It's the y/b wire at the TCI and when it fails it cuts the spark to the front cylinder. It has been a long time since mine failed and I can't remember if the tach still worked.

I made a note of this and put this post on my storage hard drive. It's one less potential crap out. Plus, I don't exactly drive with the revs bouncing off the limiter anyway.

[jack737]

Yes the yellow black wire is cut. I haven’t checked the valve clearances because it looks like this bike has only 8900 km’s on it. Looks like it was crashed at some point which crushed the instrument cluster. But the broken speedometer came with it and it was reading 8900km’s. Of course that could be off anything so who knows. Probably been sitting for 15 to 20 years.  I could see a lot of crap around the exhaust valves so I’m thinking they aren’t sealing very well.  But trying to avoid taking the engine apart.  My compression tester doesn’t fit this plug size so I’ll have to make an adapter. Maybe do a leak down check.
I’m getting spark at both cylinders, the tach assembly came off another bike so not sure if it works, I have a second one so I’ll try that one next.

[jack737]

Tried the spare instrument cluster and that tachometer isn't working either, so I guess the issue is the TCI ? 
 The front carb looked like it was overflowing gas into the intake so took the carbs out.  Put them back in the ultrasonic cleaner,  I'm thinking there is a small hole in that passage at the bottom of the float bowl but I can't get a wire or any compressed air through it.

[kevin g]

There is a really small idle jet at the bottom of one of the small bores.  It gets fuel at the bottom of the bowel and sends to the idle circuit.  Mine was plugged and I finally got it cleared with a steel guitar string.  Mine did not overflow fuel, the cylinder would not run at idle.

[jack737]

I think it was overflowing because the top wasn’t seating on the gasket, seemed like the accelerator pump nozzle was sitting too high.  Anyway they’re clean now and no leaks so I’ll put them back in.
Hopefully it runs better, then I have to figure out why the tach doesn’t work.

[jack737]

Bike runs  great now! But still no tach.  Opened it up but I don’t see anything obvious wrong with it.