Topic: Electrical problem

[egar]

Hi. I'm a newbie to the cb thing. My daily ride here in Florida is a ACE 750. Bought a 1978 cb550k last week with the intention of resurrecting it. Took the carbs off and cleaned them thoroughly, bought a new battery, installed new plugs and the bike won't start. It turns over OK, but my Harley-riding neighbor thinks it's an electrical problem. He used a test light and didn't get any spark at the coil nor the points. It doesn't appear the wires are juiced going to the coil. I've looked at wiring diagrams and read this site thoroughly, but I don't know what to do. New rectifier? New coils? New points and condensers? 

[Bob Wessner]

Could be corroded connectors in the wiring harness. Try pulling them apart one at a time, clean and use some dielectric grease on them before reconnecting.

[egar]

Wow. I am loving this site. That is a fast response. I will definitely do that. The bike sat for a few years in a shed and the humid weather down here has caused some corrosion here and there. Thanks much!

[TwoTired]

Do make sure the STOP-RUN-STOP switch on the handlebar is in the RUN position.

[polishbeer]

First you've got to establish static timing.  Easily done with a couple lengths of wire and a 12v lightbulb soldered and taped between them.  Follow the instructions in your repair manual for cleaning and setting the points gap and static timing.  If you can't get a spark that way then there is the cheaters way to find out if there is a break in your wiring harness.

Disconnect the blue and yellow wires from the coil and also from the points.  Get two three-foot lenghts of good wire, some alligator clips, and create a jumper from the blue coil wire to the blue points wire, and a jumper from the yellow coil wire to the yellow points wire. This eliminates the wiring harness completely from the equation.

J AkA p

[oldbiker]

I agree with all the above BUT first thing is the points. They may look good but clean them with a little fine emery or wet and dry. You will be amazed the difference this makes.

[eldar]

If this bike has been sitting for a long time, I would just get new points and condensers. Install and set timing.

If still no fire, make sure you are getting gas. Petcock could be clogged.

Make sure you bench synced the carbs after cleaning.  How did you clean the carbs?

[egar]

Still working on my problem. Here's another question: Since the coil and points don't seem to be getting any juice, I checked the wiring diagram. The black wire going to the kill switch has power, but the test light didn't come on for the black and white wire going from the kill switch to the coils - even when the key was on and the kill switch was in the "on position". Could it be a faulty kill switch?

[egar]

Eldar,
I think I will just get the points and conder kit. Everyone on this site seems to think that it is a common electrical problem. I removed the airbox and carbs and cleaned the carbs thoroughly with carb cleaner. I made sure to remove the float bowls (which were filled in the bottom with a red clay-like residue) and the cover on top of each carb. I also removed the skinny screw inside the carbs that have the tiny pinholes all over them and made sure they were clean. I flushed the gas tank with carb cleaner, then dish detergent and hot water and dried the whole thing out with a hair dryer. I just took the kill switch of and notice that the tiny metal contact on the spring inside the red button is bent all askew. I wonder if it wasn't connecting the two medal pads in the kill switch - hence, no connection....

[jotor]

If this bike has been sitting for a long time, I would just get new points and condensers.

I'm with oldbiker on this one--if it ain't broke, don't fix it.  Smooth the points with emery or one of those cool points files still available at Checker Auto.  Then clean them well, using plain white paper as the last step.  Might not be perfect, but it should get you running.  Then you can decide if new points are needed.

Don't think I've had to replace a condenser in several decades of tinking with old bikes.

Easy way to eliminate fuel problem question is to spritz some ether  through each carb.  If there is ANY spark, it'll fire.

[eldar]

If your kill contacts are all bent up, use a couple alligator clips to jumper them and try to start.
It is possible that the connection is not being made.
Another thing you can do is to spray carb cleaner in your carbs and try to start. If it coughs and tries to fire, then you are probably looking at a fuel issue.

[egar]

Good news! I took off the kill button and used a clip to complete the circuit with the two wires in the kill switch, shot some starter fluid in the airbox and the bike actually fired up for about two seconds. I put the tank back on so that I'd have gas, but the bike doesn't seem to want to start. I guess I'lll clean up those points as suggested and give the bike a break tonight. Maybe I flooded it. At least I know it can run! These bikes must sound nice!

[eldar]

When you have the gas on, open 1 bowl screw at a time to see if gas comes out. Just to make ssure you are getting it to the carbs.

[egar]

A new problem. Gas pour out of the rubber hoses at the bottom of the bowls - even when the screws at the bowls are closed. The whole garage reeks of gas and of course, the odor wafted into the house last night. My wife is ready to kick me out of the house. Any suggestions (about the bike problem, not the wife).

[Bob Wessner]

Sounds like floats stuck. Have the carbs been cleaned? If not, this may be your next project. Also check the float height when you finish the carb cleaning.

[SteveD CB500F]

One or more float(s) have jammed. Short term - turn off the petcock!

Lightly tap the carb bodies to free up the floats and they may reseat.

If not, live with turning off the petcock every time you park, or strip and clean the carbs.