Topic: Points wiring

[Slayer]

I am having a hell of a time getting this 77 750F started. After doing a valve adjustment and compression test I tested spark and I was not getting anything out of 1-4 side. I had voltage on the black and white wire before it splits for the two coils and no voltage at the blue wire that attaches to the points so I learned how to solder and soldered both wire connections that lead to the points. I now have voltage at the point end of the blue wire. When I connect the wire to the points it shorts out so that is where the problem is. I thought I might have the wire order wrong on the points so I checked on the forum and connected it like their successful order and still nothing. I had it exactly the same as the yellow and that side was working good so I am assuming that is not the problem. I rechecked the gap on the blue side and it is .3mm, same as yellow. I am now back to totally confused... please help 


Blue=not working, yellow=working

[Lumbee]

swap the wires (yellow/blue) and see if you get spart on 1/4. I like to take screwdriver and manually open the points and check for spark that way. If its sparking on 1/4, and not on 2/3, then its probably the condenser.

[MJL]

swap the wires (yellow/blue) and see if you get spart on 1/4. I like to take screwdriver and manually open the points and check for spark that way. If its sparking on 1/4, and not on 2/3, then its probably the condenser.

I did that one night, was opening the points with a screwdriver and got the surprise of my life, the motor started. One of the cylinders must have been on compression just right and I lit the fires.    I was sparking it rapidly and I think that helped it, it took awhile for it to go.

It was kinda weird I thought that I could hear either the plugs sparking or the coils discharging, I didn't know which.

[MJL]

Actually, leave the yellow and blue wires alone and swap the green condenser wires, if it doesn't change anything then it's the points.

[bryanj]

It might be my eyes but the bolt through the blue does not look in the centre of the hole, there shold be a shaped insulator ,have you left that out?

[KingCustomCycles.com]

Points are simply switches on the ground side of the circuit.  Closed points build "power" in the coils and open points collapse the "power" and send a spark.  It is perfectly normal to have voltage at the points when they are closed, they are grounding the circuit.  When they are open, they will not complete the ground.  It is common to have a failed condensor on these that causes all sorts of problems also.  Failed closed and they short, failed open and you get sparking at the points and erratic firing.  I hope this helps.

[TwoTired]

It might be my eyes but the bolt through the blue does not look in the centre of the hole, there shold be a shaped insulator ,have you left that out?

That's a good eye there Bryan.  That wire mount screw should go through the center of the hole and NOt touch the point mount body.

It is perfectly normal to have voltage at the points when they are closed, they are grounding the circuit.  .

That's just not right.

If the points are working, the voltage across the point contacts drops to zero when closed, and they will pass CURRENT.  Open the points and current drops to zero and voltage rises to that which is applied.

[MJL]

I used the term "power" to simplify the concept and to help with understanding.  A teaching skill lost on you most of the time as you try to impress with the depth and breadth of YOUR knowledge at the expense of actually helping someone.  It is a common problem of the insecure and those that worship their own intellect at the expense of any real truth.  I am now, officially, back. :-)

"You meet the nicest people on a Honda"

[Slayer]

I switched the blue and the yellow wires for a test and yes, there is no shaped insulator. It blows me away that you caught that! I took the old one from the damaged point and replaced. It is still only sparking on the 2-3 side so it must either be points or condensers. I tried swapping green condenser wires but they did not reach. Unknown to me I left the ignition on in the excitement while I searched for a condenser test thread. The Clymer has a few paragraphs on it but it was a bit confusing. I did not find anything so I figured I would remove the condensers and physically swap them. My battery is now dead so I am going to get it charged up and try it. Any other simplified condenser tests would be great.  

[Slayer]

I thought I had a wiring short so I soldered the connections wire by wire just to make sure they are solid until I reached voltage at the end of the blue wire. I attached it to the points and it shorted out. I recharged the battery and attached the known good condenser to the non working side (1-4) and it still did not work. That narrowed it down to the points. Timed correctly, with voltage, a good condenser and good ground. I replaced the old points with new since there might be some sort of insulation issues. Bingo! Thanks guys! Points work now, but to find out if the bike ran follow this link: http://forums.sohc4.net/index.php?topic=55401.25