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**bluewing** · #1 09-29-2007, 08:47 PM,

Have any of you had experience with 1980 CB 750. I am looking at one for a project bike. It looks good, runs but one cylinder has no spark. New tires, new chain, new seat and the paint is good. I can get it for $500. Does anyone have any idea what might cause one cylinder to have no spark? I think when the coil goes there are two cylinders with no spark, not sure. I didn't do a compression test but there seems to be compression in that cylinder when the plug is out and the motor is turning over.

catman · #2 09-30-2007, 05:27 PM,

sparkers or coils and or a bad plug

**bluewing** · #3 09-30-2007, 07:21 PM,

catman Wrote:sparkers or coils and or a bad plug

I think it is coils, I changed the wires from one coil to the other and the dead cylinder changed with it. I will get another one and put it in this week. Thanks catman you were right on.

catman · #4 10-02-2007, 06:48 PM,

I get lucky evry once in a while--try replacing the wires,,,I did on my 83 650 Silverwing and wow what a difference

**bluewing** · #5 10-02-2007, 07:26 PM,

I took the coil out and had it checked, they said that it was no good. I put the new one and I am getting the same thing. I can start the bike and it will run, one and two cylinders will get hot but 3 and 4 stay cold. I tried checking the spark but it is very weak. I guess I will check the pulse coils next.

**bluewing** · #6 10-06-2007, 05:14 PM,

Well, I have the 750 running good now. It turned out to be crossed wires to the sparkers. Looks like someone changes a connector and got their wires crossed. Today I synced the carbs and took it for a run; I forgot how fast those old CB750s are. I am now ready to do the cosmetics on it.

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