[eugedy3]

Hello
I am new to cycling and to this forum. I have a problem. This bike is a 1999 750 vulcan V twin. I just bought it from a friend, so I do not know anything about it before and month ago except that it was rear ended at a redlight and dropped on it right side. It will start and run fine but I noticed that the pipe on the rear cyclinder was not hot. The front pipe was very hot but the back pipe I could put my hand on. So I put a high energy spark tester on the plug wires one at a time. Each cyclinder has two wires and plugs. The front two both had fire but the back two had no fire. I thought it was odd because the bike runs but I guess it is running on one cyclinder. I worked on a bike years ago that would not run at all if both cyclinders were not firing so I am confused. Any help would be great, Thanks eugedy3.

 

[sfair]

One thing you could do is to remove both spark plug caps for that cylinder and read the resistance between the two caps. Then take the front ones off and do the same. They should be about the same.

If OK, then swap the coils to see if the problem moves to the front cylinder.

Post back with your results.

 

[eugedy3]

Thanks for the help. I switched the coils and the rear one fires and not the front. I guess it must be the coil. Thanks again for the help.

 

[eugedy3]

I do not understand how to check the resistance. What do u set the multi meter on. Do u check the spark plug wires.

 

[sfair]

I do not understand how to check the resistance. What do u set the multi meter on. Do u check the spark plug wires.

The intent of that test was a quick check of plug wires and coil secondary.
Since you moved the coil and the problem moved, you have got the problem nailed.

You would have set the meter on ohms, probably 10x scale and got a resistance reading of the two plug wires and the coil all in one lump. Not knowing the exact resistance values, just comparing with the other coil would have told you if it was in the ballpark.

Post back with how you make out.

 

[eugedy3]

Cool thanks for the help.

 

[sfair]

You are welcome.
Post back if you have any more concerns.

 

[eugedy3]

Thanks for the help sfair. I got a used coil from a motorcycle junk yard and it fixed the problem. I had ridden the bike running on one cyclinder and now that both cyclinders are firing this thing seems like a beast to me. It is only a 750 but seems like a lot power. So I am happy

 

[sfair]

Those particular bikes have a lot of jam for a 750. Have fun.