Post by xwindpilot on Oct 12, 2016 0:40:57 GMT -6
Hello world!
I am new to this forum and have been lurking through threads trying to get a handle on my ignition issue. I am an aircraft mechanic and would consider myself as mechanically savvy but totally new to working on bikes.
I have a 1986 454 that I bought from a good friend of mine recently. He did some work on it including rejetted carbs, new handlebars and seat. I have owned the bike for about a week and rode it 250 miles with no issues. Until now!
In a nutshell:
- Left plug wont fire
- Battery good
- Starter good (engine cranks)
- Both plugs new
- Both leads and boots swapped and issue stay on left
- Resistance reading on primary and secondary coils are in spec
The bike started having lurchy acceleration followed by afterfires from the left pipe and difficulty idling. The left exhaust smelled rich so I figured the carb needed adjustment. Before diving into that I bought new plugs figuring the rich mixture had fouled the left plug. When I pulled the left plug to change it I found it to be in good condition. Next I removed both plugs and cranked the engine to make sure they would fire. Right side has a good spark, left side no spark. I swapped plugs left to right and confirmed that I still only had spark on the right (with the left plug installed in RH position). I tried two new plugs and again only sparking on the right. Then I swapped plug boots and had the same issue so I swapped leads and the issue remained. Next logical answer was a bad coil on the left side so tonight I busted out the haynes manual and tested primary and secondary coil resistance on both sides (I did both sides as a comparison since I knew RH was working) and found both coils to be smack in the middle of manufacturers recommendations.
Now it seems I am down to the pickup coil (which I have not tested) IC igniter box (which I cannot find specs to test) or the wiring somewhere in between (which... ugh)
Please let me know if I am missing anything obvious. Also the battery and starter are good and I would assume since I can get the right side to fire that all safety switches are good too (let me know if that is a bad assumption to make).
Some quick questions:
- If both primary and secondary coils are within spec does that rule out an issue with the pickup coil, or is the pickup coil wired in such a way that it could only be providing power to one of the primary coils?
- Are there any known "gremlins" in the electrical system that I should start with?
- Is there a way to test the IC box?
- Has anyone dealt with a similar issue?
Any help, including wiring diagrams, would be greatly appreciated. Thanks in advance!
- James
I am new to this forum and have been lurking through threads trying to get a handle on my ignition issue. I am an aircraft mechanic and would consider myself as mechanically savvy but totally new to working on bikes.
I have a 1986 454 that I bought from a good friend of mine recently. He did some work on it including rejetted carbs, new handlebars and seat. I have owned the bike for about a week and rode it 250 miles with no issues. Until now!
In a nutshell:
- Left plug wont fire
- Battery good
- Starter good (engine cranks)
- Both plugs new
- Both leads and boots swapped and issue stay on left
- Resistance reading on primary and secondary coils are in spec
The bike started having lurchy acceleration followed by afterfires from the left pipe and difficulty idling. The left exhaust smelled rich so I figured the carb needed adjustment. Before diving into that I bought new plugs figuring the rich mixture had fouled the left plug. When I pulled the left plug to change it I found it to be in good condition. Next I removed both plugs and cranked the engine to make sure they would fire. Right side has a good spark, left side no spark. I swapped plugs left to right and confirmed that I still only had spark on the right (with the left plug installed in RH position). I tried two new plugs and again only sparking on the right. Then I swapped plug boots and had the same issue so I swapped leads and the issue remained. Next logical answer was a bad coil on the left side so tonight I busted out the haynes manual and tested primary and secondary coil resistance on both sides (I did both sides as a comparison since I knew RH was working) and found both coils to be smack in the middle of manufacturers recommendations.
Now it seems I am down to the pickup coil (which I have not tested) IC igniter box (which I cannot find specs to test) or the wiring somewhere in between (which... ugh)
Please let me know if I am missing anything obvious. Also the battery and starter are good and I would assume since I can get the right side to fire that all safety switches are good too (let me know if that is a bad assumption to make).
Some quick questions:
- If both primary and secondary coils are within spec does that rule out an issue with the pickup coil, or is the pickup coil wired in such a way that it could only be providing power to one of the primary coils?
- Are there any known "gremlins" in the electrical system that I should start with?
- Is there a way to test the IC box?
- Has anyone dealt with a similar issue?
Any help, including wiring diagrams, would be greatly appreciated. Thanks in advance!
- James
