Loss of one cylinder
TrapperAH1G:
Riding on twisties and noticed bike wasn't running right, sluggish. Pulled over and in checking it out, found that pulling the plug wire on the left front cylinder doesn't change how it runs. Definite change in idle if I remove any of the other five wires. From this, I assume the coil should be ok since the second plug wire has spark. Changed plug, no joy. Plug wire? How hard is it to remove ends and replace just the wire?
Thanks for your thoughts, wisdom.
Jims99:
Pull the plug, stick it back on the wire, lay it against metal and start the bike. You will be able to if it’s firing or not. The area can be changed but not sure how difficult that is. Butch Fowler and wood butcher make up coil packs with new wires even in different colors. May also be a clogged float (sticking) not getting fuel. You can’t try running a strong dose of B-12 or Techron to try clear it out.
98valk:
Quote from: TrapperAH1G on April 03, 2025, 11:34:17 PM
Riding on twisties and noticed bike wasn't running right, sluggish. Pulled over and in checking it out, found that pulling the plug wire on the left front cylinder doesn't change how it runs. Definite change in idle if I remove any of the other five wires. From this, I assume the coil should be ok since the second plug wire has spark. Changed plug, no joy. Plug wire? How hard is it to remove ends and replace just the wire?
Thanks for your thoughts, wisdom.
the wire is attached to the coil with a plastic compression tube fitting like this but not brass
https://automation-renew.blogspot.com/2013/02/compression-tube-fittings.html
the wires are stranded cooper, and there is a metal spike inside the coil end that the cable is pushed onto.
the plug end actually has a removable resistor. there have been some reported cases of one failing.
from some research yrs ago the carburetor Honda engines all had the same coil/wire setup.
do an ohm check on the plug, it might be bad.
A nice performance mod I did yrs ago and which I need to reinstall this yr is re-installing the hotter firing blackbird coils.
h13man:
Well I have fouled two stock NGK's on my bike at two different times both times the plugs were just over 10,000 mi. on two different cylinders.
If you look in the OEM manual, 8,000 mi. change intervals. After the last time I installed NGK Iridium as they really perform great cold starting to the point I only use the "enrichner" at spring roll out only. I have 12,000 on them at this time. Basically getting all I can out of them as I keep a spare in the tool kit.
BTW, there a PDF floating around here somewhere showing how to rebuild the wires using stock components. I used the following:
https://www.speedwaymotors.com/Red-7mm-Solid-Core-Spark-Plug-Wire-20-Ft-,5117.html?sku=91064011&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=Cj0KCQiAhs79BRD0ARIsAC6XpaVH24FToirTU7ukZyHMQuJiYQA7Vg0Z1KagAcFw2BPccdhc5HUqLBkaAkvkEALw_wcB
John Schmidt:
You said no spark on #2(left front), do you have spark on #1...right front? Both fired by the same coil, the one near the front tucked under the tank on the left. I'd just raise the tank enough to get at the wires and check for bad/loose connections for the plug wires. Then check continuity on the #2 wire, you may have a bad resistor which is inside the rubber plug cover.
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