01-25-2022, 04:08 PM
I bought a used 2014 CB1100 with 1000 miles on it a month ago (December 2021). The bike is in immaculate condition. Has slight hesitation on acceleration from 1000 to 2000 RPM. At idle the RPM is surging at time from 900 to 1100 RPM. On the freeway it ran perfect. I hooked up a scanner to check for any stored trouble codes, there is none. Live data showed everything normal. I took a wild guess and replaced the IACV, reset the TPS. It started up and ran fine, took it for a 2 miles ride, all good. Next morning, hesitation condition came back, this time worse than before. I removed the spark plugs, #1 plug is black (misfire indication). Did a compression check, all cylinders are reading 175 PSI (WOT).
Put the sparkplugs back in and do a power balance test. #1 cylinder only has 30% drop. Did ohm test on the spark plugs and ignition wires. All read the same. I went ahead and replaced ignition coil #1,4 and all spark plugs. The bike ran perfect now. It is strange that the coil went bad at 1000 miles, and it acted like the IACV not working properly.
Put the sparkplugs back in and do a power balance test. #1 cylinder only has 30% drop. Did ohm test on the spark plugs and ignition wires. All read the same. I went ahead and replaced ignition coil #1,4 and all spark plugs. The bike ran perfect now. It is strange that the coil went bad at 1000 miles, and it acted like the IACV not working properly.