tadhgocuilleain
Registered user
This might be a bit far-fetched but I had a Honda Deauville before the GS and it was known for the front cylinder to run a bit cooler than the rear in them because the rear wasn't getting cooled by air flow. This would result in the front plug being a bit darker. Some people even ran a slightly hotter plug in front to compensate. Have you any gadgets bolted on in front of your right cylinder that could be causing something similar?