I've torn my engine apart twice. Once at 37k and then 5k mile later due to a transmission issue. At 37k I noticed both pistons had quite a lot of carbon build up, however, I figured this was just normal for a bike with 37k. The second tear down, after only 5k on a brand new motor, the amount of carbon build up got me wondering if something is wrong with my set up. In both cases the front cylinder had less then the rear.
The amount of build up after 5k was enough to almost completely cover the top of both pistons and about the thickness of a heavy construction paper.
I run only 93 octane fuel and I'll occasionally add some fuel injection cleaner or an ounce of seafoam.
Any ideas as to why I'm seeing so much carbon build up?