Using Fuel Additives
I usually don't use it but I want to hear your recommendations.
I ask about this, because I recently remove the headers and muffler from my 912 and found on the exhaust ports of cylinders 1 and 2 some carbon buildup there.
I was checking Sea Foam Fuel Treatment. Its look like a lot of boat people use it on the 2 & 4 cycle engines.
You can read about this product here:
http://www.seafoamsales.com/motor-treatment.html
THX,
Isaac