The reason I was asking was about carbon build up,I guess there is a reason they tell us to run synthetic,It seems very difficult where I live to find a fully synth 2 stroke oil,so I was running with a marine outboard 2 stroke oil (I procured about a case of it from uncle joes garage) after a few weeks I was running like Sh###,yesterday I checked the exhaust and it looked like a coal mine in there,I cleaned it as best I could without making a project of it then rode about 5 miles with good improvement,I stopped at the parts store and bought this seafoam on reccomend,It says about 1 oz per gal more to clean less to maintain so I put 3 capfuls in a tank about 2/3 full,mabey its all in my head but within a mile I noticed a positive difference,I have several hills I use for testing,I am about 230# and if the bike gets up the hill fine I know its ok.LOL I did notice better preformance before I became unemployed and gained 20#,In short I think the seafoam was a good idea,however I will measure more accurate next fill......Thanx guys