Inasmuch as I only use Chevron 92 octane with techron and pure 93 octane without corn I don't worry much about carbon.
Marty - in the western Oregon mountains.'06RT, (gone '04RT, '86 Venture Royal, '81 Yamaha Virago920, '82Suzuki GS1100GK, '76 Suzuki GT750, Triumph 750 Bonneville, BSA Road Rocket 650, 61" Harley knucklehead)
To quote someone else "without photos it didn't happen". Marvel Mystery Oil is great stuff, we used it much
back in the stone age of inaccurate fueling and dirty fuel. Digital engine management controls, cleaner fuels and better oils have all led to carbon build up being a "non issue" for the most part. Of course one might suspect adding oil to your fuel might actually induce some carbon build up eh? I'd further wonder what effect it might have on catalytic converters.
Will Stagg Central Coast of Commiefornia
Yamaha TW200 adventure bikes (multiple offender)
The ones that consume larger amounts of oil have higher buildup.
My own has very little carbon (borescope inspection) with a consumption rate of 100ml/1000km.
The real oil slurpers have lots of buildup.
It's all about the details.
MMO, Rislone, CD2 Detergent and other solvents have their place to address specific problems if and only if those problems are present, and real. Keeping a K bike sprag clutch clean is a good example.
But the indiscriminant use of any such solvent just because can have unintended consequences, such as reducing the effectiveness of ring sealing, for example.
My preference for dealing with normal carbon buildup is to run the bike hard and long going down the highway. Or, a bit of Techron Fuel System Cleaner in the fuel every 12K miles or so will address carbon in the top end without putting a detergent everywhere the oil goes.
I recommend you change the oil after dosing the engine with a full tank of fuel with Techron. Thus I time it to be just before a major service at 12K intervals.
Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
I agree with you Paul. I do pretty much the same thing with Techron only at 6K oil change. No doubt run 'em hard is the best way to clean up the top end. Somewhere I read a piece about Marvel Mystery Oil and its tendency to foam because of the very high detergent properties. I say just do regular oil/filter changes with good quality oils and go for a ride and never mind the additives. I use pure gas most of the time but will fill with ethanol on occasion when finding pure gas is not super easy. When I do fill with ethanol I use regular grade just because I think it less likely to get old gas than with premium ethanol.
I broke my '94 RSL in fast and hard. Even took it to Big Twin BMW at Boise for 3 pulls to the rev limiter on the dyno when it only had 500 miles on the odometer. She made good power right to the limiter so I was very pleased and I was amazed by how flat the torque curve was and all this on otc Valvoline 20/50 VR-1 racing oil with high ZDDP content.
I will say though, that up here in Wisconsin, I make it a point of not using ethanol blended fuels whenever possible, and I never store the bike unused for any length of time if I do have to fill it with E10.