Questions on oil have been popping up quite a bit lately. When you're spending good money on a tuned engine don't skimp on the oil. A $2 bottle of chainsaw oil isn't going to cut it. Sure, chainsaws run WOT for long periods of time but at a much lower rpm. Most of the high end oils out there are good but I wanted to share our experience with Klotz. For some reason it tends to leave a ton of carbon build up. In extreme cases I've seen engine failures. A tuned engine from us for the most part has a .020-.025" squish (piston to combustion chamber) clearance. It doesn't take a whole lot of build up for the carbon to tag the combustion chamber. If this is to happen the carbon can break free from the piston and go into the engine like shrapnel. It's worth every penny to buy a good two cycle oil for your engine. I've posted two pictures below of an engine ran with Klotz and a second with Castor 927. Both engines roughly had about the same amount of run time.