The engine doesn't rev as high as a .15 or 12, but it has a lot more low end torque. It has less HP than my OS 15CV-RX, but I paid a lot more for that engine than I would for the 18. I've heard that it revs at 28000rpm comprared to 36000rpm I get out of my CV-RX. Maybe that's why i'm pulling wheelies. I think the main problem with this engine is that people run it in by what was written in the instructions, I ran it in similar to what they said & the piston & liner died, I believe it needed to be run in a lot richer than what the manual said. I expect that when I get it back & run it in how I usually do it will run fine.