I raced this past weekend with the R-Spec and had absolutely no problems besides keeping it fired after the rain passed over and high humidity. I decided not to retune for the humidity and just warmed the engine up to temp and raced a 15min main with no problems. I thought the engine performed flawlessly, even in the straight portion of the track and the temps never went over 226 with the P6 plug and 30% racing fuel. Awesome engine and I would recommend this engine to those that race at club level tracks.