ORIGINAL: Snipin_Willy
I've used the .12 CV and .15 cv-rx and my latest motor is an '05 Fantom FR12. The engine is way faster than either of the OS engines I've used, but it was also harder to break in.
How long have you had it and how much fuel do you have through it? Does it hold a good tune? I have a OS .15 CV-RX in my MT1 Racer with about 3 or 4 gallons through it and it still sreams. Runs as good as the day I break it in.