I FIND I GET ALOT OF VALVE CLACK FOR MINE.I AM ALSO A LITTLE DISSATISFIED WITH MY BIKE AS I BOUGHT IT WITH 4 CLICKS ON IT,FALLOWED ALL MAINTAINCE RECOMENDATIONS AND HAD TO HAVE THE ENGINE COMPLETELY REBUILD AFTER MY SECOND SEASON.I AM WOUNDERING IF ANYONE ELSE HAS HAD ENGINE PROBLEMS WITH THIS MODEL?