I have an 05 YZF 450 here. Seems like it takes 10-15 kicks to start when cold. Also poor throttle response and severe bog when throttle is whacked open suddenly. Other than that bike runs good- great power engine sounds good idle-so-so. I checked the valve clearance and it was within factory specifications. I took the carburetor bowl off and it is immaculate. Bike is low hours-never raced.