Dusty1,
The first thing you might want to check is the throttle cable adjustment. Most of the dealers never do. Virtually every one I have owned or serviced does not open fully. Its a quick easy adjustment at the thumb lever housing. Loosen the lock nut and take up the slack in the cable and you should expect some improvement. 40 mph is not a normal top speed for these bikes. I ride with 4 other 450s. They are all set up the same and are nearly identical in top speed at about 49! Good luck!