This weekend I put my first 45 miles on my new 2003 WR450. I rode dirt roads, pastures, a short woods trail, and some tight woods stuff. I shortened the throttle stop screw and removed the two-hole air baffle at the filter after about 3 miles of playing. This bike is awesome. I can hardly believe the power, especially after 1/2 throttle. I have an appointment in about a week to get the Woodruff key issue checked out per the -007 technical bulletin, although I had no problems whatsoever so far. By the way, starting is easy with or without the starter. Now for my problems(or questions). During the tight woods stuff or when I rode barely above idle in 1st or 2nd gear, my radiator overheated three different times. The 1st time I lost all that was in my overflow jug. The other two times I stopped the bike to check it and the coolant was churning and gurgling. This seems like too much heat, even for low RPM riding or short idling. Any similar experience? Also, after the first overheating, I had trouble with my shifter. It doesn't spring back when downshifting. I often had to pull it up a little with my foot. Please let me know if any of you have had any similar experiences or have any suggestions.