I just purchased an new '08 YZ450f. I took it out for it's first run, and I've not experienced any problems with starting te bike hot or cold, and the bike seems to idle well. However, I'm having problems with the bike stalling in 1st gear while holding the clutch lever in. The problem happened several times in a 1 hour period. The bike seems to stall everytime I break to slow down, down shift to first, and before I let the clutch lever out to engage the gears the bike stalls, unless I keep the engine reving very high. This seems very odd, since there are several times when I need to come out of first gear without high revs. for example. Slowed the bike down to approach a small hill that I've not been down. Down shifted to first, got to the top of the hill, while I was still holding the clutch lever the bike stalls. Any ideas?