I recently added the big bore kit to my WR450 because I dropped a valve. It was working great for the first few rides, but today while riding the bike bogged out and stalled. I was climbing a hill and was able to restart it to make it to the top. after several times of the bike bogging out and restarting I was unable to kick start it again. I proceeded to bump start it and successfully got it running in second gear. once I shifted back down to first it bogged out again, no matter how much throttle i gave it. Has anyone had this happen? Also I did ride 50mi yesterday through snow, really high rpm the whole time. I do have the GYTR tunner, replacement throttle pin, FMF Q4-powerbomb, and now the BIG Bore 480.