I have an 08 530 EXCr the I have started racing this year. I have the factory exhaust with the inner baffle cut out and the F2 power back mods to the carb and head pipe. I have followed the prescribed jetting settings with the mods as supplied from F2. The bike has a cooling fan and engine ice to keep temps down. The bike runs great without any of the "normal" issues with the FCR carb but after 30 miles of low speed (mostly 1st gear) riding through the trees the bike will begin to stall when the throttle is closed. This stalling wears down the battery first and then my kicking leg follows close behind. If the bike sits for more than 30 minutes it will start and run just fine but I will hour-out the stage in the meantime. Please help a fat old man! Thanks.