ok... lets try this again
Try going down 1 tooth on your CS sprocket, so if you have a 13, get a 12, if thats helps, but not enough go up a tooth or 2 on the rear sprocket, and you should be set! 
KTM 300 E/XC
Engine Type: Liquid-cooled 2 stroke
Displacement: 297cc
Bore/Stroke: 72 X 73mm
Transmission: Five-speed WR
Gearing: 14/52
Chain: Regina o-ring
Tank Capacity: 13 liters (3.4 gal.)
Carburetion: Keihin 38 PWK D-slide
Ignition: SEM CDI 130w lighting
Forks: Marzocchi Magnum 45
Suspension Travel: 300mm
Front Brake: Hydraulic disc
Front Tire: Michelin MP11 90/90X21
Rear Suspension: Ohlins Type 3A
Suspension Travel: 345mm
Rear Brake: Hydraulic disc
Rear Tire: Michelin MP11 130/80X18
Seat Height: 945mm
Wheelbase: 1468mm
Ground Clearance: 386mm
Claimed Dry Weight: 229 lbs.
Suggested Retail Price: $5698
There are the specs for your bike, so get a 13t CS sprocket, and you can go up on the rear still