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Get the most from your 2008 and up 450 xc-w or 450 exc and all 2012.5+ KTM 450sxf, xcf, xcf-w and exc-w with Thumper Racings 520 big bore kit built for the XC4 motor. Pull every gear longer and fill in the gappy 5th and 6th. You will be able to pull those sandwashes in 6th. Power is stronger throughout the rpm range but the kit doesn't turn the motor into a beast. You will be able to pull through a corner without down shifting and working the clutch. The 450xc-w/exc big bore kit maintains the stock power feel and delivery with a better bottom end and midrange. Very controlled power and performance. Be sure to note engine year and model when ordering.
Basic Kit includes; You sending in your stock cylinder in to Thumper for rework - our aluminum patent pending "Cool Flow" sleeve installed, nicasil plated and exact honed to a custom 102mm piston, rings, clips, wristpin, topend gaskets and jetting.
Don't want to be down for the time it takes to ship us your cylinder and perform the work?
We have a fully refundable core exchange program. Cylinder core charge is $300 and is fully refunded as long as your core cylinder is returned within 30 days, prorating applies after 30 days.
Please call or email for availability of core cylinders.
PLEASE NOTE: For bikes with ECUs instead of jetting, ECU must be sent into Thumper Racing for reflash. Reflash is $65 extra when purchasing big bore kit.
SHIP YOUR MOTOR TO US OR BRING THE BIKE TO OUR SHOP AND...WE'LL DO EVERYTHING FOR YOU!
Prices do not include shipping.
RAZE 520 Wingman Kit
520 BBK Ring Set
520 XCW/EXC/SXF BBK PISTON