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TPUSA 994cc Big Bore Kit Available for the Bonneville, Thruxton, Scrambler, America and Speedmaster.

was $2544.55 now $2540.91 inc GST ($2593.62 †)

994 Billet Big Bore Kit


We have Built one of our own bikes using this kit and the Dyno results were unbeleivable HP gain on a 790cc america taking it to 81 RWBHP and a massive torque curve to match.  Made the entire bike a pleasure to ride. We increased the front sprocket by 1 tooth and RPM dropped around 1000 on cruise. With plenty in reserve.

The billet cylinders are carved out of a 65 lb solid block of T-6 aluminum. The cooling area is increased by 40+%. Visually, the cylinders are enlarged to match up perfectly with the cylinder head. The total weight of the new cylinders is only 6 lbs. These are not sleeved, but totally new, and are Nikasil plated to OEM standards. The kit comes complete with 11,5:1 CR forged pistons, rings, custom copper gaskets and lightweight offset wrist pins. The Billet Cylinders are available in 994cc and require machining the cases. The recommended upgrades for the kit are Carrillo rods, a heavy-duty clutch and racing bearings. For further information, please contact the R&D department. Professional installation required. Available for the Bonneville, Thruxton, Scrambler, America and Speedmaster.