Originally developed for my racing endeavors on a CBR300R, this piston kit has dozens of race wins, two class championships, and one lap record to its credit. With tens of thousands street and off-road miles logged, this is a proven and reliable setup for improving your CRF's performance, capability, and fun factor.
This big-bore piston kit turns your CRF300L into a true 300 with an additional 14.8cc of displacement and bumps compression from the stock 10.7:1 to 11.5:1. When combined with a high-flow air filter, high flow velocity stack, CBR cams, performance exhaust, and proper tune, you get a massive increase in torque (+25%) and horsepower (+34%). Running our ported head increases performance even more.
Expect faster acceleration, snappier throttle response, and easier highway cruising. See dyno chart and performance comparison below.
This is a complete and comprehensive kit that includes:
Forged 78mm piston, 11.5:1 compression ratio
Piston ring set, properly gapped
Wrist pin and circlips
Cometic head and base gaskets in custom thickness to optimize quench clearance
This kit requires boring your stock cylinder to 0.002"/0.05mm and should be installed by a professional mechanic or someone of similar experience following steps outlined in a service manual. Proper ECU tuning and 91 octane (R+M)/2 (95 RON) gas is required. We offer 550 Performance ECUs and also have PowerVision flashes available.
Warning: This product is for closed-course competition use only and is not intended for street use or use on public lands. This product is not legal for sale or use in California.
