TB KLX140 Big Bore Kit – 170ccThis Big Bore Performance Kit includes the following Aluminum cylinder with steel sleeve (63mm) High compression 63mm piston with rings, pin, & clips Head gasket kit Note: 2025+ KLX140s require case boring to fit. Our cylinder skirt is 65.95mm 2025 cases are only 65.4mm wide. This affordable 170cc Big Bore Kit will make your KLX140 a lot more fun to ride by adding some much needed power. This kit does not require boring of the case – simply bolt on and go!!There are no installation instructions, but if you can replace your piston, you can install this kit. If you don’t have any experience working on your engine, we highly recommend having a professional technician install this kit or, at a minimum, purchasing the shop manual for your bike available from your local Kawasaki dealer. The parts are installed in the same manner as the OEM parts.