301cc Big Bore Piston & Cylinder Set

Awesome upgrade, looking forward to the first test.

I am just now getting into the upgrade, however the kit looks amazing. Everything was very well packaged and was shipped quickly. I am so stoked to feel the bike with the 301cc Big Bore.

It takes a lot of work to get all the body parts off to get to the engine.Just got the new cylinder on and am taking my time as I wait for the reflashed ecu. I will let you know when I get it back together.

How it should be!

If you own a CRF300L and haven't done the 301cc Big Bore Kit, you're seriously leaving power on the table. This kit is the real deal — a race-proven setup with championship wins and a lap record to back it up. The jump to 11.5:1 compression combined with the full Stage 3.0 package transforms what was a capable but underwhelming commuter into an absolute riot to ride. The throttle response is crisp, mid-range torque is dramatically improved, and highway cruising feels effortless in a way it never did stock. What really sets this apart is the attention to detail. Ari pre-gaps the rings, pre-installs them on the piston, and drops the whole assembly into the cylinder for you — so installation is far less intimidating than it sounds. The dyno numbers don't lie either: +25% torque and +34% horsepower with Stage 3.0, and even more if you go with the CNC ported head. For a platform that Honda deliberately detuned, this kit gives you everything Honda left on the table and then some.