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PREORDER 301cc Complete Big Bore Kit
PREORDER 301cc Complete Big Bore Kit
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FREE shipping on US orders!
We are currently sold out! Kits are in process and preorders will begin shipping in early January.
Originally developed for my racing endeavors on a CBR300R, this 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 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%).
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
- New, OEM Honda cylinder bored to match piston
- Cometic head and base gaskets in custom thickness to optimize quench clearance
- Upgraded Class 10 stud nuts
- Click here for engine break-in guidelines
This kit 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.
Customer Reviews
My journey started with a CRF250L Rally. I was already impressed with the basic Rally, the right size, weight and on/off road handling. But as you all know, it could be better. Suspension was sorted for my weight and then came time for the engine. First, the 286 (CBR300) crank to make it a CRF300L. This was a noticeable increase in flexibility if not outright power. Breathing mods (exhaust and intake) came next followed by the 550PERFORMANCE.COM stage 1.5 ecu.
While all this work increased my enjoyment of the bike and improved its road capabilites, I knew it wasn't quite the best it could be.
Ari Henning's 301cc big bore kit is the icing on the cake.
The stage 3 tune (in conjunction with the 550 Performance ecu) is powerful, flexible and to my way of thinking, has made my CRF301 perfect.
Ari and Maverick worked closely with me to ensure my unique setup (ex CRF250L) was customized correctly and they went out of their way to minimize shipping costs to NZ for my custom parts.
My day job is an Airplane mechanic, I am aware of other kits but wanted to ensure that any mods would be effective and very importantly, reliable. Ari's kit is well thought out using very high quality components with the right balance of performance and reliability. I delayed writing this review to put 1000 miles on the clock to confirm the above and am really pleased to be able to recommend the kit without reservation. Great work Ari,
my Honda is fantastic
I had a lot of questions and Ari answered all questions, very helpful. If you’re on the fence about purchasing this kit, it’s well worth it. You won’t regret it. Definitely makes the bike a lot more fun.
Thanks!
I love the extra power of the 301cc BB kit. This is the way the bike should have come from the factory.It will now do a power wheelie in 3rd gear. The bike is way more responsive thru all gears and will also pull the top gears like it should. I haven't had any issues with the bike in 2000+ miles with the kit installed.
Almost 1k miles on this kit now and I am still blown away with the transformation every time I ride it. This kit completely transformed the bike into a different machine. I did the full stage 4 build with cams, intake, tune, etc and it pulls like a freight train through the full rpm range in every gear. It’ll now rev out to redline in 6th gear no problem. It absolutely rips on the trails and on the road. If you’re on the fence just do it you won’t regret it, I wish I did mine sooner!
Made the little 300cc into an an actual 300 plus some! Improved performance and even sent the piston pre-installed! Thanks for the great kit!
Customer Reviews
My journey started with a CRF250L Rally. I was already impressed with the basic Rally, the right size, weight and on/off road handling. But as you all know, it could be better. Suspension was sorted for my weight and then came time for the engine. First, the 286 (CBR300) crank to make it a CRF300L. This was a noticeable increase in flexibility if not outright power. Breathing mods (exhaust and intake) came next followed by the 550PERFORMANCE.COM stage 1.5 ecu.
While all this work increased my enjoyment of the bike and improved its road capabilites, I knew it wasn't quite the best it could be.
Ari Henning's 301cc big bore kit is the icing on the cake.
The stage 3 tune (in conjunction with the 550 Performance ecu) is powerful, flexible and to my way of thinking, has made my CRF301 perfect.
Ari and Maverick worked closely with me to ensure my unique setup (ex CRF250L) was customized correctly and they went out of their way to minimize shipping costs to NZ for my custom parts.
My day job is an Airplane mechanic, I am aware of other kits but wanted to ensure that any mods would be effective and very importantly, reliable. Ari's kit is well thought out using very high quality components with the right balance of performance and reliability. I delayed writing this review to put 1000 miles on the clock to confirm the above and am really pleased to be able to recommend the kit without reservation. Great work Ari,
my Honda is fantastic
I had a lot of questions and Ari answered all questions, very helpful. If you’re on the fence about purchasing this kit, it’s well worth it. You won’t regret it. Definitely makes the bike a lot more fun.
Thanks!
I love the extra power of the 301cc BB kit. This is the way the bike should have come from the factory.It will now do a power wheelie in 3rd gear. The bike is way more responsive thru all gears and will also pull the top gears like it should. I haven't had any issues with the bike in 2000+ miles with the kit installed.
Almost 1k miles on this kit now and I am still blown away with the transformation every time I ride it. This kit completely transformed the bike into a different machine. I did the full stage 4 build with cams, intake, tune, etc and it pulls like a freight train through the full rpm range in every gear. It’ll now rev out to redline in 6th gear no problem. It absolutely rips on the trails and on the road. If you’re on the fence just do it you won’t regret it, I wish I did mine sooner!
Made the little 300cc into an an actual 300 plus some! Improved performance and even sent the piston pre-installed! Thanks for the great kit!