Cylinder Works 270cc kit

My Review of the Cylinder Works 270 kit.


I have found in my 15 years of racing motocross, that OEM products work well more times than not, and some aftermarket parts do little to improve the feeling or reaction of a dirt bike. When I set out to change the feel, and the power of my CRF250R, I was greeted by something I had never expected: The Cylinder Works 270cc big bore kit. I read all of the reviews, saw the break downs, and felt the kit was built for me. A 30 year old B rider that loves to ride a small bike, and ring it for all it's worth. The Honda fit me, just like Hondas have always fit me, but the CRF was missing something, and I wasn't sure what it was.[/b]


Here, you can see the Cylinder Works 270cc kit is more than just a cylinder and piston, it's an entire assembly!


The Cylinder works kit uses their own proprietary cylinder cast right here in the USA, with a production built forged Vertex piston that has a coating on the skirted sides. This isn't just a big bore kit, this is an engine kit. Included are all the other high quality parts you'd buy when assembling your own build; full Cometic gasket kit, new wrist pin with cir-clips, and the previously mentioned 13.2:1 forged Vertex piston.


Assembly was a snap, I pulled apart my 10 hour old CRF down to the bottom end only, and started measuring and assembling. Everything lined up, and came together well, even the end gap on the rings was preset spot on. The attention to detail remind me of the works machines I see in the magazines, small things like the machine work on the piston for the cir-clip on the piston to be installed were perfectly placed, to the beautiful cross hatch in the cylinder done by Millennium Technologies in Wisconsin. Altogether, assembly took an easy 3 hours from start to finish.

My ride review

You would assume, just adding 20cc's wouldn't be a massive change, but it is. The bike roared on the bottom, becoming snappier and mean, where the pillow feeling on the top was all but gone. The gains can't be pinpointed to anyone area, it's the entire power band. My over rev increased, as did the top end charge the CRF never had much of in the first place in the factory configuration. The reviews and dyno charts were right! My CRF was transformed, from a mellow 250, to a pure fire breathing dragon. In sections I'd need to bump down to 2nd gear to get off the corner fast, I could keep the bike in 3rd and pull harder. Certain jumps that would take everything both I and the CRF had to get over, with the 270cc kit, these were no longer an issue. It wasn't just the power that changed, it was the reaction. The power was more, but also easier to manage, the power band wasn't snappy in any one area like previously, but actually linear and smooth. The need to use the clutch faded, as every time the throttle was twisted, the bike would respond immediately without compromise.


Over all, I am very impressed with the Cylinder Works 270 kit. The machine work, attention to detail, and the final product have impressed me beyond expectation. Now with 10 hours on the machine, I couldn't be any happier with the changes made. I've gone on to add a Hotcams Stage 2 camshaft, and will have a review detailing that soon!

The Bike:
• 2012 Honda CRF250R
• VP Racing U4.4 fuel
• Sisneros Speedworks ECU flash
• DrD full system
• No Toil High Flow kit
• DID ERT2 Chain
• Renthal ultra light 13T Countershaft sprocket
• Sunstar Works-Z 52T rear sprocket
• MX51FE front tire/MX51 rear tire