There have been very few big bore kits that I’ve preferred over the stock displacement, so I was surprised on top of impressed when the Cylinder Works 270cc kit turned the smooth and tame 2011 CRF250R into a still-smooth and incredibly strong racer.Most big bore kits for 250Fs that I’ve ridden added a chuggy feel to the rev that took away what responsive feeling the stock engine had and steered the power delivery toward the XR400 side of the motocross track fence (which is outside the MX track and into the trails leisurely). But the $599.95 Cylider Works kit worked magic. If you listen to the Cylinder Works rep, he’ll tell you that all the new fuel injected 250Fs wake up with the additional cubic centimeters, and he is absolutely right in the case of the Honda.We met out at Racetown last week, where the track was ripped deep and soft and perfect for stealing power from small-displacement bikes. We pitted the Cylinder Works bike, which was bone stock except for the addition of the 270cc kit against my 2011 long haul CRF, which has a MotoTassinari Air4orce intake (which helps a lot with response and a power boost) and a Hinson slipper clutch as the only performance mods. Ridden back to back, the 270cc bike was a completely different world. On straights the 270 revved just as quickly as the lightly-modified 250cc bike, but still had some throttle left if I needed to lighten or even lift the front end over some soft sections. The power felt better everywhere, and was especially meaty in the mid range when charging out of corners. With the stock exhaust the bike even sounded much stronger, something people trackside noticed, but the sound was not obnoxious, just impressive. If you ever saw Villopoto race his factory 250F… it sounded kinda like that.
The engine package felt like a smaller version of what the KTM350 aimed for – a lightweight and nimble bike with that extra bark to get over big obstacles and add some fun. I see this 270cc bike as a step toward a 250cc two-stroke – the additional power gives it that feeling of having power on tap at nearly any time, and brings the throttle more into play as a way to control the bike.Even though the bike was decked out with my race number and I had in my head that it was my personal race bike, I let fast-guy staffer Chris Green and faster-guy head honcho Jimmy Lewis take it, and my ‘stocker,’ for a spin. Both were equally impressed with the engine and its ability to rev. Lewis was coming off a 450 that day and was surprised how much drive the 270 gave him off jump faces. Both fast guys agreed the motor was willing to rev and didn’t fall flat like a punched out 250 can.
This was just one day at one track, and we’re going to do more testing with this kit on this bike as well as on some other bikes (even one with, gasp – a carburetor!), so watch the pages of Dirt Rider, and don’t be surprised when this kit finds it’s way onto my Long Haul CRF250R! I mean CRF270R!www.cylinder-works.com