When I decided to go with a big bore on my 2006 Honda CRF450R, I thought I would be one of the few who would really like more boost from a 450R. At nearly 300 pounds I need the extra juice to hang with my riding buddies.  My bike had 175 hours on the engine, and I had installed three pistons, so chances were the cylinder wasn’t perfect any longer. With theCylinder Works kit you get a new cylinder, complete piston kit and all the necessary gaskets along with a boost to 488cc. Like any big-bore kit, the 488 ups the power everywhere in the rpm range.

In fact, though my bike’s crankshaft was doing fine, Cylinder Works recommended I start with a fresh crank before adding more power, so I had a Hot Rods crank installed before the kit went on-just to be safe. See, fixing these four-strokes isn’t off the charts unless you wait for it to come apart. I stick to a rebuild schedule and have gotten well over 300 hours of hard riding before I sell my bikes, and I have never had a serious failure. With that in mind, I pulled the engine down at 50 hours on the kit. The photos are after 50 hours. Both the cylinder and piston looked brand-new. I usually put a piston in every 80 hours, and this kit will easily allow that.

As I expected, the bike has more power everywhere in the rpm range, but I feel it the most down low and in the midrange. Unlike other mods that can make the engine high-strung, the 488 kit made my Honda easier to ride. I do some open desert riding and climb some hills, but my preferred trails are rocky, nasty, slow canyons with stair-steps and waterfall climbs. Even on my low-traction, technical favorite trails the 488 made the bike easy to ride. Sure it climbs better, and some hills that used to be third gear are now fourth, and jumps that I had to rev second on the 450 are easy in third with the 488.

If anything, the power is smoother than stock, and it has less tendency to stall down low. It pulls hard on top and would pull more gearing, but I’m not interested in high-speed riding. The big bore doesn’t vibrate more or boil over any easier than stock, I use the clutch less, and I have no need to scream the engine, so I think valve life (still on stock at 235 hours) will be better than ever. All of my expectations were met and exceeded. The preconception that didn’t hold up was that this kit will only appeal to big guys. It is a hair harder to kick cold, but isn’t any harder to start when hot, it runs smooth and makes power that is easier to ride. Anybody should appreciate this engine.