The Flex-Hone® for Motorcycles – CRF450X Engine Rebuild

In the history of off-road motorcycles, the 2005 CRF450X was Honda’s answer to the Yamaha 2001 WR450F. Both big-bore bikes captured the hearts and minds of off-road riders, but Honda’s belated entry packed enough power to climb the most challenging hills. Like the R version, the 450X featured Honda’s 4490-cc, liquid-cooled, four stroke-engine and Unicam valve actuation. Instead of using multiple cams, however, the 450X featured a single cam that actuated lightweight titanium intake valves. Inside the bike’s Nikasil-lined cylinders, lightweight pistons with a 12.0:1 compression ratio offered higher RPMs.

Engine Maintenance
According to an off-roader named Ehsan at the South Bay Riders on-line forum, the intake valves on his 2005 Honda CRF450X “got tight as they are known to do” and required a pre-race adjustment. Over the course of a weekend, the biker tore down and rebuilt his entire motorcycle engine. In the process, the biker inspected the pistons and cylinders. Both engine components were worn, but the Nikasil-lined cylinders “looked excellent with a visible crosshatch and no scoring at all.” Nevertheless, Ehsan reported that he “used a ball hone on the cylinder and gave it a nice fresh cross-hatch to help the piston rings seat properly.” Well-done, Eshan!

Ball Hones for Bikes
Engine builders sometimes call our Flex-Hone® tool by other names (including ball hone), but you know you’ve got the best if it says Brush Research Manufacturing (BRM). Since 1958, our California company has provided American-made brushing technology to industries and individuals who need to solve tough surface-finishing problems. So whether you’re an auto parts manufacturer that wants quieter brake rotors or a hobbyist who rebuilds motorcycle engines, you’ll find that the Flex-Hone® is versatile, cost-effective, and easy-to-use.

Cylinder Wall Deglazing
For bike builders like Ehsan, the Flex-Hone® can be  clamped into the chuck of a handheld electric drill. Always use BRM’s flexible honing tool with a lubricant, and for best results choose Flex-Hone® oil. Although our cylinder honing tool can be used in a variety of surface finishing applications, Ehsan’s engine rebuild required cylinder wall deglazing. This promotes lubrication, reduces oil consumption, and helps seat new piston rings. By restoring the cross-hatch pattern that’s worn away over time by the reciprocating movement of the pistons, cylinder wall deglazing helps engine oil to adhere properly.

Motorcycle Talk
Are you a mechanic who rebuilds motorcycle engines? If so, we’d like to hear from you. Honda fans now know how to use the Flex-Hone® with a Honda CRF450X. There’s also a blog entry about the Kawasaki ZRX1200. Will we hear about the Yamaha WR450F next?