MOTOCROSS ACTION PRODUCT TEST: YOSHIMURA HONDA CRF450 DROP-IN CAM

July 14, 2010
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WHAT IS IT?
An easy-to-install, drop-in, single overhead Honda camshaft for the Honda CRF450.

WHAT’S IT COST? $499.95.

CONTACT? www.yoshimura-rd.com or (800) 634-9166.

WHAT STANDS OUT? Here is a list of things that stand out with Yoshimura’s Cam Shaft kit.

(1) Manufacture. The cam was designed, developed and tested in the USA, but made in Japan. The cam is CNC-machined from billet bar stock and sent to Yoshimura of Japan for special metallurgical treatments. The cam sprockets are also machined from a billet piece. They’re put through Yosh’s ISF (Isotrophic Finishing) process for increased durability and smoother operation. Finally, the parts are machined, inspected, measured and sent back to Yoshimura USA for packaging.

(2) Compatibility. Our test cam was designed for the 2009 CRF450. The stock 2010 CRF450 camshaft is oriented differently where it interfaces with the decompression plunger. If you want to put the Yoshimura cam into a 2010 CRF450 like we did, you must purchase a 2009 plunger (Part Number 06140-MEN-305) for $53.58. If you have a 2009 model, your dealer should have already replaced your stock plunger in accordance with the service update campaign (the tip of some ’09 plungers would break, making the bike very difficult to start).

(3) Design. Yoshimura recognized that Honda’s “Unicam,” single overhead cam is a prime candidate for modification for two major reasons:
      (1) It is easy to remove and install.
      (2) It is a cheaper mod than the dual cams (separate intake and exhaust) on other brands. Yosh targeted mid-and-up performance with increased lift and duration in their cam profile.

(4) Installation. Honda’s single overhead cam is easy to get to. No shims or springs needed. This job can be done by someone with minimal experience.

(5) Dyno result.
Dyno runs on a 2009 CRF450 showed a gain of 1.4 horsepower and 0.6 foot-pounds of torque at peak. Our 2010 Honda CRF450 showed a 1.9 horsepower improvement and 1.6 more foot-pounds of torque at peak. The major gain in power was from 6000 rpm on up.

(6) Track performance. We swapped back and forth with the Yosh cam and stock cam (which proves that it is easy to install). MXA test riders identified more power in the midrange and a racier feel on top. The amount of low-end power was the same, but there was an increased sensation of thrust. It should be noted that while every test rider felt improved power, they didn’t rave about the gains.

WHAT’S THE SQUAWK? A lot of work goes into making a Yoshimura cam, but the price is on the high side?and it is even more expensive for 2010 Honda CRF450 owners who need to buy the 2009 decompression plunger.

The ease of installation of Yoshimura’s cam makes it the perfect mod for CRF450 racers who like to do the work themselves. The power increase is modest, but noticeable.

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