Yamaha Motorcycle tests
This is the 2010 Yamaha YZ450F the way the MXA test crew raced it. As a rule, we don’t go for exotic or expensive mods, but if push comes to shove, we will seek competent help (no matter how much it costs). Use MXA’s mods as a guide.
The front brake is workmanlike, but the MXA test riders felt that it wasn’t as powerful as it should be. We traded the stock 240mm front rotor for a 270mm Galfer Wave brake rotor kit. The oversized rotor provided progressive stopping power. The complete kit (with pads) retails for $360. For information, go to www.galfer.com.
We don’t like the stock gearing on the 2010 YZ450F. The short powerband of the fuel-injected engine seems to aggravate the gap between second and third gear. Every MXA test rider complained that the bike would fall off the pipe on the second-to-third shift in heavy loam, sand or going up hills. The fix? Gear it down. We ran either 13/49 or 13/50 to help give the bike more oomph out of the corners. The stock rear sprocket is a 48.
This is a stinkbug bike that needs some help in the rear end. Our simple fix was to swap out the stock rising rate linkage for a longer Pro Circuit arm. We used this tactic to great effect on the 2009-10 CRF450 and simply applied it to the 2010 YZ450F. The new link lowers the rear end, which allows a wider range of setup options in terms of fork height, race sag and suspension settings. For more information, go to www.procircuit.com.
Yamaha’s GYTR Power Tuner is a marvelous tool for fine-tuning the power delivery of the 2010 YZ450F. It doesn’t produce more horsepower, but it allows the rider to advance and retard the ignition to produce different styles of power. Additionally, it can change the amount of fuel delivered by plus or minus 21 percent. As a rule, we used the Power Tuner to tame the bark off idle.
When we ordered our 2010 Yamaha YZ450F, we opted for the blue/black plastic. After a short time, we regretted the decision and wished that we had gone with the white plastic, because the dark hues of the blue and black look dingy. To rectify our mistake, we ordered a One Industries YZ450F graphics kit and pre-printed numbers to perk up the dull look. For more information, go to www.oneindustries.com.
Radiator lowering kit:
The radiators on the 2010 YZ450F are 17mm lower than they were in 2009, but with a DR.D radiator lowering kit we could lower them an additional 24mm. This simple $69.95 kit lowers the radiators 41mm over the 2009 radiators. Every test rider could feel an improvement (albeit modest) to the overall feel of the YZ450F in the corners. For more information, go to www.dubachracing.com.
The 2010 YZ450F wiggles at turn-in. It is a minor quibble, but very noticeable. We tried to iron it out with changes to the fork height and triple clamp offset. Although we had decent luck with 20mm offset clamps, the gain was marginal for the cost. In the end, we returned to 22mm Ride Engineering clamps outfitted with a special Honda HPSD steering damper attachment (they also make 20mm clamps with HPSD mounts). Again, the return was minimal, especially given the price of the clamps, adaptor and HPSD damper, but there was a slight improvement. For more information, go to www.ride-engineering.com.
With the sole exception of the Kawasaki KX450F, which doesn’t need any more horsepower, every fuel-injected bike thrives on aftermarket exhaust systems. Why? Because the CRF, RM-Z and YZ-F tend to run flatter on top than comparable carbureted engines. We tested FMF, Yoshimura, Pro Circuit, GYTR, DR.D, Vance & Hines, FMF and Akrapovic systems and felt that every one of them increased over-rev while taming the barky throttle response off idle. Most MXA test riders were split between the more powerful Yoshimura or smoother Akrapovic exhaust.