10BEST MODS FOR THE Where we’d spend our money...if it was your money
HOW TO FIX THE FORKS One of the big disappointments of the 2009 CRF450 setup is the stock fork springs. The 0.46kg/mm springs are too soft. Not just too soft in terms of handling jumps and bumps, but the slight spring rate allows the chassis to shift its weight too far forward. The resulting stinkbug stance causes the chassis to ride low through bumps, dive under braking and oversteer in corners. Step one is to replace the stock fork springs with stiffer 0.48kg/mm springs. Step two is to determine whether you feel there is enough mid-stroke compression damping. If not, you will need to have the forks revalved.
HOW TO FIX THE SHOCK WITH A LINK MXA’s only complaint about the shock was a corollary to the soft forks— in that to get the bike balanced we had to run a lot more race sag than normal (often as much a 120mm). This is not a good idea. Once we stiff- ened the forks by adding 0.48kg/mm springs, we set the sag at 100mm, but the rear of the bike still felt very high. The quickest solution was to install a 146mm Pro Circuit shock linkage. It replaces the stock 144mm linkage. It lowers the rear of the bike by 10mm to help flatten out the bike’s attitude. This was a very good mod, not just for the shock, but for the bike’s handling.
WHAT ABOUT THE SHOCK SPRING? As soft as Honda’s fork springs are, the 5.4kg/mm shock spring is very good for riders over 170 pounds (and it can handle riders up to and over 200 pounds). This is a good spec for a 450cc four-stroke, since most buyers are larger and more mature than the typical 250F owner. Smaller riders will need to switch to a lighter rear spring rate. If you have not changed the fork springs on your CRF450, try setting the race sag at 115mm with the high-speed compression turned two full turns out. These mods aren’t to improve the performance of the shock as much as to try to balance the front and rear of the CRF450.
WHAT IS THE BEST GEARING COMBINATION? Most MXA test riders felt that the stock 13/48 gearing ratio ( 3.692) had problems jumping the gap between second and third. The quick-and-easy fix was to install a 49-tooth rear sprocket to lower the gear ratios to 3.769. This worked well for most Beginner and Novice riders. Pro-level riders felt that the stock gearing was too tall, but that the 13/49 setup was too low for the speed they carried. If you are fast, go to a 14/52 gear combination ( 3.714). It splits the difference. Countershaft sprockets from the old-school CR500 two-stroke will fit on the 2009 CRF450. We had to cut a small por- tion of the swingarm arm buffer pad away to get the big countershaft sprocket on.
HOW HARD IS IT TO REPROGRAM THE FUEL INJECTOR? If you’ve grown up with computers it is no problem to reprogram the Honda ignition. You will need an IBM compatible computer, 12-volt bat- tery and Honda’s $350 PGM-FI tool. To find out how to program your CRF450, turn to page 96. In the process of testing the 2009 CRF450, we reprogrammed the ECU over a dozen times. The Honda tool allows you to advance or retard the ignition and to alter the fuel flow through the injectors. Was it worth the effort? Not really. Although we could shift the powerband around, it was never as significant a change as just adding an exhaust pipe. Most of our attempts hurt more than they helped. In the end, we used the PGM-FI tool to knock the bark off of the first millimeter of throttle twist (where the Honda is so jumpy that it is scary). We retarded the ignition at 5, 10 and 15 percent of throttle from 2500 to 3000 rpm.