Kawasaki KFX 450 R
Over the past year, we've had quite a bit of seat time aboard Kawasaki's latest sport creation, the KFX450R. Other than some cosmetic updates, the KFX has been virtually unchanged since it's 2008 release. And if you're familiar with our past comparisons of the seven 450-class ATVs in early 2008, you're already aware the KFX didn't fare well. In fact, it actually landed near the bottom of our seven sport quad shootout and was in fact last among the Japanese entries. On paper the KFX looks as if it should be near the top of the pile and perhaps first for some applications such as XC-type racing. After all, it possesses some unique and high-performance features such as an aluminum frame, fuel injection, a great handlebar and a whole list of things that somehow just didn't end up panning out on dirt.
Rather than dwelling on the negatives, we've decided to tackle this project by dealing with the issues that can transform it into a very acceptable and competitive off-road quad for a reasonable amount of money. Just to be clear, our objective was not to build an over-the-top MX racer with all of the fancy bells and whistles, but rather to drastically improve its performance for a minimal amount of money. Hopefully, our tinkering might help lead you to buying a Kawasaki or maybe show how you can tune yours up.
In order to get the best bang for our buck, we enlisted the expertise and experience of CT Racing's Allen Knowles on this project. Allen participated in our 2008 shootout and can pick out the flaws of a quad in short order. He and his staff at CT have the capability of dealing with the issues. Even better, CT Racing has the tools at its disposal, including a dyno, flow bench and air-fuel data acquisition equipment to help us develop power and chart the improvements, and anything else that might be required to get this KFX up and rolling like a champ.
Unleashing Power
Diagnosing the first issue was quite easy as the KFX450R is not likely to be king of the hill at your local drag races in stock trim. CT first mounted up one of its complete exhaust systems and sent the KFX directly to the dyno to find out how it performed. The CT Sonic pipe made a significant increase in horsepower, but as we suspected, the KFX with a pipe still fell well below Yamaha's YFZ450 with a pipe or the LT-R with a pipe and cherry bomb, and the Kawi just didn't output the snap and big horsepower we were seeking.
"If you're looking for a dependable...
"If you're looking for a dependable pump gas racer or just a great machine to ride on the weekends, you can't go wrong by emulating what we did on this quad."
The next attempt for creating new horsepower from our KFX was slipping in a Web Camshafts intake cam. This is not the usual process for CT, as it would normally install a piston and both cams at the same time along with a bit of head work, but again we were just looking to do the minimum to get the KFX up to snuff while keeping it running on pump gas. The Web intake cam picked us up a little over 1 hp and widened the power curve with added overrev and an insignificant loss of bottom. Even though adding the cam brought us closer to where we wanted to be, the KFX still did not give us the big horsepower we were seeking.
Before we ever kicked off our KFX project, CT had already been busy dyno testing all of the available intake tracts it could get its hands on. A company by the name of Fuel Customs produced an intake system that CT found to output the best numbers and by a fairly significant margin. The Fuel Customs intake actually would not fit in the stock airbox, so for sand applications where an airbox is not needed, you can run without the airbox. But for our intended off-road usage, we chose Fuel Customs' model with a complete high-flow airbox. This intake system is shipped with a gauze-type high-flow filter and an Outerwears; CT Racing has foam filters available for the Fuel Customs rigs as well. We slipped this on and, to our amazement, the dyno numbers came to life landing it in the 47 hp range.