By John Basher

MXA tests a lot of Pro racer bikes. Every machine has unique characteristics that offset it from every other bike. That’s the allure of riding such prized steeds. Taking a few laps on, say, James Stewart’s old Kawasaki SR450 provides a glimpse into how Bubba rides and what he likes in terms of setup. In general, it’s not otherwise enjoyable riding a Pro’s bike. Imagine driving a car with the steering wheel in the passenger’s seat and the gas pedal on the left. Comfort goes out the proverbial window.

The MXA wrecking crew has known Sean Collier for a long time. We’re fans of the kid from Santa Clarita, California. He has always been a natural talent. Never mind that he was a bit wayward in his pursuit of a lucrative Pro career–something that could have easily been his. The kid didn’t care for Supercross and he, like many, got hurt at the worst possible times. Then again, when is it ever convenient to suffer injury? Since retiring from full-time racing and settling down with a wife and kids, Collier continues to race special events like the MTA World-Two Stroke Championship and the Dubya World Vet. In fact, at 2015 Glen Helen National Sean decided to race the AMA National and also compete in the sideshow FMF Two-Stroke Invitational. He won the two-stroke race going away on his father’s 1997 Kawasaki KX500.

Last week I wrote about Jeff Moffet’s one-off KTM 550SX Factory Edition two-stroke (if you didn’t read about it, click here). This week I’d like to talk about Collier’s modified KX500. It’s another unique story about what can be accomplished with ample amounts of time, money and testing. And, believe it or not, you can build your own Sean Collier KX500 replica if you so dare.

“COLLIER’S KX500 SURPASSED 66 HORSEPOWER ON THE DYNO, WITH 45 FOOT-POUNDS OF TORQUE. IF YOU THINK THAT’S NOT ENOUGH POWER, THEN YOU’RE EITHER DELUSIONAL OR NOT FOLLOWING THE RIGHT MOTORSPORT. IF SO, MOVE ON.”

Luc Caouette, or “Frenchie” as he’s generally known as, was responsible for resurrecting Collier’s KX500. When Frenchie took control of things he discovered the bike was a pile of junk. The thing had been neglected for 17 years. He did what any competent mechanic would do, which was strip the bike down to the frame and start the rebuilding process. Frenchie painstakingly went through every single bolt to ensure that everything would hold together once Sean lined up to the gate. Below is a breakdown of what went into the build:

1. Engine. Caouette rebuilt the crank and re-matched the cases, which was necessary since Kawasaki no longer sold the crankcase. He also replaced the main bearing, ported the cylinder, installed a larger carburetor and boosted compression. VP C-12 race fuel was vital. FMF crafted a specially made pipe and sent over a Titanium Powercore 2.1 silencer. Collier’s KX500 surpassed 66 horsepower on the dyno, with 45 foot-pounds of torque. If you think that’s not enough power, then you’re either delusional or not following the right motorsport. If so, move on.

2. Suspension. As previously mentioned, there’s always one area on every Pro’s bike that stands out. Collier’s suspension package got the nod on this bike test. Why? Frenchie retrofit a 2015 KX450F front end with Showa TAC air forks onto the KX500. Believe it or not, the transfer was a breeze by fabrication standards. Since the fork stanchion diameters were the same, all Frenchie had to do was slide out the old forks and put into the TAC forks. As a result, Collier was able to run a modern front brake setup with a Moto-Stuff 280mm rotor. Graeme Brough serviced the suspension.

3. Setup. It’s important to maintain creature comforts, especially when working with a Pro rider. Sean Collier requested that a Scotts Performance steering damper be installed. Done. He also asked Frenchie to grind the stock footpegs until they were razor-sharp meat cleavers, because apparently Sean’s feet had a tendency to slip off the pegs otherwise. Done.   

4. Accessories. Collier’s KX500 wasn’t exactly a beauty queen. That’s because aftermarket companies don’t have a vested interest in making products for a bike that was discontinued over a decade ago. Still, there were some mods made to Sean’s steed, like a Cycra Racing front fender, fork guards, hand guards and front number plate; Boyesen ignition cover; Takasago Excel rims; Renthal bars, grips, chain and sprockets; Dunlop tires; and N-Style graphics.

Was Sean Collier’s 1997 Kawasaki KX500 any good? It all depends on your willingness to twist the throttle. Pro-level testers, like Daryl Ecklund, didn’t want to pull into the pits. Others couldn’t come to terms with the light-switch throttle response. Ultimately the best way to ride a 500cc two-stroke, modified or stock, is to ride a gear high and hang on for dear life.

Do you want to know more about Sean Collier’s KX500? Take a look at the video below. We also test rode his tricked-out AMA National Kawasaki KX450F in the video. If you want the full scoop, consult the September 2015 issue of MXA.

SEAN COLLIER’S KX500 VS. KX450F