FMF Builds KX500 in Dungey Replica Frame

Certainly the most interesting bike at the 2 Stroke Motocross Championships was the 500cc concoction from FMF.

It seems that last year the boys at FMF came across a very clean older Kawasaki KX500. I don’t remember the exact year, but it was about a 1992 model. With a little work and clean up, they got the bike running pretty good. On the Dyno it was putting out an amazing 62 horsepower. Considering that this is far more than any contemporary production motocrosser, they decided it was time to remind everyone just how incredible the old big bore two stokes were.

Keep in mind that FMF’s Danny LaPorte raced KX500’s in both Baja and European rallies back in the day. He won the Baja 1000 three times with Ted Hunnicutt, Larry Roeseler and Paul Krause (1988,89,90). Danny told me about his flashbacks when riding the KX500 around the FMF building. ” I almost looped the thing out in parking lot. It just rolled on so hard, I had forgotten. With all this development of four strokes, the fact is that these open class bikes made horsepower that can’t be touched today. We have sort of gone backwards and call it progress”.

FMF’s first idea was to take their new found KX and update it with all the parts that could be found; wheels, brakes, subframe, etc. But then they realized that the overall frame configuration was just too dated. They wanted it to handle and feel like a new bike. The next idea would be to stuff the motor into a newer design frame. They felt it needed to be a steel frame to help keep the vibration of the big 500 motor in check.

So what is the newest design steel frame chassis to be found? The KTM 450sx-f Dungey Replica was the perfect answer. As you can see in the photos, it was not a very difficult proposition to get the motor in. It doesn’t take up any more space than the original four stroke motor. I am curious to know how much work it took to make the cases and swingarm pivot all fit together. There had to be some special machining required. But overall it looks relatively simple and clean. Although I must confess that some of the welds look a little hacked. I am sure the welders out there will cringe, because with just a little more attention to detail, this concoction would be a true piece of artwork.

Motocross Action Magazine is currently testing this bike. They had it out at the MTA 2 Stroke World Championships to race this past weekend. Rider Broc Armbruster finished 19th in the very competitive Open Pro class. It wasn’t the best showing, but I could see the suspension was clearly too soft on the bike.

It does not seem that long ago that the KX500 was practically the only open bike to be found in the desert. When I started racing 15 years ago, the entire open expert line was nothing but green. Given the time period, it was mixed with lots of Kawasaki purple too. I am pretty sure Destry Abbott would have a couple more Hare & Hound championships to his credit if he had been allowed to race his 500 for a few more years.

For as iconic as the 500 Kawasakis were a few years ago, I have only every been one on a couple of times. I was a long time 250 racer and never owned an open class two stroke. But I certainly hope we get the chance to ride this one soon.