Thats a KLX not a KDX. My brother has a ex Team Green KLX300 with a 331 BB built by Stroker Racing, now 4 Stroke Works. It has a extended swingarm, modified shock with KX internals, KX500 forks. It was pretty tricked out and ridden by a local Team Green rider in enduros. Theres all kinds of stuff for these bikes, 365 BB kits, E start kits etc. The late model KLX250 dualsports are very similar. Ive seen KLXs with 99-02 KX tanks and plastics on them. Yours has a aftermarket tank on it. They make great little woods bikes when built right and can humble the expensive euro trash in the right conditions!