Klemm Research Kawasaki Kx285

KLEMM RESEARCH KAWASAKI KX285

GREAT IDEAS SOMETIMES have odd beginnings. Take Klemm Research’s Kawasaki KX285, for example. One day Bill Keefe at Klemm was talking to Kawasaki Team Green Manager Mark Johnson on the phone, discussing the reasons why an American had never won the ISDE. Johnson mentioned that the overall winner of the 1988 event was riding an Öhlins-kitted YZ360—an Open-class enduro bike that was based on a 250 and was easier to ride than a 500cc bike. Right then and there, Keefe decided to build something similar, based on a KX250. Johnson must have smiled.

The Klemm Research World Trophy KX285 kit resulted from that phone conversation. And the finished product, to everyone’s surprise, considerably surpassed all expectations: Compared to a standard 250, the 285 has a wider, smoother, stronger powerband, yet it winds as high as a well-tuned KX250.

Transforming a KX250 into a 285 requires overboring the KX cylinder so it will accept a castiron liner. After the iron liner is installed, it is sized to accept a 72mm piston, with 72.5mm and 73mm pistons also available should they be needed at a later date. The cylinder’s port timing and port shapes are highly modified and the KIPS exhaust valves are hand-ground to match the new cylinder bore and ports.

The KX250 head is machined to accept the bigger piston’s size and squish angle. And the head’s compression volume is carefully adjusted so the 285 will operate on 92-octane pump gasoline.

This extensive reworking of the KX cylinder and head requires five to nine working days; then the cylinder, head, 72mm piston kit and a special copper head gasket are returned to the owner. Assembly instructions and jetting tips for the stock carburetor are included. The stock KX250 pipe performs well with the larger engine and requires no modification.

Klemm also makes kits to provide the KX with more flywheel weight, available in 12, 15 or 20 ounces. The added inertia lessens the likelihood of engine stalling and is invaluable if the bike is used in enduros or for trail riding.

The World Trophy KX285 kit is reasonably priced at $565. Oversize piston kits, complete with rings, pin and clips cost $85. The flywheel kit sells for $74.95. Altogether, the Klemm kits are an effective and affordable way to get a 250 into the Open class.

Klemm Research 139 N. Maple, Unit G Corona, CA 91720 (714)272-8480