The

Unlimited All-Stars

Created to Preserve, Promote and Protect Open Class Kart Racing

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A. Rotary valve or Reed valve Two-Stroke Cycle Engine or Engines, 230 lbs plus one pound for each cc or fraction of a cc. Multiple engines or cylinders are permissible. 210 cc maximum total displacement.

Multiple cylinders mean that a competitor may have more than one engine or a multiple cylinder engine. In this case, as long as the total displacement is under 210cc it's ok.

This picture shows a Komet K-30. It is a very commonly used rotary valve engine. Notice that the carburetor is mounted on the side of the crankcase which is typical of almost all rotary valve engines.

If this particular engine measured out to be 134.2cc the weight would be calculated as follows;

230 lbs (base weight) + 135 (rounded up to next whole cc) = 365 lbs

This picture shows a Rotax, FR125 water cooled reed valve engine.

If this engine measured out to be 123.3 cc the weight would be calculated as follows;

230 lbs (base weight) + 124 (rounded up to next whole cc) = 354 lbs

The Parilla Sudam is one of the most popular reed valve engines used in the UAS. The carburetor is mounted on the front of the crankcase which is very typical of reed valve engines.

If this engine measured out to be 126.7 cc the weight would be calculated as follows;

230 lbs (base weight) + 127 (cc rounded up to next whole number) = 357 lb

Although this Yamaha KT100 started out as a piston valve engine is was modified and fitted with a reed valve so it is required to meet the weight requirements of any other reed valve engine.

If this engine measured out to be 110.4cc the weight would be calculated as follows;

230 lbs (base weight) + 111 (displacement rounded up) = 341 lbs

Most shifter engines are also reed valve engines and they must use the reed valve weight formula. On tracks larger than 1/8 mile the competitor must come up with some sort of device to lock the transmission into one gear.