Cranking Compression:Effective May 15, 2008, we are changing the maximum cranking compression on a 1200cc unsealed engine to 165 lbs - tested in accordance with the current INEX Rulebook. This cranking compression closely resembles the cranking compression of a stock Yamaha 1200cc engine. If your 1200cc engine pumps more than 165lbs, it is a quick and simple fix by adjusting the cam timing on your slotted cam gear or adjusting the valve shims. Illustrations of the slotted cam gear can be found at www.600racing.com. If you need additional assistance with this procedure, please contact 600 Racing.