Practically all four stoke engines used in kart racing are a "wasted spark" ignition. They spark once for every turn of the crankshaft. 
Once on the ignition stroke at TDC and again at TDC on the exhaust.
This is a source of confusion for many when they are setting their MyChron datalogger 

This Applies to a range of motors including:

Honda GX series: GXH50, GX120, GX160, GX200, GX390 and others

Briggs and Stratton:  Flathead. Animal/Intek based motors including the LO206, and World Formula.

Clone\Chonda and Predators

This means that the RPM setting on your MyChron should be set the same for 4cycle and 2cycle motors. A tell tale sign of this being incorrect is that your RPM reading is half what you would expect it to be. If you normally see 6000RPM and your reading is 3000, then this is likely the fix.

Enter your Mychron4's menu and set the RPM Factor to x1 as illustrated below.




Thats it! Happy revving!