Topic: kohler Ch18 build

[FastbackEX]

Anyone have any tips on building a CH18 for a pulling tractor? This is for a stock class so it has to keep the same stroke, single barrel carb, cast flywheel (with no welding or machining. Same rul applies to heads too), and there's a 4000 rpm limit. I'm taking the throttle stop out of the carb, switching to a plastic intake, and maybe an offset flywheel key to start. Any other good ideas?

[Wheelhorseracer]

I would talk to Ryan Kerr at Ryker Racing.. he knows these Kohler Engines VERY well..

You can send a pm to.. Fordman21

[Burton for Certain]

Midwest super cub has everthing you need to make this a great pulling engine. The best kohler pulling twins in the country are build by them. They have tons of parts for stock classes.

[TinRabbit]

1st thing is timing, usually these things can be advanced by 4-6 degree & see good response on the power band. Then you'll have to begin reading plugs after a couple hooks to see if lean (most of the time they r lean)   A good header (both pipes into one collector) will increase torque & the torque band.  Now if you want to do a lil machine work, a 3 angle valve job, maybe  .025" off heads to increase comp ratio & tq but yet will not hurt top end rpm or hp. 
If you're allowed to use the ch750 "closed chamber" heads, those provide the same comp ratio as the 18/20 heads but do flow a bit more IF you can find the early carburated heads, not the new EFI or replacement heads, they r different now   
Watch the depth of the sparkplug electrode in the combustion chamber.
The factory plastic air cleaner assembly is a lil restrictive when you begin to twist over 3500 rpm, run an open airfilter or double up with 2 stacked on the thing.
This should give ya a tid bit to think about & try out. Each engine reacts differently so be patiant & best of luck!