12 HP LIGHT MODIFIED PRO TIRES
-
Single cylinder 12 HP engines and under.
-
4,000 RPM limit, regardless of flywheel type.
-
1,050 pounds weight limit.
-
All tractors must be stock in appearance. Officials must approve alterations.
-
All engines must have OEM dimensions and specifications noted in these rules.
-
Stock Block - can be sleeved - must maintain stock bore no more than .030 over.
-
Stock head.
-
Stock crankshaft stroke must be maintained. Steel cranks allowed.
-
Stock valves required.
-
After market camshafts permitted..330" max lift at zero lash.
-
Head gasket must be a composition gasket – no copper gaskets.
-
Stock carburetor required – venturi to be no more than 1.200" diameter.
-
Choke can be removed.
-
No intake standoffs allowed – 1 inch spacer maximum.
-
No porting or polishing of intake and exhaust areas allowed. Deburring in these areas is permitted.
-
Exhaust for all tractors must discharge upwards or towards the rear of the tractor - not out to the side, unless running stock muffler (discretion of officials).
-
All clutch assemblies must be covered 180 degrees on topside. If you have belts, they must have a safety shield.
-
13" hitch height maximum.
-
26x 12x 12 tire size maximum (can be sharpened).
-
Pump gas or racing gas allowed, no alcohol or nitro.
-
No electric fuel pumps.
-
Canister type coil, no high performance alterations (discretion of officials).
-
Water cooled engines and overhead valves permitted.
-
60" Wheelbase max.
-
Dead Man throttle (must return to idle automatic).
-
Must have working kill switch with 2 inch ring.