Classes

 

The 2011 Missouri River pulling class list is a tad bit different than what most are used to. We have combined a couple classes to make them larger and more competitive. The days of everybody having their own class is over. The list of classes are below with the class rules following. Please read completely to make sure you are in the correct class.

All 2011 weight class will be 1000 lbs and 1050 lbs due to some tractors weighing more than others and not meeting the 950 weight limit.

 

Class List

Governed 10hp
Governed 11-14hp
Governed 15-16hp
Governed 0-20hp belt
Limited Twin
Sport Stock
Stock Altered Single
Stock Altered Twin
NQS Superstock
MR V-twin Superstock

 

Governed 10hp

1. Class is open to all tractors belt and clutch. All tractors must run a naturally aspirated Kohler flathead 10hp or lower engine only. No other engines are allowed in this class. This class is an entry level pulling class and is limited to the motor restrictions to keep the class fair and competitive. Other brands and flavors of motors may pull in this class but are not eligible for any Missouri River points, trophies or cash payouts.
2. Tractor must meet all general, safety and chassis rules.
3. Motors are to be the following:
   -Stock bore with maximum .030 oversized (Tech)
   -Stock Stroke (Tech)
   -Stock Valve diameter and valve lift (Tech)
   -Stock un-ported ports (Tech)
   -Stock Kohler #26 carburetor no ventuie modifications (Tech)
   -Stock un-altered cylinder head (Tech) Comment: May be milled for clean up.
   -Steel flywheels are recommended but not mandatory.
   -No piston pop out (Tech)
   -No carb spacers (Tech)
   -Gasoline only (Tech)
4. Engines must be governed at 4250 RPM with no exceptions (See RPM protest)
5.  Tractors must use an OEM garden tractor frame. Tractors must have a front grill and hood. (Tech)
6. Tractors front axle must bolt with in the factory frame that is being used with a maximum of 50 inch wheel base (Tech)
7. Tractors must have a working reverse powered by the engine. (Tech)

 

Governed 11-14hp

1. Class is open to all tractors belt and clutch. Tractors in this class have to option to run a naturally aspirated Kohler flat head single cylinder 14hp or lower engine or any commercially available over head valve single cylinder engine 14hp or lower only. This class is a single cylinder class only. Please note the differences in what can be done and what is being checked between the two motors. Tech procedure for the Kohler flat heads is posted. The over head valve motors are a different story. If the overhead valve motor is protested we will check all items that have tech by them. The owner WILL provide the tech official with a factory HP listing and a factory model number for the motor being checked. At that time we will determine what the factory OEM tech sizes are even if it means that we have to purchase a motor to get the information. It is not our responsibility to do research on all motors that are available so buy and pull motors at your own risk…..
2. Tractor must meet all general, safety and chassis rules.
3. Motors are to be the following:
   -Stock bore with maximum .030 oversized (Tech)
   -Stock Stroke (Tech)
   -Stock Valve diameter and valve lift (Tech)
   -Stock un-ported ports (OHV MOTORS ONLY) (Tech)
   -Stock carburetor no ventuie modifications (Tech)
   -Stock un-altered cylinder head (Tech) Comment: (OHV engines may mill .010 max from stock)
   -Stock top side piston profile (OHV MOTORS ONLY) (Tech)
   -Steel flywheels are recommended but not mandatory.
   -No piston pop out (Tech)-
   -No carb spacers (Tech)
   -Gasoline only (Tech)
4. Engines must be governed at 4250 RPM with no exceptions (See RPM protest)
5. Tractors must use an OEM garden tractor frame. Tractors must have a front grill and hood. (Tech)
6. Tractors front axle must bolt with in the factory frame that is being used with a maximum of 50 inch wheel base (Tech)

 

Governed 15-16hp

1. Class is open to all tractors belt and clutch. This class can run either a flat head Kohler single, OHV Kohler single or a Briggs and Stratton 16hp or under.
2. Tractor must meet all general, safety and chassis rules.
3. Motors are to be the following:
   -Stock bore with maximum .030 oversized (Tech)
   -Stock Stroke (Tech)
   -Stock Valve diameter and valve lift (Tech)
   -Flat Tappet cam and lifters (Tech)
   -Stock un-ported ports (Tech)
   -Stock top side piston profile (Tech)
   -Stock carburetor must be used that came on that particular brand and model. Example: No K-series carbs on an OHV Kohler. No venturi modifications (Tech)
   -Stock cylinder head must be used. No recast heads allowed. (Tech)
   -Steel flywheels are recommended but not mandatory.
   -No piston pop outs. (Tech)
   -No carb spacers unless the spacer is an OEM factory part that came on that brand and motor model. (Tech)
   -Gasoline only (Tech)
4. Engines must be governed at 4250 RPM with no exceptions (See RPM protest)
5. Tractors must use an OEM garden tractor frame. Tractors must have a front grill and hood. (Tech)
6. Tractors front axle must bolt within the factory frame that is being used with a maximum of 50 inch wheel base (Tech)

 

Governed 0-20 HP Belt

1. Class is open to all belt tractors. Motor used must be of garden tractor type and have a maximum of 20 HP. Single cylinder and twins allowed.
2. Tractor must meet all general, safety and chassis rules.
3. Motors are to be the following:
   -Stock bore with maximum .030 oversized (Tech)
   -Stock Stroke (Tech)
   -Stock Valve diameter and valve lift (Tech)
   -Flat Tappet cam and lifters (Tech)
   -Stock un-ported ports (Tech)
   -Stock carburetor must be used on that brand of motor and model. No venturi modifications (Tech)
   -Stock cylinder head must be used. No recast heads. (Tech)
   -Steel flywheels are recommended but not mandatory.
   -Stock pistons must be used. No piston pop outs. (Tech)
   -No carb spacers unless the spacer is an OEM factory part that came on that brand and motor model. (Tech)
   Gasoline only (Tech)
4. Engines must be governed at 4250 RPM with no exceptions (See RPM protest)
5. Tractors must use an OEM garden tractor frame. Tractors must have a front grill and hood. (Tech)
6. Tractors front axle must bolt within the factory frame that is being used with a maximum of 50 inch wheel base (Tech)

 

Limited Twin

1. 1. Class is open to all tractors belt and clutch. Tractors in this class have the option to run 5 different engines with 5 different sets of rules and will all pull together so please read carefully. Engines that are allowed in this class are

• 35 Cube Briggs and Stratton Vanguard V-twin
• 38 Cube Kohler Command V-twin
• 38 Cube Briggs and Stratton Vanguard V-twin
• 44 Cube Kohler Command V-twin
• 48 Cube Kohler flathead opposed twin (Still Working on Rules)

 

35 Cube Briggs Vanguard

1. Tractor must meet all general, safety and chassis rules.
2. Motors are to be the following.

• Stock bore with maximum .020 oversized (Tech)
• Stock Stroke (Tech)
• Stock valve diameter and valve lift (Tech)
• Flat Tappet cam and lifters (Tech)
• Stock un-ported ports (Tech)
• Stock OEM Briggs cylinder head (Tech)

 

 

38 Cube Briggs Vanguard and Kohler Command

1. Tractor must meet all general, safety and chassis rules.
2. Motors are to be the following.

• Stock bore with maximum .020 oversized (Tech)
• Stock Stroke (Tech)
• Stock valve diameter and valve lift (Tech)
• Flat tappet cam and lifters (Tech)
• Stock un-ported ports (Tech)
• Stock top side piston profile (Tech)
• Stock OEM un-altered chamber cylinder heads (Tech) (Comment: Must have a factory casting number)

 

44 Cube Kohler Command

1. Tractor must meet all general, safety and chassis rules.
2. Motors are to be the following

• Stock bore with maximum .020 oversized (Tech)
• Stock Stroke (Tech)
• Stock valve diameter and valve lift (Tech)
• Stock camshaft duration lobe separation (Tech)
• Flat tappet cam and lifters and stock un-altered rocker arms (Tech)
• Stock un-ported ports (Tech)
• Stock top side piston profile (Tech)
• Minimum of a .025 thick head gasket (Tech)
• Stock OEM cylinder heads only (Tech) (Comment: Must have a factory casting number)
• Heads will be teched for stock un-altered open combustions chamber and 44 cube diameter. Will also be checked for milling. Maximum of .010 can be removed for clean up.

 

All Engines

1. Steel flywheels are recommended but not mandatory.
2. Gasoline only (Tech)
3. All engines must run an OEM factory carburetor for the model of engine running. Ventrui of carb must remain stock and may not be modified an anyway. Carburetor must bolt to an OEM intake with a maximum of a ½ adapter. Jetting modifications are allowed. (Tech)
4. Engines must be governed at 4250 RPM with no exceptions (See RPM protest)
5. Tractors must use an OEM garden tractor frame. Tractors must have a front grill and hood. (Tech)
6. Tractors front axle must bolt with in the factory frame that is being used with a maximum of 50 inch wheel base (Tech)

 

Sport Stock Twin

1. Stock engines (block, stroke, heads, valve covers, intake manifold, carburetor). No dome pistons allowed. Engine size must not exceed 39 cubic inches (allows for .030″ overbore) for ohv motors or 48 cubic inches (allows for .020 overbore) for flatheads. Interchanging parts between different brand motors WILL NOT BE ALLOWED.
2. Stock downdraft carburetor may have adjustable needle added. No other alterations allowed. OEM accelerator pump carburetor is allowed. No other types of carburetors allowed. Maximum one (1) carb with (1) venturi allowed. No turbos or pressurized intakes.
3. No two-barrel manifolds and no aftermarket manifolds allowed. Cutting or welding on manifold is not allowed. Vertical intake carb adapter is allowed.
4. No reverse port engines allowed. Manifolds and carburetor must go to the original stock ports.
5. Stock heads may be reworked, but recast or aftermarket heads are not allowed. Porting and polishing allowed. OEM closed chamber heads are allowed. No external welding or other external modifications allowed. Must use stock intake and exhaust bolt pattern and location.
6. Engines must use stock lift cams, stock length valves, and stock rocker arms. Pushrod guide plates allowed on OHV twins. Aftermarket lifters are allowed but must be flat tappet, no roller lifters.
7. Engine must have been available in a lawn or garden tractor from an oem manufacturer not to exceed any other rules such as horsepower, cubic inch, cylinders, or class size rules, etc., and must be oem stock production garden tractor engine. Aftermarket blocks are not allowed. It is up to the tractor owner to provide documentation to prove eligibility, such as oem tractor manufacturer, tractor model, and engine specs such as cylinders, cubic inch, and horsepower rating.
8. No rpm limit but steel flywheels are REQUIRED.
9. Engines must run gasoline, E10, E85 only; service station pumped gasoline, no additives. Racing gas is allowed.
10. Must run a factory appearing hood and grill, use garden tractor rear-ends and stock garden tractor frames that are factory length with a maximum wheelbase length of 52 inches.

 

Stock Altered Single

1. Single cylinder four cycle flathead engines only and must be Kohler, Wisconsin, Tecumseh or Briggs.
2. Engine blocks must have an OEM stock appearance and must be factory productions or their OEM replacement with factory deck height. No Woolam or J2 blocks allowed
3. Stock Head bolt pattern, location and size. Stock head gasket must fit over studs or bolts.
4. Maximum crankshaft stroke 3.25″ and engine bore 3.780″. Maximum 0.010″ measuring tolerance, must not exceed 36.5000 cubic inch limit.
5. Maximum engine valve size 1.380 with maximum 0.001″ measuring tolerance and maximum engine valve lift .330″ with maximum 0.003″ measuring tolerance.
6. Maximum carburetor venturi size 1.00″, no air entering after 1.00″ restriction. Venturi must be round in shape. Note, this is referring to the venturi, not the throttle or choke bore.
7. Carburetor must be a stock appearing Kohler-type and must be mounted to the engine with no more than 1″ long spacer. No turbos or pressurized intakes.
8. No reverse port engines allowed, carburetor must go to the original stock intake port.
9. Billet heads permitted with minimum one (1) inch thickness.
10. Porting and polishing allowed
11. No rpm limit but steel flywheels are REQUIRED.
12. No starter-generators allowed. Must use ring gear starter or starter-cart.
13. No external welding except for crankcase area of the block for repair. But no other external modifications allowed.
14. Engines must run gasoline, E10, E85, E99, racing gas or methanol only; no additives. Driver must wear full fire suit if tractor is on methanol.
15. Must run a factory appearing hood and grill, use garden tractor rear-ends and stock garden tractor frames that are factory length with a maximum wheelbase length of 52 inches.
16. Engines must have a hold down restraint installed to prevent the cylinder and head from separating from the block.

 

Stock Altered Twin

1. Stock engines (block, stroke, heads). Engine size must not exceed 39 cubic inches for ohv motors or 48 cubic inches for flathead twins.
2. Stock carburetors may be reworked. OEM accelerator pump carburetor is allowed. OEM Kohler 2-barrel carb and recast 1.2 stock appearing carb are allowed. No other types of carburetors allowed. Maximum one (1) carb allowed. No turbos or pressurized intakes.
3. No reverse port engines allowed. Manifolds and carburetor must go to the original stock ports.
4. Stock heads may be reworked, but recast or aftermarket heads are not allowed. Porting and polishing allowed. No external welding or other external modifications allowed. Must use stock intake and exhaust bolt pattern and location.
5. Aftermarket cams, pushrods, valve springs and solid lifters allowed. Roller lifters and roller rockers are allowed.Engine must have been available in a lawn or garden tractor from an oem manufacturer not to exceed any other rules such as horsepower, cubic inch, cylinders, or class size rules, etc., and must be oem stock production garden tractor engine. Aftermarket blocks are not allowed. It is up to the tractor owner to provide documentation to prove eligibility, such as oem tractor manufacturer, tractor model, and engine specs such as cylinders, cubic inch, and horsepower rating.
6. No rpm limit but steel flywheels are REQUIRED.
7. Engines must run gasoline, E10, E85, E99, racing gas or methanol only; no additives.
8. Must run a hood of some sort, use garden tractor rear-ends and stock appearing garden tractor frames with a maximum wheelbase length of 56 inches.
9. Tractors conforming to the Missouri Super Stock class rules may pull in this class.