 1. Single engine
and cylinder flathead only. (No overhead valves). No ram
tubes or homemade heads. No stroker kits. No diesels, 2
strokes, or twin cylinders. No head plates. 2. Must have
wheelie bars with kill switch.
3. Maximum hitch
height: 13"
4. Wheel base
must be within 6" of factory specifications but no
more than 60".
5. Tractors must
have garden tractor rear ends. Locked rear ends permitted.
6. Tractors must
run factory looking hood and grill.
7. Engine must
retain stock valves, stock camshaft, and stock ignition.
Valves to be 1.37" to 1.36" for both intake and
exhaust.
8. Maximum fuel
density will be .750
9. Kohler cam
specs: +.005"/-.010"
| INTAKE |
EXHAUST |
INTAKE |
EXHAUST |
| TDC |
0� - .055" |
BBDC |
30� - .055" |
BBDC |
58� - .316 |
BTDC |
88� - .316" |
| ATDC |
20� - .125" |
BBDC |
10� - .125" |
BBDC |
28� - .260" |
BTDC |
58� - .260" |
| ATDC |
40� - .195" |
BDC |
0� - .160" |
BBDC |
8� - .195" |
BTDC |
28� - .160' |
| ATDC |
60� - .260" |
ABDC |
30� - .260" |
ABDC |
12� - .125" |
BTDC |
18� - .125" |
| ATDC |
90� - .316" |
ABDC |
60� - .316" |
ABDC |
32� - .055" |
ATDC |
2� - ..55" |
| BBDC |
74� - .324" |
ABCD |
76� - .324" |
� |
� |
� |
� |
10. Stock spec sheets will be
final say on all motors.
11. Fuel tanks can be relocated.
No pressurized fuel tanks.
12. Must have shields and guards
over belts and chains. No loose belts. Scatter shield
must be installed opposite cam side of motor.
13. Engine can be modified but
must remain in a 16 Horsepower block.
14. Tractor must have stock bore
and stroke with .030" clean up on bore.
15. arburetor must be mounted to
the motors with no more than a 1-1/4" spacer (including
gaskets) and must use the factory production intake.
16. Carburetor size cannot exceed
1" venturi. Only one carburetor is permitted.
17. Kohler engine must have
Kohler carburetor. Briggs engine must have Briggs
carburetor, etc.
18. One spark plug in stock
location.
19. Head shaving is permitted.
20. Porting and polishing is
permitted.
21. Stock camshafts must adhere
to specs in rules. Tractor must have easy access
including a drilled and tapped crank to accept a degree
wheel to allow tech committee to check lift and duration
or tractor must forfeit any winnings and points where
applicable.
22. Optional steel flywheel.
23. Weights and brackets will be
measured from center of rear axle forward and cannot
exceed 84". Cannot exceed 18" back from center
of rear axle and 12" out from sidewall of tires.
Total length of tractor including weights and brackets
cannot exceed 102". Total width cannot exceed 79".
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