Burris National Speedway Series – 2003 Season Rule Book


SECTION 13 - TECUMSEH 10 HP STAR TECHNICAL SPECIFICATIONS


Tecumseh HM100 Kits 730587K, 756991K or 756992K, cyl. block 34922A

13.1  No Titanium components allowed. Coating or plating cylinder or internal engine parts
prohibited.
13.2 Clutch: Must be rim centrifugal clutch only. No disc clutches. End of crank bolt and
safely washer required.
13.3 Sheet metal: Must be intact and in place except for internal baffle and starter cover. Shroud may be cut for temperature sensor clearance. Exhaust mounted heat deflector is optional.
13.4 Exhaust: See rule 8.3. B91-MO silencer also legal.
13.5 Carburetor: Any HL Tillotson with a butterfly throttle assembly. Venturi must measure .900” NO-GO.
13.6 Intake Manifold: Must use Tecumseh part #34349A. Manifold may be drilled and
tapped for pulse line. May be mounted with longer studs to rotate carb for needle
access.
13.7 Cylinder Head: Must be stock. Fins may be modified for CHT lead mounting. 14mm helicoil is permitted. Head must have a minimum depth of .360” from the gasket surface to area in front of the spark plug. Compression release permitted.
13.8 Head Gasket: minimum thickness .043”
13.9 Cylinder Bore: max. 3.348”
13.10 Stroke: max. 2.544”
13.11 Decking: permitted with a maximum of .015” piston pop out.
13.12 Cam: Must be of stock origin. Maximum valve lift is .325”. Maximum intake and
exhaust duration is 265 degrees at .003 lift.
13.13 Valve Springs: Stock only
13.14 Block: #34096c or 36900k only. No porting is permitted. Intake valve seat must be 30 degrees at 1.190” I.D. max. Exhaust valve seat must be 45 degrees at 1.025” I.D. max. Multi-angle seats are not permitted.
13.15 Flywheel: Stock only. No modifications permitted. Electronic ignition motor 7lbs., 5ozs. Point ignition motors must use flywheel #610847 and stator #30561. No offset keys permitted.
13.16 Ignition: Must use factory motorsports ignition.
13.17 Side Cover: Pulse port allowed. Multiple vent tubes permitted. Peening of gasket surface permitted.
13.18 Lifters: Stock only.
13.19 Pistons: Stock only.
13.20 Piston Rings: Stock only.
13.21 Crankshaft: Stock only. Bearing must be stock. Crank gear is NONTECH. Repair of crankshaft flywheel end with a 3/8” stud allowed.
 
 

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