Burris National Speedway Series – 2004 Season Rule Book

SECTION 9 -               F200 TECHNICAL SPECIFICATIONS

9.1              Approved, commercially available, single cylinder air- cooled overhead valve engines.   200 cc's maximum displacement.   See Chart for approved engines.

9.2              Block, Cylinder Head, Crankshaft and Side Cover:  Must be approved OEM items.   Cylinder head, block and side cover external surfaces may be machined to remove excess material from mounting bosses, cast in brackets, etc that are no longer in use.   No external machining allowed to enhance performance.

9.3              Exhaust System:  See rule 8.3

9.4              Carburetor:  Any commercially available butterfly type Tillotson HL series carb.   Maximum venturi diameter = .790” Seniors and Jr lll, .735” for Jr ll and .635” for Jr l. Maximum throttle bores are as follows; .790” carbs = 1.010”, .735” carbs = .885” and .635” carbs = .820”. Metering holes non- tech.   Filter cups, adapters and air filters non- tech items.   Pulse type fuel pumps permitted.

9.5              Fuel:  See rule 8.1 and 8.1.2

9.6              Intake manifold:  Aluminum only.   Maximum mean inlet tract length is 2".   Length determined by adding the longest and shortest tract distances (flange to flange) together and dividing by 2.

9.7              Connecting Rods:  Aluminum only.   (Fasteners and inserts/bushings  excluded)  Stock length (plus or minus .010") to be maintained.   See chart for specific details.

9.8              Pistons:  Any aluminum three ring (compression, scraper and oil), flat top or dished piston.   (No domed or pop up types) Rings and wrist pin non- tech. OEM wrist pin diameter to be maintained.   See chart for maximum bore size and wrist pin diameter for a specific engine.

9.9              Crankshaft:  Standard OEM item with stock stroke length (plus or minus .010").   Thermal treating and shot peening permitted.   Minor grinding for camshaft clearance permitted.   No other alterations allowed.   See list for specific stroke details.

9.10          Flywheel and Ignition Coil:  Aftermarket or OEM flywheels permitted.   If OEM flywheel is used it must be unaltered and meet minimum listed weight and stock OEM coil (ignition system) must be used.   Approved aftermarket flywheels only may be used.   Spec diameter and weight as follows; 6.75” +/- .25”dia.  X  4.75 lbs +/- .75 lbs.   When using aftermarket flywheels, any approved OEM F200 coil may be used on any engine.  (i.e.  Briggs coil on a Honda, Tecumseh coil on a Kohler, etc) External coil modifications to facilitate mounting are legal. Coil mounts, flywheel key, spark plug boots and plug wires are non tech items. See below for approved flywheels.

9.11          Cylinder Head:  Original factory casting only.   Two valves maximum and must maintain original location, (angles are 90Ί from deck with listed spacing).  Carb inlet and exhaust outlet in the head have to be in their stock intended locations.  Porting and grinding permitted.   No external addition of metal to enhance performance allowed.   Spark plug to be 14mm X .75 reach only and original stock location maintained.  Minimum combustion chamber volume when mounted on engine @ TDC is 24 cc's using prescribed procedure as noted in rule 8.5.   This is to be done after the event and when the engine has cooled down to a reasonable temperature. (Note - W/F head must use a 14mm plug)

9.12          Valve Train:  Push rods, push rod guide plates, retainers, springs, keepers, rocker adjusters, etc, non tech. Steel valves, springs and push rods only. Retainers may be of aluminum or steel. Intake valve diameter, 1.080" maximum, exhaust valve, .990" maximum. Stock OEM rocker arms only with no alterations to their stock ratio. Rocker arms may be welded or reinforced for strength. No other alterations to original configuration permitted. Flat tappets only, must be stock appearing. Unless otherwise specified no titanium components allowed.

9.13          Camshaft:  Maximum (actual) lift .275" measured at valve.   Cam and crank gear non- tech.  This is to be done after the event and when the engine has cooled down to a reasonable temperature. Note – If the camshaft has a compression release it needs to be taken into account when zeroing the indicator on the exhaust lobe.

9.14          Fasteners:  Non- tech, but must remain in original location.   Heli- coils, studs, etc allowed.

9.15          Gaskets:  Non- tech.

9.16          Lubrication system:  Must retain splash type oiling system.

9.17          Bearings: All Ball and roller bearings shall be of metallic (magnetic steel) construction (excluding retainers) and be of conventional design. This includes inner and outer races as well as the balls and rollers. No other materials allowed.

Approved flywheels are the ARC models 6606 and 6608 and the UMMF model FA-100 and the FS-1001.

Engines are to be submitted by the manufacturer (or its authorized representative) for approval no later than October 1st to be eligible for the following competition year. Approval is not automatic and is up to the discretion of the BNSS.

 

Approved Engines and Specifications

Make:

Briggs

Honda

Kohler

Tecumseh

Yamaha

Notes

Model:

Intek

5.5/6.5

 

GX200

C6 XKE

OHV 5.5

YF200 R1

Animal w/5.5 Intek crank allowed. W/F head allowed

Bore, Std:

2.688

2.679

2.638

2.797

2.598

Standard Bore

Bore, Max:

2.760

2.709

2.783

2.833

2.809

Maximum allowed

Increase:

0.072

0.030

0.145

0.036

0.211

Increase from std. bore

Stroke:

2.040

2.125

2.008

1.938

1.968

Standard Stroke +/- .010

Rod length:

3.375

3.303

3.425

3.484

3.324

Cntr to Cntr.  Tolerance is +/- .010

Rod length:

2.514

2.358

2.540

2.703

2.459

Inside length

Wrist pin dia:

0.625

0.708

0.550

0.563

0.630

Tolerance is +/- .0025

Rod journal

1.098

1.180

1.218

0.999

1.101

Tolerance is +/- .010

Flywheel

5.75 lbs

5.75 lbs

8.1 lbs

7.0 lbs

6.5 lbs

Approx.  weight in pounds

Valve spacing

1.382

1.219

1.380

1.250

1.181

Valve angles are 90Ί from deck