SECTION 9 - F200 TECHNICAL SPECIFICATIONS
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| 9.1
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Approved, commercially available, single cylinder air cooled overhead valve engines.
200 cc's maximum displacement. See Chart for approved engines. |
| 9.2
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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
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Exhaust System: See rule 8.3 |
| 9.4
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Carburetor: Any commercially available butterfly type Tillotson HL series carb.
Minimum/maximum venturi diameter = .750/.790”. Minimum/maximum throttle bore diameter
= .990/1.010”. Metering holes non tech. Restrictor plates will be used in all Junior
classes. See Section 8.8 for details. Filter cups, adapters and air filters non
tech items. The carburetor pulse passage is non tech but can not be used to bypass
the restrictor plate. Its sole and intended purpose it to actuate the fuel pump
inside the carburetor. Pulse type fuel pumps permitted.
|
| 9.5
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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 and they must be
present in grooves), flat top or dished piston. (No domed or pop up types) Rings
and wrist pin non tech but must be of steel (ferrous) material. 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 the 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 90º 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 – Briggs W/F head legal
but must use a 14mm spark plug) |
| |
9.11.1
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Cylinder head repair. Aside from the above, each engine brand will be allowed an
approved area on the inlet and exhaust tracts for external repair of broken through
“thin cross sections” during the porting process if deemed necessary. The area shall
be no greater than a .5” (1/2”) square and either epoxy or welding is acceptable.
This repair has to be confined to the “approved” area shown on the list below.
|
| 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 with a minimum stem diameter of .188” (4.77mm). Stock OEM rocker arms only
(with no alterations to their stock ratio). No interchange of rocker arms between
engine brands. Stock (Briggs) OEM cylinder head plates only. Rocker arms and (Briggs)
cylinder head plates 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. 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. Cam and crank gear non tech. |
| 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. |
| 9.18
|
Coatings: Wear type coatings allowed on valve train, valves, camshaft, wrist pin
and crankshaft only. Coatings of any type not allowed on block, head, piston, rod
or side cover. |
| 9.19
|
Crankcase breathers are to be routed internally through the valve cover as originally
intended in OEM configuration. No additional breathers allowed. |
| 9.20
|
Approved flywheels are the ARC models 6606, 6608, 6613 (w/starter ring gear), 6614
and the UMMF model FA-100 and the FS-1001. Briggs Animal flywheel (JR Racecar type
pt #699305) |
| 9.21
|
Tires: See Section 4.1 for Oval specifications and 4.50 for Sprint |
| 9.22
|
New 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 |
 |
Approved Port Repair Areas. See 9.11.1 for details.
 |
F200 and BNSS are registered trademarks of Burris Racing. Any use or advertising
of these rules or the BNSS and F200 trademarks with out the consent of Burris Racing
is strictly forbidden. To guarantee the integrity and global continuity of the BNSS
and F200, any alteration to these rules or programs while running under the guise
of F200 or BNSS formats is strictly forbidden. |
