Briggsracing.com
Briggs&sTraTTOn
CORPORATION
POsT OffICe bOx 702
MIlwAukee, wI 53201 usA
414 259 5333
©2008 Briggs & Stratton Corporation
MS-5702-4/08
Table of ConTenTs
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WoRlD foRMUla
General Specs ......................................................................................3
Special Tools.........................................................................................3
Torque Specs ........................................................................................3
Racing Specifics...................................................................................3
Optional Performance Parts................................................................3
Highlighted Features............................................................................3
Cylinder Assembly Parts Explode................................................4
Head Assembly Parts Explode.............................................................5
Housing & Flywheel Parts Explode......................................................6
Carburetor Assembly Parts lode....................................................7
Clutch Assembly Parts Explode......................................................8
Starter Assembly Parts Explode......................................................9
Control Bracket & Gasket Sets Parts Explode................................ 10
PZ26 Carburetor Tuning Guid..................................................... 11
Electric Starting System iring Diagram ........................................ 12
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1
Briggs & stratton does not approve or authorize the use of these engines on 3 wheel all terrain vehicles (atvs), motor Bikes, fun/recreational go-karts, or
aircraft products. use of these engines in such applications could result in property damage, serious injury (including paralysis), or even death. this engine
requires special technical expertise and preparation Before it can Be used in competitive events.
2
WoRlD foRMUla
Installing Cylinder Head Plate
GeneRal sPeCs
Torque to 90 - 120 in-lbs.
(10 - 14 nm)
Model: 124335
Type: 8105
Torque to
70 - 90 in-lbs.
(7.9 - 10.1 nm)
Displacement: 12.48 Cu. in.
- 206 cc
Design: Slant, 30 degree,
Overhead Valve, Electric Start
Bore: 2.6875/2.6885 in.
Stroke: 2.2 in.
Compression Ratio: 9.5 to 1
Factory Timing: 29 degrees BTDC
sPeCIal Tool ReQUIReMenTs
General Model 12 Manual Part No. 272147
PVL Flywheel Puller Part No. 19584
Flywheel Wrench Part No. 19433
adjusting Valve Clearance
ToRQUe sPeCs
Description
air guard
Blower housing
carburetor (to manifold) 10mm
connecting rod t27
cylinder head Bolts 10mm
exhaust Brace screws 10mm
exhaust stud
flywheel nut
flywheel fan
intake (to cylinder) 5mm allen
oil drain plug
pvl module
Wrench/socket size
torque
7mm
40-50 lb-in. (4.5-5.6 nm)
60-110 lb-in. (7-12.5 nm)
80-110 lb-in. (9-12.4 nm)
140-150 lb-in. (1617 nm)
200-220 lb-in. (20-27 nm)
95-125 lb-in. (11m)
95-125 lb-in. (11-14 nm)
55-75 ft-lbs. (74.5-101 nm)
180-240 lb-in. (20-27 nm)
70-90 lb-in. (8-10.2 nm)
100-125 lb-in. (11-14 nm)
20-35 lb-in. (2.3-4 n
10mm & 3/8"
Torque to 50 - 70 in-lbs.
(6 - 8 nm)
10mm
15/16
10mm
eeler Gauge
3/8"
7mm
rocker arm stud
rocker arm plate
rocker arm set screw 1/8" allen
spark plug
side cover
starter gear
top control plate
valve cover
7/16"
10mm
90-120 lb-in. (10-14
70-90 lb-in. (0.1 nm)
50-70 (5.-7.9 nm)
95--in. (11-16.4 nm)
95-125 lb-in. (11-14 nm)
35-53 lb-in. (4-6 nm)
5/8" deep
10mm
#2 phillips
10mm
HIGHlIGHTeD feaTURes
· Dual Ball-Bearing, RACING Reinforced Cylinder
· Billet Rod
70-90 lb-in. (8-10 nm)
10mm lower & 3/8" 30-60 lb-in. (3.5-7 nm)
· Slotted, Stelite-Faced, Ground Cam w/ Compression Release
· Dual, High-Silicon Valve Springs
RaCInG sPeCIfICs
· PVL™ Digital Ignition System w/7,100 RPM Limiter
· CNC D-Shape Intake Port
· Walbro™ Round -Slide Carburetor
· Dana™ Fire-Ring Head Gasket
· Racing Crankshaft w/ Induction-Hardened Crankpin
· Green™ Air Filter
· Federal Mogul™ Moly-Coated Cam Ground, Barrel-Faced Piston
· Chrome-Faced, Racing Only Ring Package
· Port-Liner, Exhaust System
PVL™ Ignition Module Gap - .010/.014 (.15/.36mm)
Digital Rev Limiter - 7,000 RPM +/- 50
Spark Plug - Champion™ RG4HC
Fuel Requirements - 98 Octane (RON)
Recommended Oil Capacity - 16 oz., High Grade 30 Weight
(Even for initial break-in)
Exhaust System Requirements-50mm x 57mm Flex Coupling,
50/90 Canister Muffler.
Starter System-12 Volts @ 20 Amp Capacity-180 Cold Cranking
amps. Refer to your sanctioning body rules for required
installation location.
· Mikuni™ Fuel Pump
· Noram™ Clutch w/ Quick Change Sprocket Set
· Automotive 3-Piece Valve Retainer System
· Beefy Rocker Arm Stud Nuts
oPTIonal PeRfoRManCe PaRTs
High - G/Force Breather Bypass System - Part No. 555688
3
WoRlD foRMUla cylinder assembly
(engine Model series 124335)
55513 Ring Set
555664 Ring Set
557121 Piston Assembly
(.10" Over - Contains 10 Top Rings)
(Std.)
(Std., with File to fit Top Ring)
272147 Repair Manual
55514 Ring Set
555665 Ring Set
557122 Piston Assembly
(.20" Over - Contains 10 Top Rings)
(.10" Over)
(.10" Over, with File to fit Top Ring)
55515 Ring Set
555666 Ring Set
557123 Piston Assembly
(.30" Over - Contains 10 Top Rings)
(.20" Over)
(.20" Over, with File to fit Top Ring)
555667 Ring Set
557124 Piston Assembly
(.30" Over)
(.30" Over, with File to fit Top Ring)
699359 Flywheel Nut†
555140 Bushing/Seal Kit
692600 Breather Tube
299819s Oil Seal
555688 Breather Assembly
(Magneto Side)
(Optional, Also includes 691890 Rocker Cover Gasket)
555680 Cylinder Shield
699483 Metric Screw
(Cylinder Shield)
699485 Crankcase Gasket•
557135 Crankshaft
691664 Screw
(Connecting Rod)
557117 Connecting Rod
222698S Oil Drain Plug*
691663 Oil Drain Plug
(Magnetic, Optional)
555687 Cylinder Assembly
555579 Locating Pin*
695087 Timing Gear†
692517 Bearing•
698024 Ball Bearing†
691686 Flywheel Key
281658 Oil Fill Cap•
281568 Plug•
557117 Connecting Rod
499423 Piston Pin
691866 Piston Pin Lock
690979 Woodruff Key†
557041 Camshaft
555652 Crankshaft Endplay Shim
(Contains .007, .012, .018, & .025)
281658s Oil Fill Cap•
555630 Crankcase Cover
692550 Oil Seal•
*Included with 555687 Cylinder Assembly
(PTO Side)
(Includes all parts shown)
699478 Screw
Included with Respective Piston Assembly
(Includes all parts shown)
(Crankcase Cover/Sump)
† Included with 557135 Crankshaft
Briggs & Stratton Racing Oil (part #100104) by valvoline
was specifically co-developed and verified to offer superior
protection and performance in our racing engines. it is the only oil
recommended and proven for use in our racing engines.
Included with 555520 Piston Pin
4
WoRlD foRMUla head assembly
(engine Model series 124335)
699481 Hex Washer Head Metric Screw
(Rocker Cover Bottom)
692557 Hex Washer Head Screw
(Rocker Cover Top & Sides)
555679 Rocker Cover
691890 Rocker Cover Gasket*
557045 Exhaust Manifold
691764 Hose Connector
694543 Rocker Arm Adjuster*
694544 Rocker Arm Stud*
557015 Rocker Arm*
699230 Hex Washer Head Metric Screw
557016 Valve Cap*
(Cylinder Head Plate)
557025 Valve
Retainer*
691343 Push Rod Guide*
557047 Exhaust Gasket
557024 Valve
698214 Cylinder Head Plate*
Spring*
(Intake & Exhaust)
694088 Cylinder Head
Plate Gasket*
557026 Retaining
Ring* (Exhaust)
555645 Valve Guide Bearing*
(.002" Over)
557099 Washer
(Exhaust Manifold)
557097 Stud (Exhaust Manifold)
699482 Hex Washer Head Metric Screw*
(Cylinder Head)
557039 Spark Plug
555690 Heat Disperser (Optional)
557108 Stud
557133 Cylinder Head Assembly
(Intake Manifold)
555646 Nut*
(Intake Manifold)
55698 Cylinder Head Gasket*
557099 Washer*
(Intake Manifold)
693517 Push Rod
557017 Intake Valve*
557018 Exhaust Valve*
557098 Valve Tappet
*Included with 557133 Cylinder Head Assembly
5
WoRlD foRMUla housing & flywheel
(engine Model series 124335)
555577 Label Kit
557125 Magneto Armature
557128 Starter Ring Gear
(Includes 4 Pcs. 557129 - Screw)
699477 Metric Screw
(Magneto Armature)
698039 Starter
Drive Cover
555568 Stop Wire
(Used on Type No. 8002 & 8003)
557126 Flywheel
699201 Screw
(Flywheel Fan)
557134 Blower Housing
699201 Screw
555629 Hex Washer
(Starter Drive Cover)
Head Metric Screw
(Blower Housing)
692592 Flywheel Fan
699359 Hex Jam Nut
(Flywheel - M6 x 1.5)
555702 Cylinder Cover Insert
557107 Metric Screw
(optional)
(Rewind)
19433 Flywheel Wrench
19069 Flywheel Puller
555629 Hex Washer Head Screw
691678 Hex Washer Head Screw
(Blower Housing - 5/16 - 18unc)
19584 Flywheel Puller
555255 Rewind Guard
692591 Flywheel Cup (Optional)
695287 Rewind Starter
6
WoRlD foRMUla carburetor assembly
(engine Model series 124335)
557081 Needle Jet
555647 Throttle
Cable Boot
557083 Throttle Valve
555650 Needle Valve
Retainer
(Contains 5 Clips & 5 Retainers)
698973 Air Cleaner
557096 Air Cleaner
(Water Repellent Cover,
Optional)
557088 Throttle
Cable Cap
690939 Nut+
(Carburetor)
557087 Throttle
Return Spring
555586 Idle Speed Kit
557007 O-Ring Seal*
Pilot Jet
557086 Emulsion Tube
557130 Carburetor Spacer+
557012 Main Jet
(Gasoline - Contains: 30 & 34 mm Pilot Jets: 93, 95,
96 & 100mm Main Jets)
557131 Clamp
(Intake Manifold)
555648 Needle Float Valve
*
5555Idle Mixture Kit
557009 Intake Manifold
557080 Carburetor Float
100094 Air Cleaner
557044 Intake Gasket*
Recharging Kit
(Optional)
557082 Float Bowl Gasket*
555610 O-Ring Seal
557006 Carburetor Assembly
(Does not contain Carb Spacer, Clamp,
Manifold, Gasket, Air Cleaner or Main Jet)
*557089 Carburetor Overhaul Kit
+555646 Metric Screw/Nut Kit (Carb to Spacer)
557008 Float Bowl
555607 Carburetor Bowl Drain
7
WoRlD foRMUla clutch
(engine Model series 124335)
557023 Centrifugal Clutch Assembly
(Does not contain Radius Washer 2400025)
557115 Snap Ring
557116 Cartridge Springs Kit
(Includes 3 Orange & 3 Yellow)
557114 Clutch Cartridge
(Includes Springs)
557111 Clutch Drum
557115 Snap Ring
557112 Clutch Hub Shaft
557113 Clutch Thrust Spacer/Bearing
557019 Mounting Hardware
557020 Clutch Gear (17T, #219)
557021 Clutch Gear (16T, #219)
557092 Clutch Gear (19T, #219)
557091 Clutch Gear (18T, #219)
2400025 Raduis Washer
(Required for inboard mounting,
included with Clutch Assembly)
8
WoRlD foRMUla starter assembly
(engine Model series 124335)
*Included with 557068 Starter Assembly
+Included with 557073 Brush Retainer
557120 Screw
690323 Screw*
(Support Bracket)
(Starter Motor)
557119 Support Bracket
(Starter)
691532 Starter Strap
691286 End Cap*
691293 Brush Retainer*
497608 Brush Set*+
690635 Clamp
(Starter Solenoid)
557072 Starter Housing*
691029 Nut*+
(Brush Retainer)
692966 Starter Armature*
691261 Washer*+
(Brush Retainer)
557067 Starter Solenoid
692353 Pinion Gear
790537 Screw
499308 Starter Drive*
(Starter Motor Mounting M8 x 1.25)
694482 Drive Cap*
691265 Retaining Ring
9
WoRlD foRMUla control bracket & gasket set
(engine Model series 124335)
808656 Fuel Pump
793379 Stop Wire
(Used on Type No.(s) 8104, 8105, 8106)
692602 Stop Wire
(Rocker Switch,
Used on Type No. 8002)
699479 Metric Screw
(Control Panel)
555699 Control Panel
557028 Starting Switch
*Included with 557110 Engine Gasket Set
+ Included with 557027 Valve Gasket Set
557044 Ie Gasket*+
694088 Cylinder Head Plate Gasket*+
699485 Crankcase Gasket*
691890 Rocker Cover Gasket*+
299819s Oil Seal*
692550 Oil Seal*
555698 Cylinder Head Gasket*+
(Magneto Side)
(PTO Side)
10
PZ26 Carburetor Tuning Guide
If a smooth idle cannot be obtained with the Idle Mixture
screw between 1/4 - 2 turns out from closed, a different
size Pilot Jet may be needed. The proper size Pilot Jet will
allow for smooth acceleration from an idle and steady
engine speed up to 1/4 throttle opening.
Midrange / Part Throttle
The Jet Needle primarily controls fuel flow between 1/4
and 3/4 throttle opening. The Jet Needle has five notches
and a C-clip on the top of it. To richen the part throttle
operation, move the clip to the next lower notch. This will
hold the needle farther out of the nozzle. To lean the
part throttle operation, move the clip to the next higher
position. The highest notch (farthest from the narrow tip)
is considered the 1st position. Needle taper reference
letters are stamped on the needle for identification.
High speed / full Throttle
The Main Jet controls the fuel flow at throttle positions of
1/2 to full throttle. Thjet size or diameter in millimeters
amped on the jitude and weather conditions can
effect the engne operation enough to require changing
the size of the Main Jet. High air temperature, humidity, or
altitude could require a smaller Main Jet. Low temperature,
humidity, or altitude would require a larger diameter Main
Jet. Running the engine with an improper Main Jet could
rein a loss of power, high engine temperatures, or
endamage.
float Height
PZ Carburetor General specifications
Gasoline
Main Jet - #102
Pilot Jet - (slow Jet) #37
Jet needle - CDb 4th notch
Main nozzle diameter - 2.6 mm
Idle Mixture screw turns out - 1-1/2
float Height* - 14.0mm
Torque specifications
The float height controls the fuel level in the float bowl,
which can also effect carburetor performance. Set flo
height according to specification before any othenin
The float height may need to be adjusted for besperfor-
mance on different track types.
Idle / low speed
Tuning of the engine at idle and low speeds is accomplished
by adjusting the Idle Mixture Screw or changing the size of
bowl screws 17 – 20 in-lbs.
the Pilot Jet (also called Slow Jet). The jet size or diameter in Pilot Jet 9 – 12 in-lbs.
millimeters is stamped on the jet (37 = .37mm orifice). The
Idle Mixture Screw is a fuel adjustment, so closing the screw
or turning it clockwise will lean the fuel mixture, and opening
the screw or turning it counterclockwise will richen the
needle Jet 14 – 16 in-lbs.
Main Jet 9 – 11 in-lbs.
fuel mixture.
To adjust the Idle Mixture Screw proceed as follows. Turn
the Idle Mixture screw in until it lightly seats or stops. Back
the screw out the specified number of turns. Warm the
engine and set the Idle Speed screw slightly higher than
the desired idle rpm. Turn the Idle Mixture screw in or out
to obtain the highest rpm. Turn the Idle Speed screw to the
desired idle rpm. A slightly rich idle mixture is usually better
for acceleration.
11
WoRlD foRMUla electric starting system
(engine Model series 124335)
Electric Start Wiring Diagram
12
log book
DaTe
WoRK PeRfoRMeD
seal nUMbeR WoRK PeRfoRMeD bY
1/31/08
example: Replaced Air Cleaner
DK
13
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