Hirth F-23 - Hirth Engine Setting Values

26
Fastener Description Size Ft. lb
inch/lb
AIR GUIDE ATTACHMENT SCREWS AND BOLTS
6mm
6 Ft.Lbs.
72inch Lbs.
CYLINDER HEAD SCREWS
6mm
8 Ft.Lbs.
96 inch Lbs.
ELECTRONIC IGNITION BOX & IGN. COILS NUTS
6mm
7 Ft.Lbs.
84inch Lbs.
FAN HOUSING MOUNTING SCREWS
6mm
8 Ft.Lbs.
96inch Lbs.
FLYWHEEL DUST COVER (265C1)
6mm
6 Ft.Lbs.
72inch Lbs.
INTAKE MANIFOLD MOUNTING SCREWS
6mm
7 Ft.Lbs.
84inch Lbs.
RECOIL STARTER MOUNTING SCREWS
6mm
8 Ft.Lbs.
96inch Lbs.
CRANKCASE ASSEMBLY SCREWS
8mm
19 ft.Lbs.
228inch Lbs.
FAN PULLEY MOUNTING SCREWS
8mm
19 ft.Lbs.
228 inch Lbs.
ELECTRIC STARTER MOUNTING SCREWS
8mm
19Ft.Lbs.
228 inch Lbs.
CYLINDER BASE NUTS
8mm
19Ft.Lbs.
228 inch Lbs.
EXHAUST MANIFOLD MOUNTING SCREWS
8mm
19ft.Lbs.
228 inch Lbs.
EXHAUST “U” CLAMP NUTS
8mm
17Ft.Lbs.
204 inch Lbs.
GEARBOX DRAIN PLUGS (G-40 GEARBOX)
12mm
10Ft.Lbs.
120 inch Lbs.
CARBURETOR RUBBER INTAKE FLANGE SCREWS
8mm
8Ft.Lbs.
96 inch Lbs.
COOLING FAN MOUNTING NUT
10mm
37Ft.Lbs.
444 inch Lbs.
REDUCTION DRIVE MOUNTING SCREWS
10mm
37Ft.Lbs.
444 inch Lbs.
SPARK PLUGS (cold engine)
10mm
9Ft.Lbs.
108 inch Lbs.
CRANKSHAFT BOLT (PTO-end) (½ inch NF)
½” NF
46Ft.Lbs.
552 inch Lbs.
CRANKSHAFT NUT(Magneto end)
16mm
107Ft.Lbs
ENGINE MOUNTING BOLTS
10nn
37Ft.Lbs.
444 inch Lbs.
HIRTH ENGINE SETTING VALUES
Engine
F-23 VM slide carb
F-23 BN carb
F-23 E (Fuel Inj)
Ign.Timing@2000 - carbureted
16 deg.
16 deg.
Ign.Timing@2000 - Fuel injected
18 deg.
Spark Plug Heat Vl.
280
280
280
Spark Plug Gap
.030
.030
.030
No. of Carburetors/Injectors
Two
Two
2 injectors
Carburetor ID #
Mikuni
VM 34
389-2
Mikuni
BN 34
34-6
Main Jet
180
117.5 High Speed
Needle Jet
166P4
67.5 Low speed
Jet Needle
6DH3 1
st
clip pos.
Idle jet
25
Do Not Exceed RPM
6350
6350
6350
Peak HP RPM
6150
6150
6150
HP @ Peak RPM – Free air cooled
50
50
50
Peak Torque RPM
6150
6150
6150
Peak Torque Ft.Lb.
42
42
42
Maximum CHT
535
535
535
Maximum EGT – at full power
1256
1256
1256
Operating EGT – at full power Rpm
1080 - 1150
1080 - 1150
1080 - 1150
Maximum EGT – at cruise Rpm
1330
1330
1330
Operating EGT – at cruise Rpm
1180-1250
1180-1250
1180-1250
At time of maintenance, checks, if any item or system is found not to be in top condition, repair or replace the
item as appropriate.
If operated in dusty or sandy conditions, these inspections and maintenance procedures need to be performed
more frequently than listed.
When a gasket is removed, it must be replaced and the bolts must be re-torqued after 2 hours of operation.