Flat Head Specs

Basic Specs for single cylinder, aluminum block, flat head engines.
You may be more familiar with the term "side valve" or "L head" instead of "flat head". Aluminum blocks with steel sleeves are included here.
See the table following this one for "Cast Iron" block flat heads.
Some common specs where applicable.
Initial Carb Settings; High speed=1 1/2. Idle=1 1/4.
Ring gap reject size; Compression rings=.035"(Cast Iron=.030")
Oil ring=.045"(Cast Iron=.035")
Spark Plug gap=.030"
Points gap=.020"

Basic Model
Series Idle
Speed Armature
Air Gap Valve Clearance Torque
Specs

Intake Exhaust Flywheel
Nut Cylinder
Head Conn
Rod

60000 1750 .006"
.010" .005"
.007" .007"
.009" 55 ft
lbs 140
in lbs 100
in lbs

80000
81000
82000 1750 .006"
.010" .005"
.007" .007"
.009" 55 ft
lbs 140
in lbs 100
in lbs

90000
92000
93000
94000
95000 1750 .006"
.010" .005"
.007" .007"
.009" 55 ft
lbs 140
in lbs 100
in lbs

100200
100900 1750 .010"
.014" .005"
.007" .007"
.009" 60 ft
lbs 140
in lbs 100
in lbs

100700
10A900
10B900
10c900 1750 .006"
.010" .005"
.007" .007"
.009" 55 ft
lbs 140
in lbs 100
in lbs

120000 1750 .006"
.010" .005"
.007" .007"
.009" 55 ft
lbs 140
in lbs 100
in lbs

130000 1750 .010"
.014" .005"
.007" .009"
.011" 60 ft
lbs 140
in lbs 100
in lbs

170000 1750 .010"
.014" .005"
.007" .009"
.011" 65 ft
lbs 165
in lbs 165
in lbs

190000 1750 .010"
.014" .005"
.007" .009"
.011" 65 ft
lbs 165
in lbs 185
in lbs

220000 1750 .010"
.014" .005"
.007" .009"
.011" 65 ft
lbs 165
in lbs 185
in lbs

250000 1750 .010"
.014" .005"
.007" .009"
.011" 65 ft
lbs 165
in lbs 185
in lbs

280000
except
286700 1750 .010"
.014" .005"
.007" .009"
.011" 65 ft
lbs 165
in lbs refer to
manual

286700 1750 .010"
.014" .004"
.006" .009"
.011" 65 ft
lbs 165
in lbs refer
to manual

Flat Head Cast Iron Specs

Basic Model
Series Idle
Speed Armature
Air Gap Valve Clearance Torque
Specs

Intake Exhaust Flywheel
Nut Cylinder
Head Conn
Rod

230000 1200 .010"
.014" .007"
.009" .017"
.019" 145 ft
lbs 190
in lbs 190
in lbs

240000 1200 .010"
.014" .007"
.009" .017"
.019" 145 ft
lbs 190
in lbs 190
in lbs

300000 1200 .010"
.014" .007"
.009" .017"
.019" 145 ft
lbs 190
in lbs 190
in lbs

320000 1200 .010"
.014" .007"
.009" .017"
.019" 145 ft
lbs 190
in lbs 190
in lbs

Go To The Lawn Mower Repair Man's "Front Page"
Go to Single Cylinder OHV non Intek Specs
Go to Flathead Twin Specs
Go to Intek Single Cyl. OHV Specs
Go to Vanguard V-Twin OHV Specs

Basic Model Series	Idle Speed	Armature Air Gap	Valve Clearance		Torque Specs
			Intake	Exhaust	Flywheel Nut	Cylinder Head	Conn Rod
60000	1750	.006" .010"	.005" .007"	.007" .009"	55 ft lbs	140 in lbs	100 in lbs
80000 81000 82000	1750	.006" .010"	.005" .007"	.007" .009"	55 ft lbs	140 in lbs	100 in lbs
90000 92000 93000 94000 95000	1750	.006" .010"	.005" .007"	.007" .009"	55 ft lbs	140 in lbs	100 in lbs
100200 100900	1750	.010" .014"	.005" .007"	.007" .009"	60 ft lbs	140 in lbs	100 in lbs
100700 10A900 10B900 10c900	1750	.006" .010"	.005" .007"	.007" .009"	55 ft lbs	140 in lbs	100 in lbs
120000	1750	.006" .010"	.005" .007"	.007" .009"	55 ft lbs	140 in lbs	100 in lbs
130000	1750	.010" .014"	.005" .007"	.009" .011"	60 ft lbs	140 in lbs	100 in lbs
170000	1750	.010" .014"	.005" .007"	.009" .011"	65 ft lbs	165 in lbs	165 in lbs
190000	1750	.010" .014"	.005" .007"	.009" .011"	65 ft lbs	165 in lbs	185 in lbs
220000	1750	.010" .014"	.005" .007"	.009" .011"	65 ft lbs	165 in lbs	185 in lbs
250000	1750	.010" .014"	.005" .007"	.009" .011"	65 ft lbs	165 in lbs	185 in lbs
280000 except 286700	1750	.010" .014"	.005" .007"	.009" .011"	65 ft lbs	165 in lbs	refer to manual
286700	1750	.010" .014"	.004" .006"	.009" .011"	65 ft lbs	165 in lbs	refer to manual