Table of Contents

IH: General Technical Information


1970 - 1977

1970 - 1977 Service Intervals

Regular Service Interval

GreaseOilService
Every 1000 Miles Rear Chain
  • Air Cleaner
  • Battery Rear
  • Rear Chain Adjustment
  • Gasoline Valve, lines and fittings
  • Check fastener tightness
Every 2000 Miles
  • Rear Brake Shaft
  • Front Brake Shaft
  • Rear Brake Cross-over Shaft (1974 & earlier)
  • Clutch Release Worm (1970)
  • Foot Shift Lever
  • Seat Bar Roller and Bolt
  • Kick Starter Shaft
  • Rear Wheel Hub
  • Speedometer Drive (1973 & later)
  • Foot Shift Crossover Shaft (1975-76)
  • Rear Brake Rod Clevis
  • Front Brake Cable Clevis
  • Clutch Hand Lever
  • Brake Hand Lever
  • Clutch Control Cable
  • Front Brake Cable
  • Throttle Control Cable
  • Seat Post (saddle only
  • Tappet Adjustment
  • Clutch Adjustment
  • Brake Adjustment
  • Oil Filter
  • Front Chain Adjustment
  • Rear Chain Oiler (1976 & earlier)
  • Circuit Breaker Points
Every 5000 Miles
  • Throttle Control Spiral
  • Circuit Breaker Camshaft
  • Front Wheel Hub (1964 & earlier)
  • Speedometer and Tachometer Cables
Every 10000 Miles
  • Repack Rear Fork Pivot Bearings
  • Repack Wheel Bearings
Weekly
  • Check Tires and Battery

1)

Service Interval Engine and Transmission

300 Miles1000 Miles2000 Miles5000 Miles or 1 YearSpring and Fall
Engine OilCheckCheckChange Change
Transmission Oil Check ChangeChange

2)

POC for this page — Bert Linson 2016/01/20 20:03

1970 - 1977 Sportster Fastener Torque Requirements

Chassis

  • Axle Nut: 50 ft-lbs / 67.79 Nm
  • Brake Disc Mounting Screw: 35 ft-lbs / 47.45 Nm (1973)
  • Brake Disc Mounting Screw: 10 ft-lbs / 13.5 Nm (1974 & later)
  • Fork Stem Pinch Bolt: 20 - 25 ft-lbs / 27.11 - 33.89 Nm
  • Handlebar Clamping Bolt: 20 ft-lbs / 27.11 Nm
  • Front Caliper Bolt: 35 ft-lbs / 47.45 Nm
  • Front Brake Disc Bolt: 35 ft-lbs / 47.45 Nm

Engine

  • Gear Shaft Nut: 100 - 120 ft-lbs / 135.6 - 162.7 Nm
  • Sprocket Shaft Nut: 100 - 120 ft-lbs / 135.6 - 162.7 Nm
  • Crank Pin Nut: 150 ft-lbs / 203.37 Nm
  • Rocker Arm Cover Screw: 20 ft-lbs / 27.11 Nm
  • Cylinder Head Bolt: 65 ft-lbs / 88.12 Nm
  • Carburetor (Tillotson) Inlet Seat Assembly: 40 - 45 in-lbs / 4.519 - 5.084 Nm
  • Carburetor (Tillotson) Accelerator Pump Channel Plug: 23 - 28 in-lbs / 2.598 - 3.163
  • Clutch Hub Nut (1971 & later): 150 ft-lbs / 203.37 Nm
  • Gear Cover Screws, Chain Cover Screws, and Oil Pump: 100 in-lbs / 11.298 Nm

Electrical

  • Spark Plug: 20 ft-lbs / 27.11 Nm
  • Starter Motor Thru Bolt (Prestolite): 20 - 25 in-lbs / 27.11 - 33.89 Nm
  • Starter Motor Thru Bolt (Hitachi): 20 - 25 in-lbs / 27.11 - 33.89 Nm

1970 - 1977 Sportster Engine Specifications

Valves

  • Fit in Guide (EX): .0025 - .0045 in
  • Fit in Guide (IN): .0015 - .0035 in
  • Spring (outer)
    • 55 - 66 lbs. @ 1-9/32 in. (valve closed)
    • 152 - 168 lbs. @ 15/16 in. (valve open)
  • Spring (inner)
    • 30 - 36 lbs. @ 1-3/32 in. (valve open)
    • 76 - 88 lbs. @ 3/4 in. (valve closed)
  • Spring free length:
    • 1-1/2 in. (outer)
    • 1-23/64 in. (inner)

Rocker Arm

  • Fit in bushing: .001 - .0025 in. Loose

Piston

  • Fit in cylinder: .003 - .004 in. loose
  • Ring Gap: .015 - .025 in.
  • Ring side clearance: .0035 - .005 in.
  • Piston pin fit: Light hand press fit at 70 degrees Fahrenheit.

Connecting Rod

  • Piston pin fit: .0008 - .001 in. loose
  • End play between flywheels: .005 - .001 in.
  • Fit on crank pin: .0005 - .001 in. loose

Oil Pump Pressure

At 60 MPH in high gear (oil hot).

  • Minimum: 10 lbs. / sq. in.
  • Maximum: 20 lbs. / sq. in.

Tappets

  • Guide fit: .0005 - .001 in. press
  • Fit in guide: .0005 - .001 in. loose
  • Roller fit: .0005 - .001 in.
  • Roller end clearance: .008 - .010 in.
  • Tappet clearance: Just free (no lash) - Engine cold

Cam Gear Timing

  • Intake
    • Opens: 79 - 85 degrees BTC
    • Closes 79 - 85 degrees ABC
  • Exhaust
    • Opens: 81 - 89 degrees BBC
    • Closes: 76 - 84 degrees ATC

Gearcase

  • Intermediate gear shaft
    • In bushing: .0005 - .001 in.
  • Cam gear shaft in bushing: .0005 - .002 in.
  • Cam gear shaft
    • In needle bearing: .0005 - .003 in.
  • Cam gear end play
    • 1976 & earlier: .001 - .005 in.
    • 1977 & later: .003 - .007 in.
  • Cam gear backlash: .000 - .0005 in.

Flywheel Assembly

  • Gear shaft nut torque: 150 ft-lbs
  • Sprocket shaft nut torque: 150 ft-lbs
  • Crank pin nuts torque: 150 ft-lbs
  • Runout (flywheels): .003 in. maximum at rim
  • Runout (main shafts): .002 in. maximum

Sprocket Shaft Bearing

  • Cup fit in crankshaft: .0005 - .0025 in. tight
  • Cone fit on shaft: .0002 - .0015 in. tight
  • End play: .001 - .007 in.

Pinion Shaft Bearing

  • Shaft fit in roller bearing: .0005 - .0015 in.
  • Shaft fit in cover bushing: .0005 - .0015 in.

Ignition Timing

  • Breaker point gap setting
    • 1970: .020 in.
    • 1971 & later: .018 in.
  • Dwell
    • 1970 & 1971: 90 degrees @ 2000 rpm
    • 1972 & later: 140 degrees @ 2000 rpm
  • Spark plug gap setting: .025 - .030 in.
  • Ignition timing - Advanced
    • 1971 & earlier: 45 degrees (11/16 in. BTC)
    • 1972 % later: 40 degrees (17/32 in. BTC)
  • Ignition timing - Retarded
    • 1971 & earlier: 15 degrees (5/64 in BTC)
    • 1972 & later: 10 degrees (1/32 in BTC)

1) , 2)
Harley Davidson 1970 - 1977 Service Manual
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