Table of Contents
IH: General Technical Information
1970 - 1977
1970 - 1977 Service Intervals
Regular Service Interval
Grease | Oil | Service | |
Every 1000 Miles | Rear Chain |
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Every 2000 Miles |
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Every 5000 Miles |
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Every 10000 Miles |
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Weekly |
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Service Interval Engine and Transmission
300 Miles | 1000 Miles | 2000 Miles | 5000 Miles or 1 Year | Spring and Fall | |
Engine Oil | Check | Check | Change | Change | |
Transmission Oil | Check | Change | Change |
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)