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1971 Yamaha HT1B

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Welcome to the 1971 Yamaha HT1-B Forum. Feel free to post anything related to this model in the category. The Factory color was called Metallic Purple. The USA vin range was HT1-215101 to 229459. Anything new, will be added to this section. If you see any errors, please contact me privately.


                     1971 Yamaha HT1-B Specifications


 

            Model 1971 Yamaha HT1B

 

   Dimensions:

 

Overall Length 73.8 In. / 1,875MM

 

Overall Width 35.4 In. / 900MM

 

Overall Height 40.7 In. / 1,035MM

 

Wheelbase 48 In. / 1,220MM

 

Min. Ground Clearance 8.9 In. / 225MM

 

    Weight:

 

Gross 201 Lbs. / 90Kg

 

Net 190 Lbs. / 90Kg

 

   Performance:

 

Max, Speed 55 MPH / 95Km/h

 

Fuel Consumption 164.5 MPG @ 25 MPH / 70Km @ 40Km/h

(On paved level roads)

 

Climbing Ability 25 Degree

 

Min. Turning Radius 68.9 In. / 1,750MM

 

Braking Distance 23 Ft. @ 22 MPH (7M @ 35Km/h)

 

   Engine:

 

Model HT1

 

Type 2 Stroke, Gasoline

 

Lubricating System Separate (Yamaha Autolube)

 

Cylinder Single, forward inclined 5 Port

 

Displacement 5.43 cu. in. (89cc)

 

Bore X Stroke 1.969 X 1.795 In. (50 X 45.6MM)

 

Compression Ratio 6.8:1

 

Max Power 8.5 BHP/7,000 RPM

 

Max Torque 6.51 Ft.-Lbs @ 6,500 RPM                        

 

Piston Skirt Clearance .0016 - .0018 In. / 0.40 - 0.45MM                                         

 

Starting System Primary-Coupled Kick

 

Ignition Timing B.T.D.C 1.8MM +/- .1MM

 

NGK Spark Plug & Gap B-7H 0.5-0.6 MM

 

Contact Break Point Gap 0.012 - 0.015 Inch / 0.30 - 0.4 MM

 

Fuse 10Amp X 2

 

Condenser Capacity .22UF (Microfarad)

 

   Carburetor:

 

Type VM20SC

 

Main Jet # 85

 

Jet Needle 4D3-3

 

Air Jet -

 

Needle Jet N - 6

 

Cut Away 2.0

 

Pilot Jet (#) 30

 

Air Screw (turns out) 1 3/4

 

Starter Jet (#) 40

 

Float Level 22.5MM

 

Idle Speed 1350 - 1450 RPM

 

  Intake:

 

Air Cleaner Wet, Foam Rubber

 

   Transmission:

 

Clutch Wet, Multiple Disk

 

Primary reduction system Helical Gear

 

Primary reduction ratio 3.894 / (74/19) Teeth

 

Trans Oil Capacity 650 - 700cc / .69 - 0.79 Qts

 

   Gear Box:

 

Type Constant Mesh, 5 Speed Forward

 

1st Gear teeth & Ratio 3.182 (35/11) 43.373

 

2nd Gear teeth & Ratio 2.000 (30/15) 27.263

 

3rd Gear teeth & Ratio 1.368 (26/19) 18.653

 

4th Gear teeth & Ratio 1.000 (23/23) 13.631

 

5th Gear teeth & Ratio 0.800 (20/25) 10.905

 

Secondary reduction system Chain

 

Secondary reduction ratio 3.500 (49/14)

 

  Chassis:

 

Frame Tubular-Double Loop

 

Front Suspension System Front Telescopic fork

 

Rear Suspension System Swinging Arm

 

Fork Oil Capacity 132cc - 147cc (4.5 - 5.0 Oz.)

 

Front Cushion System Coil Spring / Oil Damper

 

Rear Cushion System Coil Spring / Oil Damper

 

  Steering System:

 

Steering Angle 49 Degrees both left & right

 

Caster 60.5 Degrees

 

Trail 4.3 In. / 110MM

 

  Braking System:

 

Type of brake Internal Expansion

 

Front Operation System Right hand operation

 

Rear Operation System Right foot operation

 

  Tire Size:

 

Front 2.75 - 18 - 4PR Trials Universal

 

Rear 3.00 - 18 - 4PR Trials Universal

 

Front Tire Pressure 14 P.S.I

 

Rear Tire Pressure 17 P.S.I

 

  Oil Pump:

 

Adjustment Stroke Min 0.20 - 0.25 MM

 

Adjustment Stroke Max 1.85 - 2.05 MM

 

  Dynamo:

 

Model F130-07

 

Manufacturer Hitachi Ltd.

 

  Battery:

 

Model 6N2-2A-3

 

Manufacturer Furukawa Battery

 

Capacity 6V 2AH

 

 Lighting:

 

Head Light 6V 25W/25W

 

Tail Light 6V 5.3W

 

Stop Light 6V 17W

 

Meter Light 6V 3W X 2

 

High Beam Indicator Light 6V 1.5W

 

Flasher Light 6V 17W

 

  Tanks:

 

Gasoline Tank Capacity 1.7 Gallons (6.5 Liters)

 

Oil Tank Capacity 1.3 Quarts (1.2 Liters)

 

  Chain:

 

Tension (Up & down free play) 20MM (25/32)

 

The 1971 Yamaha HT1B Rider's Manual is Located: CLICK HERE

The 1971 Yamaha HT1B Rider's Manual 2nd edition is located: CLICK HERE

1971 Yamaha HT1B Service Manual

The 1971 Yamaha HT1B Service Manual located: CLICK HERE

1971 Yamaha HT1-B Parts Manual Supplement

The 1971 Yamaha HT1B Parts Manual Supplement is Located: CLICK HERE

The Primary HT1 Parts Manual is Located: CLICK HERE


The 1971 Yamaha HT1B Article is Located: CLICK HERE


The 1969-1971 Yamaha Autolube Adjustment & Color Codes are Located: CLICK HERE


1971 Yamaha HT1B Brochure

The 1971 Yamaha HT1-B Brochure is Located: CLICK HERE


The 1971 Yamaha HT1-B Factory Dealership Poster is Located: CLICK HERE


1971 Yamaha Full Line Up Brochure: CLICK HERE

The 1971 USA Yamaha Enduro Line Up Brochure is Located: CLICK HERE

The Germany 1971 Yamaha Line Up Brochure is Located: CLICK HERE

The Canada 1971 Yamaha Line Up Brochure is located: CLICK HERE

1971 Yamaha HT1B Advertisement

The 1971 Yamaha HT1B Advertisement is Located: CLICK HERE


The 1971 Motorcycle & Trail Bike Handbook is located: CLICK HERE

The 1971 Yamaha HT1B Store is Located: CLICK HERE

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