Welcome to the 1971 Yamaha JT1 Forum. The factory Yamaha color was called "Desert Orange". The USA Vin Range was JT1-000101 to 041708. Feel free to post anything related to this model in the category. Anything new, will be added to this section. If you see any errors, please contact me privately.
1972 Yamaha JT1
Model 1971 Yamaha JT1
Dimensions:
Overall Length 62 In. / 1,574MM
Overall Width 27.6 In. / 700MM
Overall Height 36.6 In. / 930MM
Wheelbase 41.5 In. / 1,055 MM
Min. Ground Clearance 6.3 In. / 160MM
Weight:
Gross 132 LBS / 60KG
Net -
Performance:
Max, Speed -
Fuel Consumption 176 mpg @ 19MPH
(On paved level roads)
Climbing Ability 22 degrees
Min. Turning Radius 59.1 In. / 1500MM
Braking Distance 24.6 Ft. @ 22 MPH (7.5M @ 35Km/h)
Engine:
Model JT1
Type 2 Stroke, Gasoline
Lubricating System Separate (Yamaha Autolube)
Cylinder Single, forward inclined 5 Port
Displacement 3.54 cu. in. (58cc)
Bore X Stroke 1.654 X 1.654 In. (42MM X 42MM)
Compression Ratio 6.4:1
Max Power 4.5 BHP/7,500 RPM
Max Torque 3.62 Ft.-Lbs @ 5,500 RPM
Piston Skirt Clearance .0016 - .0018 In. / 0.40 - 0.45MM
Starting System Primary-Coupled Kick
Ignition Timing B.T.D.C 1.8 MM
NGK Spark Plug & Gap B-7HS 0.5 MM (0.023 in)
Contact Break Point Gap 0.012 - 0.015 Inch / 0.3 - 0.4 MM
Volt Reg. Adjustment -
(Volts @ RPM - No load)
Cutout Relay Adjustment -
Condenser Capacity .22UF (Microfarad)
Carburetor:
Type Y16P Teikei / ID 288E1
Main Jet # 86
Jet Needle /Clip position 032-2
Air Jet -
Needle Jet 2.085
Cut Away 1.5
Pilot Jet (#) 38
Air Screw (turns out) 1 1/2
Starter Jet (#) 50
Float Level -
Intake:
Air Cleaner Wet, Foam Rubber
Transmission:
Clutch Wet, Multiple Disk
Primary reduction system Helical Gear
Primary reduction ratio 3.895 / (74/19) Teeth
Trans Oil Capacity .085 Quarts / 800 - 850cc
Gear Box:
Type Constant Mesh, 4 Speed Forward
1st Gear teeth & Ratio 3.077 (40/13) (reduction 37.7)
2nd Gear teeth & Ratio 1.889 (34/18) (reduction 23.1)
3rd Gear teeth & Ratio 1.304 (30/23) (reduction 16.0)
4th Gear teeth & Ratio 1.038 (27/26) (reduction 12.1)
5th Gear teeth & Ratio -
Secondary reduction system Chain
Secondary reduction ratio 3.153 (41/13)
Chassis:
Frame Tubular-Double Loop
Front Suspension System Front Telescopic fork
Rear Suspension System Swinging Arm
Fork Oil Capacity (R) 97cc (3.3 once) (L) 120cc (4.1 once)
Front Cushion System Coil Spring / Oil Damper
Rear Cushion System Coil Spring / Oil Damper
Steering System:
Steering Angle 47 Degrees both left & right
Caster 63.5 Degrees
Trail 2.7 In. / 68MM
Braking System:
Type of brake Internal Expansion
Front Operation System Right hand operation
Rear Operation System Right foot operation
Tire Size:
Front 2.50 - 15 - 4PR Trials Universal
Rear 2.50 - 15 - 4PR Trials Universal
Front Tire Pressure 22.4 P.S.I
Rear Tire Pressure 28 P.S.I
Oil Pump:
Adjustment Stroke Min 0.20 - 0.25 MM
Adjustment Stroke Max 1.85 - 2.05 MM
Dynamo:
Model F11-L46
Manufacturer Hitachi Ltd.
Battery:
Model -
Manufacturer -
Capacity -
Lighting:
Head Light -
Tail Light -
Stop Light -
Meter Light -
High Beam Indicator Light -
Tanks:
Gasoline Tank Capacity 1.13 Gallons (4.3 Liters)
Oil Tank Capacity 1.0 Quarts (1.0 Liters)
Chain:
Tension (Up & down free play) 25MM
The 1971 Yamaha JT1 Owner's Manual is located: CLICK HERE
The 1971 Yamaha JT1 Service Manual is Located: CLICK HERE
The 1971 Yamaha JT1 Combined Service Manual is Located: CLICK HERE
The 1971 Yamaha JT1 Assembly Manual is located: CLICK HERE
The 1971 Yamaha JT1 Parts Manual is located: CLICK HERE
The 1971 Yamaha JT1 racing information is Located: CLICK HERE
The 1971 Yamaha JT1 advertisement is located: CLICK HERE
The 1971 Yamaha JT1 advertisement 2 is located: CLICK HERE
The 1971 Yamaha JT1 advertisement 3 is located: CLICK HERE
The 1971 Yamaha JT1 advertisement 4 is located: CLICK HERE
The 1971 Yamaha JT1 article is located: CLICK HERE
The 1971 Yamaha JT1 article 2 is located: CLICK HERE
The 1971 Yamaha JT1 horse power modifications article is located: CLICK HERE
The Australia 1971 Yamaha JT1 article is located: CLICK HERE
The 1971 Yamaha JT1 Lighting kit information is located: CLICK HERE
The 1971 Yamaha JT1 autolube output color code is located: CLICK HERE
The 1971 Yamaha JT1 rotary valve installation (timing) is located: CLICK HERE
The 1971 Yamaha line up flyer is located: CLICK HERE
The 1971 USA Yamaha full Line Up Brochure is Located: CLICK HERE
The USA 1971 Yamaha JT1 Brochure is Located: CLICK HERE
The 1971 Yamaha JT1 Dealership poster is located: CLICK HERE