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Welcome to the 1971 Yamaha DT1MX Forum. 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. There were many errors, in the early Yamaha literature. I will make some error's of my own.
1970 Yamaha DT1MX Specifications
Model 1971 Yamaha DT1MX
Dimensions:
Overall Length 81.1 In. / 2,060MM
Overall Width 35.0 In. / 890MM
Overall Height 44.5 In. / 1,130MM
Wheelbase 53.6 In. / 1,360MM
Min. Ground Clearance 9.6 In. / 245MM
Weight:
Gross 256 Lbs.
Net 232 Lbs.
Performance:
Max, Speed -
Fuel Consumption -
(On paved level roads)
Climbing Ability 35 Degree
Min. Turning Radius 82.6 In. / 2,100MM
Braking Distance 40 Ft. @ 30 MPH (12.5M @ 50Km/h)
Engine:
Model DT1
Type 2 Stroke, Gasoline
Lubricating System Separate (Yamaha Autolube)
Cylinder Single, forward inclined 5 Port
Displacement 15 cu. in. (246cc)
Bore X Stroke 2.77 X 2.52 In. (70MM X 64MM)
Compression Ratio 8.2:1
Max Power 30 BHP/7,000 RPM
Max Torque 22.4 Ft.-Lbs @ 6,500 RPM
Piston Skirt Clearance .0018 - .0020 In. / 0.45 - 0.50MM
Starting System Primary-Coupled Kick
Ignition Timing B.T.D.C 2.3 MM +/- .011 - 0.13 MM
NGK Spark Plug & Gap B-10E (N) 0.5-0.6 MM
Contact Break Point Gap 0.012 - 0.015 Inch / 0.30 - 0.40 MM
Volt Reg. Adjustment -
(Volts @ RPM - No load)
Cutout Relay Adjustment -
Condenser Capacity .22UF (Microfarad)
Carburetor:
Type Mikuni VM30SH
Main Jet # 210 - 220
Jet Needle 5D5 - 4
Air Jet 0.5
Needle Jet 0 - 4
Cut Away 3.5
Pilot Jet (#) 80
Air Screw (turns out) 1 1/2
Starter Jet (#) 60
Float Level 25.5MM
Intake:
Air Cleaner Wet, Foam Rubber
Transmission:
Clutch Wet, Multiple Disk
Primary reduction system Helical Gear
Primary reduction ratio 3.095 / (65/21) Teeth
Trans Oil Capacity 1.06 Qts / 1,000cc
Gear Box:
Type Constant Mesh, 5 Speed Forward
1st Gear teeth & Ratio 2.250 (36/16) (21.888)
2nd Gear teeth & Ratio 1.650 (33/20) (16.051)
3rd Gear teeth & Ratio 1.261 (29/23) (12.267)
4th Gear teeth & Ratio 1.000 (26/26) (9.728)
5th Gear teeth & Ratio 0.793 (23/29) (7.714)
Secondary reduction system Chain
Secondary reduction ratio 3.143 (44/14)
Chassis:
Frame Tubular-Double Loop
Front Suspension System Front Telescopic fork
Rear Suspension System Swinging Arm
Fork Oil Capacity 210cc (7.1 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 5.12 In. / 130MM
Braking System:
Type of brake Internal Expansion
Front Operation System Right hand operation
Rear Operation System Right foot operation
Tire Size:
Front 2.75 - 21 - 4PR Knobby
Rear 4.00 - 18 - 4PR Knobby
Front Tire Pressure 13 P.S.I
Rear Tire Pressure 16 P.S.I
Oil Pump:
Adjustment Stroke Min 0.20 - 0.25 MM
Adjustment Stroke Max 1.85 - 2.05 MM
Dynamo:
Model FZA - 1BL
Manufacturer Mitsubishi Elec.
Battery:
Model -
Manufacturer -
Capacity -
Lighting:
Head Light -
Tail Light -
Stop Light -
Meter Light -
High Beam Indicator Light -
Tanks:
Gasoline Tank Capacity 2.5 Gallons
Oil Tank Capacity 1.7 Quarts
Chain:
Tension (Up & down free play) 20MM (25/32)
The 1971 Yamaha DT1E/DT1MX Rider's Manual is Located: CLICK HERE
The 1971 Yamaha DT1-MX Service Manual Supplement is Located: CLICK HERE
The 1968-1971 Yamaha DT1 Combined Service Manual is Located: CLICK HERE
The 1969-1971 Yamaha Autolube adjustment and Color Codes are Located: CLICK HERE
The 1971 Yamaha Full Line Up Brochure is Located: CLICK HERE
The 1971 Yamaha Motocross Full Line Up Brochure is Located: CLICK HERE
The 1971 Yamaha DT1-MX Store is Located: CLICK HERE
