Welcome to the 1970 Yamaha RT1M Forum. The factory paint color was called "Yamaha Black W/Yellow". The USA vin number range was: RT1 - 50101 to 52226. 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.

                  1970 Yamaha RT1M Specifications

            Model 1970 Yamaha RT1M

   Dimensions:

Overall Length 82.3 In.

Overall Width 35.0 In.

Overall Height 46.7 In.

Wheelbase 55.1 In.

Min. Ground Clearance 10 In.

    Weight:

Gross -

Net 238 Lbs.

   Performance:

Max, Speed -

Fuel Consumption -

(On paved level roads)

Climbing Ability 35 Degree

Min. Turning Radius 78.7 In.

Braking Distance 50.5 Ft. @ 31 MPH

   Engine:

Model RT1

Type 2 Stroke, Gasoline

Lubricating System Separate (Yamaha Autolube)

Cylinder Single, forward inclined 5 Port

Displacement 21.50 cu. in. (351cc)

Bore X Stroke 2.77 X 2.52 In. (80MM X 70MM)

Compression Ratio 7.5:1

Max Power 36 BHP/6,500 RPM

Max Torque 28.7 Ft.-Lbs @ 6,500 RPM                        

Piston Skirt Clearance .0022 - .0024 In. / 0.55 - 0.60MM                                         

Starting System Primary-Coupled Kick

Ignition Timing B.T.D.C 3.4 MM +/- .1 MM

NGK Spark Plug & Gap B-9EN (N) 0.5-0.6 MM

Contact Break Point Gap 0.011 - 0.013 Inch / 0.30 - 0.35 MM

Volt Reg. Adjustment -

(Volts @ RPM - No load)

Cutout Relay Adjustment -

Condenser Capacity .22UF (Microfarad)

   Carburetor:

Type Mikuni VM34SH

Main Jet # 280

Jet Needle 6DP1 - 3

Air Jet -

Needle Jet P - 0

Cut Away 1.5

Pilot Jet (#) 40

Air Screw (turns out) 1 1/4

Starter Jet (#) 60

Float Level 8.5 MM

  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) (19.425)

2nd Gear teeth & Ratio 1.650 (33/20) (14.979)

3rd Gear teeth & Ratio 1.261 (29/23) (11.838)

4th Gear teeth & Ratio 1.000 (26/26) (9.078)

5th Gear teeth & Ratio 0.793 (23/29) (7.199)

Secondary reduction system Chain

Secondary reduction ratio 2.933 (44/15)

  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 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 FZA - 1A1L

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 (9.5 Liters)

Oil Tank Capacity 1.7 Quarts (1.6 Liters)

  Chain:

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

The 1970 Yamaha RT1M Rider's Manual is Located: CLICK HERE

The 1970 Yamaha RT1M Combined Service Manual is Located: CLICK HERE

The 1970 Yamaha RT1-M Parts Manual is located: CLICK HERE

The 1969-1971 Yamaha Autolube adjustment and Color Codes are Located: CLICK HERE

The 1970 Yamaha Full Line Up Brochure is Located: CLICK HERE

The 1970 Yamaha Motocross Full Line Up Brochure is Located: CLICK HERE

The 1970 Yamaha RT1-M Crankshaft Data is Located: CLICK HERE

The 1970 Cycle Buyers Guide is Located: CLICK HERE

The 1970 Motorcycle & Trail Biking handbook is located: CLICK HERE

The 1970 Yamaha RT1-M Parts are Located: CLICK HERE