Welcome to the 1970 Yamaha CT1B Forum. Feel free to post anything related to this model in the category. The factory Yamaha Paint color was called "Candy Green". The USA vin range was: CT1-010101 to 031460. Anything new, will be added to this section. If you see any errors, please contact me privately.

                     (Bike/photo Courtesy of Kurt Flash)

                     1970 Yamaha CT1B Specifications

            Model 1970 Yamaha CT1B

   Dimensions:

Overall Length 78 In. / 1,980MM

Overall Width 35.8 In. / 910MM

Overall Height 43.7 In. / 1,110MM

Wheelbase 50.8 In. / 1,290MM

Min. Ground Clearance 9.4 In. / 240MM

    Weight:

Gross 232 Lbs. / 105Kg

Net 214 Lbs. / 97Kg

   Performance:

Max, Speed 65 MPH / 105Km/h +

Fuel Consumption 117 MPG @ 31 MPH / 50Km @ 50Km/h

(On paved level roads)

Climbing Ability 32 Degree

Min. Turning Radius 74.8 In. / 1,900MM

Braking Distance 49 Ft. @ 31 MPH (15M @ 50Km/h)

   Engine:

Model CT1

Type 2 Stroke, Gasoline

Lubricating System Separate (Yamaha Autolube)

Cylinder Single, forward inclined 5 Port

Displacement 10.43 cu. in. (171cc)

Bore X Stroke 2.598 X 1.969 In. (66 X 50MM)

Compression Ratio 6.75:1

Max Power 15.6 BHP/7,000 RPM

Max Torque 11.9 Ft.-Lbs/1.65 Kg-m @ 5,500 RPM                        

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

Starting System Primary-Coupled Kick

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

NGK Spark Plug & Gap B-8E 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 .30UF

   Carburetor:

Type VM24SH

Main Jet # 150

Jet Needle 4D3-3

Air Jet -

Needle Jet N-8

Cut Away 2.0

Pilot Jet (#) 30

Air Screw (turns out) 1 1/2

Starter Jet (#) 40

Float Level 25.5MM

  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 .78 Qts

   Gear Box:

Type Constant Mesh, 5 Speed Forward

1st Gear teeth & Ratio 3.182 (35/11) 34.85

2nd Gear teeth & Ratio 2.000 (30/15) 21.90

3rd Gear teeth & Ratio 1.368 (26/19) 14.99

4th Gear teeth & Ratio 1.000 (23/23) 10.93

5th Gear teeth & Ratio 0.800 (20/25) 8.76

Secondary reduction system Chain

Secondary reduction ratio 2.812 (45/16)

  Chassis:

Frame Tubular-Double Loop

Front Suspension System Front Telescopic fork

Rear Suspension System Swinging Arm

Fork Oil Capacity 150cc (5.1 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 Degrees

Trail 4.8 In. / 123MM

  Braking System:

Type of brake Internal Expansion

Front Operation System Right hand operation

Rear Operation System Right foot operation

  Tire Size:

Front 3.25 - 18 - 4PR Trials Universal

Rear 3.50 - 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 F130-06

Manufacturer Hitachi Ltd.

  Battery:

Model MV1-6

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

  Tanks:

Gasoline Tank Capacity 1.9 Gallons

Oil Tank Capacity 1.3 Quarts

  Chain:

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

The 1970 Yamaha CT1B Rider's Manual is Located: CLICK HERE

The 1970 Yamaha CT1B Service Manual is Located: CLICK HERE

The 1969-1971 Yamaha AT/CT Combined Service Manual is Located: CLICK HERE

The 1970 Yamaha CT1-B Parts Manual is located: CLICK HERE

The 1969-1971 Yamaha AT/CT Parts Manual is Located: CLICK HER

The 1970 Yamaha CT1B Advertisement # 1 is Located: CLICK HERE

The 1970 Yamaha CT1B Article # 2 is Located: CLICK HERE

The 1970 Yamaha CT1B Article # 2 is Located: CLICK HERE

The 1970 Yamaha CT1B Article # 3 is Located: CLICK HERE

The 1970 Yamaha CT1B Article # 4 is Located: CLICK HERE

The 1970 Yamaha CT1B Article # 5 is Located: CLICK HERE

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

The USA 1970 Yamaha CT1B Brochure is Located: CLICK HERE

The Canada 1970 Yamaha CT1B Brochure is Located: CLICK HERE

The 1970 Yamaha CT1-B Crankshaft Data is Located: CLICK HERE

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

The 1970 Yamaha Enduro Full Line Up Brochure 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 CT1-B Line-Up Advertisement # 2 is Located: CLICK HERE

The 1970 Yamaha CT1B Parts Store is Located: CLICK HERE