For a bike so close in spirit to mopeds, I've found very little info specific to RD60s compiled here or elsewhere. Even the British wizards at the Yamaha Aircooled RD Club don't seem to be interested in anything much smaller than the RD200.
The Yamaha RD60 is a 55cc, single cylinder, two stroke, street motorcycle manufactured by Yamaha and imported from 1973 through 1975. The RD60 was the junior member of the Yamaha RD Series. It has an Autolube oiling system, which is an oil pump that is actuated by the throttle cable. Mine gave out on me at about 50 MPH and 9000 RPMs, so now I just premix. It is also "Torque Inducted" (uses reeds).
Weight: 163 Lbs.
Maximum speed: 53 MPH
Bore and stroke: 42 x 39.7 mm
Compression ratio: 6.9:1
Width: 24.8 "
Wheel Base: 46.7"
Fuel Capacity: 2.1 Gallons
Autolube oil capacity 1.1 quart.
Tire Size: 2:50 x 17 Both front and rear.
Maintenance and Repair
-The RD50 and 60 have nearly interchangeable parts, and Blake of Doscycles confirms that the DT50 MX has a similar bottom end.
There are also many parts that overlap with the GT50 and GT80, as well as the YZ series. YMMV.
Will upload wiring diagram and choice pages of the shop manual in the coming days.
-Treatland has a small section of upgrades.
-Additionally, Dos has this Athena kit.
At some point, Homoet made a clear-coat pipe that looks pretty nice.
Stock carburetor is a bolt-on Mikuni VM18.