RD350 - RD350 Parts, Tuning & Performance, Downloads

Setting up RD350

 

 

YAMAHA ** Only AIRCooled Models
RD Models RD125 RD200 RD250 RD350

A/B

RD400
Pist. Side Clearance(in.)

 

0014-0016 0016-0018 0016-0018 0016-0018 0012-0014
Ring End Gap

(in)

 

0.008-0.016 0.006-0.014 0.006-0.014 0.008-0.016 0.012-0.020
Oil Pump-Min. Stroke(mm)

 

0.20-0.25 0.20-0.25 0.20-0.25 0.20-0.25 0.20-0.25
Compression

Ratio

 

7.1:1 N/A 6.6:1 6.6:1 6.2:1
Bore/Stroke  (mm) 52×46 N/A 54×54 64×54 64×62

 

Weight (Stock) LBS 256 N/A 309 315 342
Carb Type Tekiei-Y20P-1A N/A Mik.VM28SC Mik.VM28SC Mik.VM28SC

 

Main Jet 94 94 120 140(75=110) 115

 

Pilot Jet 44 44 30 25 25

 

Float Level

(mm)

20 20 15 15 23
Jet Needle 4D50-2 4F51-2 514-3 514-3 5L1-3

 

Needle Jet N30 N80 O-8 O-8 P-2

 

Air Screw Turns Out 1 1/2 1 1/4 1 1/4 1 3/4 1 1/4

 

Point Gap(mm) 0.30-0.40 0.30-0.40 0.30-0.40 0.30-0.40 0.30-0.40

 

 

More Details:

Specifications for a Yamaha RD350

By Chris Gilliland, eHow Contributor, last updated December 30, 2011

The RD350 is a 347cc air-cooled two-stroke motorcycle that was produced by the Yamaha Motor Corporation from 1973 to 1975. The RD350 has enjoyed tremendous success during its production years both as a street bike and a competent road racing machine. The motorcycle was eventually replaced in 1976 by a larger version, the RD400, before Yamaha retired the RD-series in 1979. With many well-kept examples available on the market today, an RD350 remains a popular choice for vintage motorcycle collectors and racers.

 

Frame and Suspension

The RD350 features a tubular steel duplex cradle frame, in which a pair of down tubes extends below the steering head and loops under the motor to create a cradle. Forward suspension was provided by a pair of 34mm telescopic forks while three-way adjustable twin shock-absorbers suspended the rear swing arm. For wheels, the RD350 was equipped with wire-spoked 3 x 18 inch front and 3.5 x 18 inch rear wheels. The steering head’s rake angle of 27.5 degrees and a generous 4.2 inch trail, combined with a wheel base of 52 inches, providing nimble, yet stable, handling characteristics.

Brakes

Unlike the previous Yamaha models, the RD350 was equipped with a front hydraulic disc-style brake. The dual piston caliper was mounted on the right fork and gripped a 267mm (10.51 inch) steel brake rotor. The caliper is actuated by a master cylinder on the right handlebar. A conventional 178mm (7 inch) single-leading-shoe drum brake was fitted to the rear wheel.

 

Motor and Transmission

The RD350 was powered by an air-cooled two-stroke parallel twin cylinder motor, which used a 34mm bore and 54mm stroke to create a displacement of 347cc. The motor was rated with a compression ratio of 6.6:1 and was claimed to create a maximum of 39 horsepower at 7,500 RPM. Unlike the previous two-stroke motors used on earlier Yamaha motorcycles, the RD350 implemented reed valves in the motor’s intake. These one-way reed valves prevented the mixture of air and fuel from being blown back out through the intake and widened the RD350’s powerband, the engine’s RPM range that provided the maximum amount of usable power. The motor transmitted power through a six gear, wet clutch transmission. The rear wheel was driven by a 92 link, 530 pitch drive chain turned by a 16 tooth front sprocket and a 40 tooth rear sprocket.

Fuel Systems

Fuel was held within a 3.2 gallon steel fuel tank and was fed to a pair of 28mm Mikuni VM carburetors. Two-stroke oil, which is typically pre-mixed into the fuel, was injected into the carburetor by Yamaha’s Autolube system, eliminating the need for messy pre-mixed fuels. The Autolube system was driven by the transmission’s input shaft and was fed by a separate oil tank.

Electrical Systems

The RD350 was powered by a 12 volt electrical system, drawing power from a 5.5 amp hour battery. A permanent magnet stator generated power while the motorcycle was in operation, recharging the battery. The motor’s ignition system is based on mechanical breaker points, which open at preset intervals and fire the ignition coils.The motorcycle was started by kick lever.

 

More To Remember:

 

Techincal Specifications of the Yamaha RD 350*:
dimensions:
Overall length
Overall width
Overall height
Wheelbase
Min. ground clearance
Weight(Dry)
:
:
:
:
:
:
2,040mm
835mm
1,110mm
1,320mm
155mm
143 kgs
performance:
Speed
Climbing ability
Braking distance
Min. turning radius
Acceleration performance(400m)
:
:
:
:
:
130 km/h max. (?150km/h)
28º
14m at 50 km/h
2,300mm
13.7 secs
engine:
Model
Type

Cylinders
Carburettors
Lubrication
Displacement
Bore and Stroke
Compression ratio
Maximum power
Maximum torque
Starting
Ignition
Air filter

:
:

:
:
:
:
:
:
:
:
:
:
:

1A1.51
2 stroke cycle, Air cooled gasoline, Torque Induction
Twin cylinders, forward inclined in parallel
Twin Mikuni VM-28
Autolube
347cc
64mm*54mm
6.6:1
30.5bhp@6,750rpm
3.3kg-m@6,500rpm
Kick starting
Battery ignition
Dry paper filter type
power transmission:
Clutch
Primary reduction system
Primary reduction ratio
Secondary reduction system
Secondary reduction ratio
Gear box
:
:

:
:

:

:

Wet, multi plate type
Helical gear drive

2.869:1 (66:23)
Chain sprocket

2.666:1 (40:15)

Constant mesh, 6 forward speed

gear ratios:
1st
2nd
3rd
4th
5th
6th
:
:
:
:
:
:
2.571:1 (36/14)
1.777:1 (32/18)
1.318:1 (29/22)
1.040:1 (26/25)
0.888:1 (24/27)
0.785:1 (22/28)
transmission oil:
Quantity
Type
:
:
1500cc +/- 50cc
SAE 10W/30SC
filling capacity:
Fuel tank

Oil tank

:

:

15.5ltrs (Petrol)
-3ltrs Reserve
-2ltrs Useable
2ltrs (Servo 2T Supreme)
frame:
Model
Type
:
:
1A1
Double cradle type
suspension:
Front
Rear
:
:
Telescopic Fork Oil Damped
Swing arm, Coil spring oil damper (Adjustable 3 position)
braking system:
Front
Rear
:
:
Internal Expansion Twin Leading type
Internal Expansion
tyres:
Front
Rear
:
:
3.00*18-4PR
3.50*18-4PR
generator:
Model
Manufacturer
Spark plug
Battery
Horn
:
:
:
:
:
AR 3345
Kokusan Denki, Japan
BP7HS-NGK or equivalent
12v 5.5AH
12v 2.5Amps
lights:
Head light
Tail light/ Stop light
Flasher lights
Neutral light
Meter lights
High Beam Indicator light
Flasher Pilot light
:
:
:
:
:
:

:

12V-35/35W
12V-8/27W
12V-27W*2
12V-2W
12V-2W*4
12V-2W

12V-2W

*All the data is from the workshop manual.

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