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Yamaha R5-A 350

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Make Model

Yamaha R5-A 350

Year

1970

Engine/frame Numbers

R5-000101 - 013649

Engine

Piston port two stroke, parallel twin cylinder.

Capacity

347 cc / 21.2 cu in
Bore x Stroke 64 х 54 mm
Compression Ratio 7.5:1
Cooling System Air cooled
Oil System Oil injection

Induction

2 x Mikuni VM28 SC carburetors

Ignition

Battery, dual coils, breaker points

Starting

Kick

Max Power

26.8 kW / 36 hp @ 7000 rpm

Max Torque

37.9 Nm / 3.87 kgf-m / 28 ft-lb @ 6500 rpm

Clutch

Multi-plate, wet

Transmission

5 Speed

Final Drive

Chain
Gear Ratios 1st 19.57 / 2nd 12.15 / 3rd 9.12 / 4th 7.38 / 5th 6.16:1
Frame Duplex cradle frame

Front Suspension

Telescopic fork

Rear Suspension

Swingarm

Front Brakes

Drum, twin leading shoe

Rear Brakes

Drum, single leading shoe

Front Tyre

3.00-18

Rear Tyre

3.50-18

Dimensions

Width: 739 mm / 29.1"

Wheelbase

1341 mm / 52.8"

Seat Height

790 mm / 31.1"

Footpeg Height

234 mm / 9.2"

Ground Clearance

180 mm / 7.1"

Dry Weight

146 kg / 322 lbs

Wet Weight

154 kg / 340 lbs

Oil Capacity 

2.0 L / 4.2 US pts

Fuel Capacity 

12 L / 3.2 US gal

Average Fuel Consumption

6.7 L/100 km / 14.9 km/l / 35 US mpg

Braking 48 km/h / 30 mph - 0

11 m / 36 ft

Braking 97 km/h / 60 mph - 0

37 km/ 121 ft

Standing ¼ Mile

15.5 sec / 130 km/h / 81 mph

Top Speed

153 km/h / 95 mph

Source

Motorcycle Classics

Try to find a 350cc or smaller streetbike today like the Yamaha R5 350 Twin and you’ll discover the pickin’s are slim. Honda has only one, the 234cc Nighthawk; Kawasaki two, the 124cc Eliminator 125 and the 249cc Ninja 250R; Suzuki two, the 249cc retro-style TU250X and cruiser-styled GZ250. And Yamaha? Ignoring the 249cc V-twin cruiser in its new Star Motorcycle line, you won’t find a single 350cc or smaller machine carrying the Tuning Fork logo.
The 21-inchers

That wasn’t the case back in the early 1970s, when small-bore bikes still ruled and the so-called 21-inchers (350cc = 21.35ci, hence the 21-inchers moniker) were among the hottest contenders for the motorcyclist’s dollar. Besides a smorgasbord of small-bore bikes from Italy, England and Germany, there was a full plate of small bikes available from Japan, including Yamaha.

By 1970, Yamaha had emerged as one of the leading Japanese motorcycle makers, behind Honda but ahead of Kawasaki and Suzuki. While Honda continued to embrace the 4-stroke ideal, Yamaha, like its other Rising Sun rivals, was still putting most of its faith in 2-stroke technology.

Despite the introduction of its first-ever 4-stroke, the 650cc parallel twin Yamaha XS-1, Yamaha wasn’t about to walk away from its 2-stroke twins and singles, which had brought Yamaha success in the consumer marketplace and on the track, and Yamaha knew there was still a lot of performance — and dollars — to wring out of its smaller bikes.

Yamaha had introduced its first “big” 2-stroke, the 305cc Big Bear, in 1966. That was followed a year later with the all new YR1 Grand Prix, whose short-stroke 348cc twin benefited heavily from lessons learned on the track, and finally, in 1970, the YR5, or the Yamaha R5 350 as it was known in the states.

The Yamaha R5 350 was in many respects the crown jewel of Yamaha’s continuing 2-stroke program. While it put out the same 36hp as the previous year’s twin, an increase in torque and other refinements meant it easily boasted the best performance of any 2-stroke Yamaha had ever made.

Where previous Yamaha 2-stroke twins had been very peaky, with a narrow power band ushering in a rush of acceleration at high revs but leaving engine response flat at lower engine speeds, the R5 could deliver usable power from as low as 3,000rpm, with peak torque of 28ft/lb developed at 6,500rpm. For the average rider, this was a huge improvement. Gone were the days of having to rev the engine to a scream before slipping the clutch to achieve any sort of smooth, low-speed take-off — or to pull cleanly once on the move. “The R5 pulls like a 500 when you twist the grip in fifth,” said Cycle World in appreciation of the R5’s low-speed engine performance.