Yamaha R5-B 350
Yamaha R5-B 350 | |
Manufacturer | |
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Production | 1971 |
Engine | Piston port two stroke, parallel twin cylinder. |
Compression ratio | 7.5:1 |
Top Speed | 153 km/h / 95 mph |
Ignition | Battery, dual coils, breaker points |
Transmission | 5 Speed |
Frame | Duplex cradle frame |
Suspension | Front: Telescopic fork Rear: Swingarm |
Brakes | Front: Drum, twin leading shoe Rear: Drum, single leading shoe |
Front Tire | 3.00-18 |
Rear Tire | 3.50-18 |
Wheelbase | 1341 mm / 52.8" |
Seat Height | 790 mm / 31.1" |
Weight | 146 kg / 322 lbs (dry), 154 kg / 340 lbs (wet) |
Oil Capacity | 2.0 L / 4.2 US pts |
Recommended Oil | Yamalube 10w-40 |
Fuel Capacity | 12 L / 3.2 US gal |
Manuals | Service Manual |
It could reach a top speed of 153 km/h / 95 mph.
Engine[edit | edit source]
The engine was a Air cooled cooled Piston port two stroke, parallel twin cylinder.. The engine featured a 7.5:1 compression ratio.
Drive[edit | edit source]
Power was moderated via the Multi-plate, wet.
Chassis[edit | edit source]
It came with a 3.00-18 front tire and a 3.50-18 rear tire. Stopping was achieved via Drum, twin leading shoe in the front and a Drum, single leading shoe in the rear. The front suspension was a Telescopic fork while the rear was equipped with a Swingarm. The R5-B 350 was fitted with a 12 L / 3.2 US gal fuel tank. The bike weighed just 146 kg / 322 lbs. The wheelbase was 1341 mm / 52.8" long.
Photos[edit | edit source]
Overview[edit | edit source]
Yamaha R5-B 350
Try to find a 350cc or smaller streetbike today like the Yamaha R5 350 Twin
and youll discover the pickins 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 wont
find a single 350cc or smaller machine carrying the Tuning Fork logo.
The 21-inchers
That wasnt 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 motorcyclists 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 wasnt 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 Yamahas continuing 2-stroke program. While it put out the same 36hp as the previous years 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 R5s low-speed engine performance.
Make Model | Yamaha R5-B 350 |
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Year | 1971 |
Engine/frame Numbers | R5-015101 - 042209 |
Engine Type | Piston port two stroke, parallel twin cylinder. |
Displacement | 347 cc / 21.2 cu in |
Bore X Stroke | 64 х 54 mm |
Compression | 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 Tire | 3.00-18 |
Rear Tire | 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 |