Difference between revisions of "Honda RC149"

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[[Image:Honda-RC143-riden-by-Suiss-rider-Luigi-Tatcri.jpg|right|300px|thumb|Honda RC143 ridden by Suiss rider Luigi Tatcri]]
[[Image:Honda-RC143-riden-by-Suiss-rider-Luigi-Tatcri.jpg|right|300px|thumb|Honda RC143 ridden by Swiss rider Luigi Taveri]]
In the Sixties, the Japanese factories, bent on the conquest of Europe, launched themselves into a crazy technological scramble for the winner's circle in the world racing championship.
==Champion of the Four-Stroke==
Until the ban in 1967 on 50cc and 125cc engines with more than two cylinders and more than four cylinders in the larger displacements, Honda championed the four-stroke engine, which used extra cylinders to make up for the power it lost to two-stroke models. The error of this approach was apparent in the 125cc class where [[Honda]], world champion with two and four-cylinder engines, competed against the increasingly potent two-stroke twins of Yamaha and Suzuki. The two-stroke cycles ruled the championships in 1965.
 
==Magnesium Marvel==
To counter this challenge, Honda engineer Irimajiri (designer of the marque's 50cc twins and its six-cylinder 250) created a five-cylinder four-stroke made entirely from magnesium, for 1966. This amazing feat of engineering had pistons just 35 mm in diameter and cranked out 23,000 rpm yet stalled below 17,000 rpm, forcing the rider to work the nine-speed transmission relentlessly to keep the engine running! The Honda 125 proved unbeatable in the hands of the talented Swiss cyclist Luigi Taveri, It would force [[Yamaha]], [[Suzuki]], and [[Kawasaki]] to go to four-cylinder two-strokes for the 1967 season.


The RC148, used in the GP of Japan 1965, had the same bore and stroke as the RC 114, 33 x 29 mm, but the new RC149 gets the same dimensions as the RC116: 35.5 x 25.14 mm.
The RC148, used in the GP of Japan 1965, had the same bore and stroke as the RC 114, 33 x 29 mm, but the new RC149 gets the same dimensions as the RC116: 35.5 x 25.14 mm.
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There's also an oil temperature gauge. The oil temperature is checked, and the coolers can be covered more or less to maintain the oil temperature within certain limits
There's also an oil temperature gauge. The oil temperature is checked, and the coolers can be covered more or less to maintain the oil temperature within certain limits


Power output is 38 bhp at 20,500 rpm. If you're surprised that this is not 21,500 rpm, just like the RC116 : the complicated crankshaft reduces the mechanical efficiency somewhat, which results in a slightly lower Pme of 15.5 kg/cm2 and a 1000 rpm lower engine speed for maximum power. The polyester petrol tank has an unpainted strip, to check the petrol level. See images at right.  
Power output is 38 bhp at 20,500 rpm. If you're surprised that this is not 21,500 rpm, just like the RC116 : the complicated crankshaft reduces the mechanical efficiency somewhat, which results in a slightly lower Pme of 15.5 kg/cm2 and a 1000 rpm lower engine speed for maximum power. The polyester petrol tank has an unpainted strip, to check the petrol level. See images at right.
 
 
In the Sixties, the Japanese factories, bent on the conquest of Europe, launched themselves into a crazy technological scramble for the winner's circle in the world racing championship.
==Champion of the Four-Stroke==
Until the ban in 1967 on 50cc and 125cc engines with more than two cylinders and more than four cylinders in the larger displacements, Honda championed the four-stroke engine, which used extra cylinders to make up for the power it lost to two-stroke models. The error of this approach was apparent in the 125cc class where [[Honda]], world champion with two and four-cylinder engines, competed against the increasingly potent two-stroke twins of Yamaha and Suzuki. The two-stroke cycles ruled the championships in 1965.
 
==Magnesium Marvel==
To counter this challenge, Honda engineer Irimajiri (designer of the marque's 50cc twins and its six-cylinder 250) created a five-cylinder four-stroke made entirely from magnesium, for 1966. This amazing feat of engineering had pistons just 35 mm in diameter and cranked out 23,000 rpm yet stalled below 17,000 rpm, forcing the rider to work the nine-speed transmission relentlessly to keep the engine running! The Honda 125 proved unbeatable in the hands of the talented Swiss cyclist Luigi Taveri, It would force [[Yamaha]], [[Suzuki]], and [[Kawasaki]] to go to four-cylinder two-strokes for the 1967 season.
 




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