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Difference between revisions of "Honda RC149"
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==Magnesium Marvel== | ==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. | 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 crankshaft has a special configuration: the three cylinder part has the crankpins at 120 degrees, the two cylinder part has the crankpins, in the usual Honda fashion, at 180 degrees. Both crankshaft are coupled together at the position of the camshaft drive. | |||
The valve angle is 56 degrees, 24 degrees for the inlet and 32 degrees for the exhaust valves. Lubrication system is by wet sump, with two oil coolers in the sides of the fairing. | |||
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. | |||
[[Category:Honda motorcycles|RC149]] | [[Category:Honda motorcycles|RC149]] | ||
[[Category:Honda RC series|RC149]] | [[Category:Honda RC series|RC149]] | ||