1982-1983 Honda V45 Magna

The Honda V45 Magna was the motorcycle everybody else was afraid Honda might build someday.

| May/June 2016

  • 1982-1983 Honda V45 Magna
    Motorcycle Classics archives
  • 1980-1983 Kawasaki KZ750 LTD
    Photo courtesy investment-bikes.com
  • 1982-1983 Yamaha 750 Maxim
    Photo courtesy investment-bikes.com

Honda V45 Magna
Years produced:
80.3hp @ 9,500rpm (claimed)
Top speed:
147mph (period test)
748cc liquid-cooled DOHC 16-valve 90-degree V4
6-speed, shaft final drive
518lb (w/half tank fuel)/45-50mpg
Price then/now:
$3,298 (1982)/$1,500-$3,000

By the end of the 1970s, every Big Four bike maker built a “Universal Japanese Motorcycle,” an across-the-frame inline four — the format Honda pioneered in 1969 with the CB750 Four.

Not surprisingly, Big Red threw down the gauntlet once more at the start of the 1980s with another technological tour de force, the 1982 V45 Sabre/Magna. Said Cycle magazine in its May 1982 issue: “This is the motorcycle everybody else was afraid Honda might build someday.” While the Sabre was meant to satisfy the sporting rider, it was the “custom” Magna that captured the zeitgeist. Upright riding, stepped seats and laid-back bars were the fashion, and the Magna checked all those boxes.

The 90-degree V4 engine used four overhead camshafts, each pair spun by a “silent” chain with automatic tensioner. The cams worked forked rockers to operate the 16 valves in pairs. Four 32mm Keihin CV carbs (two down draft and two side draft to suit the V4’s orientation in the frame) fed the cylinders. Pistons ran in steel liners driving a compact crankshaft with four main and two big end bearings, each journal supporting two connecting rods side by side and spaced at 360 degrees. Drive to the 6-speed transmission was by straight-cut gears, with the clutch sprocket made up of two narrow gears running side by side, one loaded by the clutch shock absorber. The result: gear lash — and therefore whine — was virtually eliminated.

Using four valves with a narrow included angle and “squish-band” combustion chambers offered greater intake efficiency and provided better detonation resistance so a higher compression ratio could be used for more power. Combined with a short stroke to allow more revs at lower piston speeds and liquid cooling to maintain optimum operating temperature, the 750cc engine produced more than 80 horsepower at 9,500rpm.

Praising the technical sophistication of the Magna, Kevin Cameron reported in Cycle that it “is the first to combine all these things into one compact, powerful sporting unit that truly fits the engine space of a motorcycle,” opining that “…Honda has once again redefined the motorcycle.” Cycle World made some interesting comparisons with Honda’s own air-cooled inline engine, noting that while the Magna produced just 5 horsepower more, it did so with a much fatter torque curve and would run on 86 octane gas, while the inline engine, an older design, required 92 or more.

5/3/2016 5:40:51 AM

The only way a V45 Magna will go 147mph is if you kicked it out of the Space Shuttle's cargo bay. My Maxim X would take a V45's lunch every day, and on a good day, it might crack 130.

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