In the beginning came the Cub. Honda’s
most easily recognizable motorcycle
first hit the streets of the U.S. in 1958
and was an instant success, selling
24,000 units in its first five months.
And while the step-through, 3-speed
50cc Cub worked perfectly for urban
commuters, motorcycle enthusiasts,
especially in the U.S., wanted more.
Honda’s twin-cylinder range of CA
touring and CB sport bikes was well
established by 1964, but there was
room in the market for something
between the Cubs and the twins. Enter the Honda 90.
The first 90, the C200, arrived in 1963 with an iron cylinder
and head, pushrod valve operation and a conventional 4-speed
transmission instead of the Cub’s 3-speed automatic clutch unit.
It also looked more like a traditional motorcycle, though with a
pressed steel spine frame. Then in 1964 came the sporty S90 withan all-alloy engine and overhead camshaft.
Honda wasn’t the first motorcycle manufacturer to produce
street bikes with overhead camshaft engines, of course, but
Big Red did take them fully mainstream. The advantages of the
design — a lighter, more direct valve train — meant Honda’s
engines could be tuned for more power at higher revs, also mak-
ing them more efficient. The downside was
that overhead cam engines were typically
more expensive to manufacture and valve
clearances more difficult to adjust. Honda’s
innovative design used a single chain-driven
camshaft in the cylinder head operating the
valves by a pair of rockers. Each rocker had
a screw adjuster for straightforward valve
adjustment.
The S90’s “over-square” (50mm x 45.6mm
bore and stroke) 89.5cc engine was arranged
with its iron-lined alloy cylinder almost
horizontal, and capped with a light alloy
cylinder head containing the single cam-
shaft. The built-up crankshaft ran on two
impressively large ball main bearings with
a caged roller bearing big end. The “wet”
sump held a quart of oil, which it kept clean
with a centrifugal oil filter. Drive to the wet
mutliplate clutch was by gears, passing
from there to a 4-speed constant mesh gear-
box with left side foot control (one down,
three up). Final drive was by chain. Claimed
output was 8 horsepower at 9,500rpm — an
impressive rate compared with most of its
contemporaries.
The compact drivetrain was bolted to a
pressed steel beam frame. Front suspension
was by hydraulically damped telescopic fork,
with a swingarm with two spring/damper
units at the rear. The chassis ran on 18-inch
wheels front and rear, both with 2.50 x
18-inch tires and single-leading-shoe drumA few hours trolling online motorcycle market sites turned up a handful of S90s
for sale, including this example offered on Craigslist by a private seller in Greenbrae,
California, for $1,500. Found abandoned in a shed, it had been put back to running
condition, but not restored, and appeared to be mostly original, save for non-stock
handlebars and a non-stock air filter and throttle assembly, and some localized
repainting. The ancient tires would need replacement, but otherwise it looked like
a solid old S90 needing only a sympathetic owner to really make it shine. Sold
as a “daily rider,” it came with spare parts and a shop manual. It had its original
California black plate and a clear California title. If it was as advertised, someone got
a nice little S90 for what we think was a reasonable price.8 MOTORCYCLE CLASSICS September/October 2017
ON THE MARKET
1965 Honda S90/$1,
Honda’s Cammy Cub:
1964-
Honda S
UNDER THE
RADAR
MECUM AUCTIONS