Excelsior Twin
| In 1911, Ignaz Schwinn bought the Excelsior Motorcycle Company of Chicago, Illinois. His idea was that manufacturing bicycles and motorcycles would expand his empire and mutually benefit each other. Twenty years later, during the depression, he would close the doors of Excelsior, ending production of the third largest American motorcycle company. |
| The motorcycle you
will be looking
at came fitted with a special, "Big Valve Series 17 Ultra Power Twin,"
engine. You can detect this by the unusually large exhaust ports and
pipes.
When the owner found this machine it had a broken front exhaust port.
Unbelievably,
a new OEM cylinder was located. The engine displacement is 61 cubic
inches
or 996 cubic centimeters. It is classified as an IOE or intake over
exhaust
valve engine. The power rating is 20 h.p.. Excelsior designed
this
engine for racing.
In 1917 this motorcycle with a standard valve 61 cu.in. engine cost $265.00 without lights and horn, and $310.00 with. I have yet to find a price with lights, horn and racing engine. |
Click on the Photos to Enlarge.
 Here
is the owner doing a quick wipe down before the photo session. As you
can
see this is not far removed from the bicycle in its appearance. |
 You
can see the extra large exhaust pipes of this 61 cu.in. racing engine.
On this side and under the seat is the toolbox. |
|
 The
tires are Firestone's Non Skid tires. The tread is made up of the
words,
"NON" and "SKID," repeated over and over. I am not sure when these
tires
were molded but, they are not reproductions. Just above the
fender
is the front suspension spring. I read (but have not been able to
relocate
the article) that factory works riders pushed this model Excelsior up
to
128 mph. |
 Excelsior
used a unique rod and lever system instead of cable, to control the
throttle
and clutch. The clutch typically operated by the left foot pedal, can
be
locked in the disengaged position by the left handle bar grip. This
makes
it possible to stop on a hill and be able to put both feet down. The
right
grip is the throttle. On top of the dual compartment tank are two caps.
The front one is the oil cap and contains the lube oil auxiliary pump.
The back one is the gas cap and contains a pump which can be removed to
inject gas into the carburetor for cold starting. |
|
In front of the engine is the magneto ignition system. A Mitco mag with
lighting coils would recharge the battery and run lights. If there were
no lights or horn the mag was a Bosch. On the side of the tank is the
gear
shifter. The smaller lever on the side of the tank is the magneto
timing
advance control. Under the seat on this side is the battery
compartment.
The battery is a six volt wet cell. Beside this is the Kick starter.
This
kick starter is linked to a compression release to make starting
easier.
Above the mag are two oil control valves. The front valve and tube goes
to the oil pump on the other side of the engine case. The rear valve
stayed
closed until cruising above 45 mph. Then it was opened, followed by a
charge
from the hand pump (on top of the tank) and then closed again. The seat
post under the seat contains springs to ease the riders ride on bad
roads.
See the larger tube running between the lower vee of the cylinders and
dropping down the side of the engine case? It is the crankcase
ventilator.
Excelsior used the oil vapors to keep the primary chain lubricated. |
 The
cover at the bottom of the picture is the primary chain and clutch
cover.
This chain transfers the engine power to the transmission. A rod
connects
the transmission to the shifter on the side of the tank. In front of
the
primary chain cover is the clutch pedal. Beside that is part of the
linkage
from the clutch grip on the handle bar. The large silver item under the
tank is the carburetor. In the preceding picture you can see the float
bowl underneath. Beside the carburetor is the needle chamber. Just over
this is a small hard to notice lever. This lever opens a small port for
injecting gas into for cold starts. Why not just put the gas in the
throat
of the carb? Because, it contains a spring loaded one way disc valve;
sort
of like a reed valve only made of leather. My guess it is designed to
prevent
a backfire from burning the riders leg. The carb was manufactured
by Schebler. The opening below the carburetor throat is the float bowl
vent; designed to prevent a vacuum, from occurring in the float
chamber.
Notice the wires coming from the battery box. |
|
 Near
the upper left corner of the picture is a small cylindrical canister.
There
is also a twin on the other side. These are the dash pots for the seat
suspension. With pistons and springs they absorb and dampen road bumps
from the rear wheel. Most early motorcycle frames had no rear
suspension.
The rear hub has two brakes, an inner drum and outer band. The
inner
is the emergency brake controlled by depressing the clutch pedal fully.
It could then be locked on by the clutch grip on the handle bar. The
band
brake, used for normal stopping, is operated by the foot pedal on the
right
side of the motorcycle. Looking closely at the nickel plated part of
the
hub, you can see four of six cylindrical bulges. This is known as a,
"Kushion
Drive Sprocket." Inside the bulges are stiff springs, designed to
absorb
the shock of hard take-offs. You can see these in a couple of the other
pictures. |
 This
picture displays the position of the intake valves over the exhaust
valves.
The intake valve train had to be oiled occasionally by hand. In the
bottom
of the tank is a gas petcock. This can be used to prime the cylinders
via
the two tubes leading into the opposite ends of the intake manifold.
Notice
the manufactured indentations in the bottom of the tank for upper valve
clearance. In the top center of the timing gear case is a lever with a
rod running toward the rear. It is what operates the compression
release.
This connects to the kick start lever. When the kick starter is pushed
down, the exhaust valves are opened slightly to decompress the
cylinders,
making it easier to start. Directly behind the front exhaust pipe is
the
oil metering pump. It is supplied by the front valve on the other side
of the tank. This pump supplies the oil to all the bearings. Due to
inherent
oil starvation of the front piston and cylinder a tube and metering
valve
was provided, running from the bottom of the pump up to the base of the
cylinder wall. |
|
 The
front suspension consists of a set of links connected to the axle,
frame
and spring through various forks. The inner most forks connect to
the spring, whereas the other two go to the triple tree. The outer
struts
support the fender. Notice the small grease cups on the end of the
leading
links. |
 Here
is the remainder of the exhaust system; the muffler, tailpipe and
cutout.
The transmission is hidden in all the photos. But, it is worth
mentioning
that Excelsior advertised the transmission as an automotive type with
sliding
gears. Of course, all modern motorcycles standard transmissions are of
this type. |
|
 A
rider's view of the gear shifter, gear indicator plate and gas cap.
Just
in front of the shifter knob and down is the top of the spark advance
control
lever. On the right side is the top of the intake valve train of the
rear
cylinder. |
 What
you see here is the condition in which this motorcycle was found. As
sad
a state as this was, it still ran. I will never cease to be amazed by
the
transformation of this and so many other machines. From a mechanics
point
of view, it is a, "Labor of love." |
|
|
I hope you have enjoyed your visit here. If you did, be sure to recommend this site to your friends. And if you know someone who owns a business which would benefit from having a banner on this page, encourage them to contact me, the author at Ancient Alley . |
||
Thanks to:
The Owner of the machine in
the photos
The Illustrated
Encyclopedia
of Motorcycles, edited
by Erwin Tragatsch
Inside American Motorcycling
by Harry V. Sucher
Schwinn Bicycle Company
http://www.schwinn.com/heritage/timeline.html
| Everything
in this section is copyrighted and protected by U.S. and International
Laws. Nothing may be copied, printed, etc. without written permission
from
Tazbat Publishing, a division of SJR Systems. For permissions contact
the Publisher
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