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

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
Copyright 2001 Tazbat Publishing

Most recent update 03.07.2004

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