Wednesday, April 13, 2011


Shot ca.1930, when the Thor was last given an airing
With dozens of 'original paint board-track racers' crowding the auction houses of late, parsing the clever fakes and the Real Deal has become an exercise in suspicion, head-scratching, and a desperate search for printed history which is thin on the ground.  Months ago, Virgil Eling, director of the Solvang Vintage Motorcycle Museum, sent a note to The Vintagent; is there any extant literature on Board Track Racing single-cylinder Thors?  My silence on the subject (proving no info at hand) led to a conversation with Virgil at the Las Vegas auction week, the premier spot in the US for a moto-schmooze.
The Thor as it appears today; grungy and original - perfect!
The results of Eling's research are in the metal, and the museum: a ca.1913 Thor board-track single-cylinder racer, untouched since 1930.  It lived its whole life with one family, near Chicago, the location of the Aurora Machine and Tool Co, who built Thor motorcycles and supplied components to seemingly the whole of the nascent American motorcycle industry.  The anecdotal history of this machine claims it was raced until 1920, laid up as we see it, then brought out by the family ca. 1930 for some dirt-track practice and new tires fitted, but time had marched on in such racing, and the clutchless, throttle-less Thor single proved a handful, and it was laid up again, as we see it today, a fascinating relic.  Research has yet to show another single-cylinder racing machine from Thor of this era, although there are photos of an earlier Thor, ca.1908 and identical to an Indian 'Torpedo Tank' racer (below).
ca.1909 Thor racer, of the type used by Don Johns to win races in California...
Like most early motorcycle makers, the Thor has roots in the bicycle industry of the late 1800s.  The Aurora Machine and Tool Co was founded in 1886 to supply component parts of bicycles; frame lugs, wheel hubs, spoke nipples, handlebars, etc.  One of their customers for bicycle-frame castings was George Hendee.  In 1901, Hendee, having formed the Indian Motocycle Co with Oscar Hedstrom, approached Aurora to build the first of their 'production' engines, as Indian had yet no forge or casting capability.  Hendee had already built 3 prototype motorcycles (cycle-pacers) with engines very similar to the ubiquitous DeDion design.  Aurora agreed to build the motors and supply component parts to Indian, with a 'non-compete' clause, stating they would not build their own motorcycles.
The first Thor v-twin from their 1908 catalog
The first Indian 'Moto-cycles' of 1902 used Aurora-built engines, 137 to be exact, and their archives note an 'unreliable and sporadic' supply of engines.  It is speculated that Indian themselves built the rest of their machine, although it is likely Aurora still provided chassis lug castings.  In a 'letter of the law' move, in 1903 Aurora formed the 'Thor Moto Cycle and Bicycle Co', which sold all of the parts necessary to build a motorcycle, in kit form.  While Thor per se did not sell assembled moto-cycles, a few other companies appeared in 1903 with Indian/Thor clones, although each was different, as Aurora sold no 'jigs' to build their frames, thus each was 'different enough' to avoid a lawsuit.
1911 Model 'O'
 The similarity between these different makes, all built with the same components, has resulted in much current-day confusion for restorers; is it a 1903 Indian, Thor, or something else?  The list of these early machines, built from Thor components, is long...according to Gregory Walter, they include "Thoro-bred, Reading Standard, Merkel, Apache, Racycle, Manson and in years later Sears and Torpedo."  Even Cyclone, Henderson, and Harley Davidson used Aurora parts.
From the 1913 catalog
 By 1908, the agreement with Indian having expired, Aurora began selling complete motorcycles at 'Thor', and established a dealer network.  That initial single-cylinder model, slightly updated, was joined by a v-twin with the engine distinctively canted forward, and atmospheric inlet valves, as with the single, and most other American machines at the time. Both models used Thor's own updraught carburetor.
1912 and later free-engine clutch with integral 2-speed gear cluster
1912 saw a redesigned range of singles and twins, with proper mechanically-operated valves, and the option of a two-speed bolt-on transmission  and clutch (above).  Schebler carburetors were now an option, as was a 1,200cc engine for the twin. By 1915, a new, cast-iron, bolt-on two-speed hub was available for Thor and other manufacturers (Henderson 4s used them), although this device was infernally heavy.
Ca.1912 Thor racer.
Regarding racing: from 1908-1912, Thor fielded a racing team, managed by William 'Bill' Ottaway, which had some notable successes after Ottaway - a gifted engineer - had tuned the engines, achieving results perhaps beyond any natural advantage of the Thor engine per se, as Thor seems not to have developed special racing engines as rivals Indian and Excelsior had done.  Ottaway's success was noted by the ambitious Harley Davidson management, who had never before supported racing, but saw the huge sales impact of race victories.  H-D lured Ottaway from Thor in 1913, and the incredible success of his racing team could be credited with raising H-D's profile from 'solid/dependable' to 'world beater' in just two years, with sales, as predicted, rapidly rising.  Thor, after losing the ace up their sleeve, offered in their 1915 catalog a 'Short Coupled' (shortened frame) racing machine to the public, and according to Gregory Walter, these were 1914 models 'tarted up' as racers, and not especially competitive.
Restored 1914 Thor twin
By 1916, more changes were afoot, and the last 'new' design meant a proper clutch and 3-speed gearbox, and a new single-cylinder design appeared in 1918.  Production must have been very slow during WW1, and the Aurora board of directors, finding profit in other manufacturing areas, agreed to cease motorcycle production in 1920.

Below are detail shots of our Board Track Single:

Original paint, original grease, original decal
Note the 'breathing' holes cut into the cylinder barrel; typical racing practice, albeit very messy!
The headstock showing the Aurora transfer; last patent listed is 1912 - from this we infer our machine is ca.1913, or slightly later.  Note original friction tape wrapping the controls.
Messinger 'Motorcycle Racer' saddle
The fine art of Edwardian pinstriping...
Schebler racing carburetor, with no throttle!  This Thor is ridden wide open, or stopped by the magneto cutout on the handlebar.

Many thanks to Gregory Walter's Thor Motorcycles website  and Dan Statnekov's amazing Pioneers of American Motorcycle Racing website for this information!


Bozi said...

This was an excellent lesson, thank you for posting it. Yes the confusion of whats what from those few years make this article that much better.

What a find that bike is for people doing other restoration to have a valid reference point.

Thank you, Jeff
Saint Motorbikes
Saint Motor Company

Anonymous said...

A complicated history well explained. Thanks. Detail shots much appreciated. Incredible to see.

Paul E.

OcchioLungo said...

Bonjour mon ami.

yea, more pre16 stuff!

Thor's were interesting bikes, that's for sure. When they added pushrods and rockers for the 1912 season, the rockers were made from bent sheetmetal, with the pivot bolt just running on a hole drilled through the sheetmetal thickness. These didn't last long (as you can imagine!) But by 13 they had beefed up the rockers a bit with thicker material, still using sheetmetal though.

Another neat feature was the gearing in the crankcase. You can see a bit of the layout in your photo of the clutch, but inside the case there are gears to reduce the speed from the main shaft to the output shaft. Then a VERY long chain went to the rear wheel and 2 speed hub.

Wes A. and Mike T. have been touring on their Thor twins for a while here in Alta California, it is great to see them going down the road. That clutch lever is neat too, it twists as well as moving forward and back along the side of the tank. Twist changes gear, sliding engages clutch. Thor pics:

Au revoir

mp said...

argh, that engine number area has been "over restored" ha ha.

I'm sure You know about the Wheels through time 1913 Thor twin racer, I like to view the video of that thing.

The Vintagent said...

@Pete; thanks for clarifying the gear case; I was a bit unclear whether All gearcases fitted on the rear axle, or just the late, cast-iron ones. This one seems pretty neat, although yes, that's got to be the longest chain run ever!

@MP; Yes Wheels Thru Time has a really nice unrestored twin racer, but this is the only Single cylinder racer I've ever seen. Thanks for the video link!

Buzz Kanter said...

Wonderful Thor info and photos. Thanks for sharing on a topic hard to find much on.

And is there any truth the name Thor came from the comfort level of the racing saddle?

JJ said...


A fascinating hoistory. The following links to a youtube video, shot at the 2009 Veteran m/c rally in Albany Western Australia. The subject is a 1916 V twin Thor.


The Vintagent said...

@Buzz; Thor must come from all those midwestern Scandinavians...but can you imagine 100mph and zero suspension, high-pressure tires, and that saddle?

@JJ; That Thor is a long way from home...I'm always amazed what turns up Down Under. Got any Cyclones?

occhiolungo said...

JJ has probably seen that loads of American bikes were sold new in Australia in the 19teens. It was a big export market for the American companies (and Brits too). But in later decades many of the bikes lost their motors during scrap aluminum drives (to support the war efforts, etc). So there was/is a surplus of bike chassis and sheetmetal needing motors. One or two Americans have exploited this in the last 15 years and bought containers full of bike chassis down under and shipped them to the US for re-sale.

Kai said...

Could you please clarify or elaborate on the 'breathing' holes in the cylinder? I've never heard of that and it seems quite interesting.

occhiolungo said...

hello Kai. in the 19teens and 20's, cylinders were ported by drilling holes in the bottom of the barrels. these holes opened the combustion chamber to the atmosphere at bottom dead center, give or take a few deg. They let the exhaust blow out, and let in a bit of fresh air. They also blew oil out of the motor (constant loss oil systems have oil above the piston) which made the bike messy and the track slippery.

The flames coming out of the motor are a great sight! Combine those with the noise and speed and it is a great thing to watch.

motoroz said...

Great info. I just visited the Wheels Through Time museum in Maggie Valley, NC. They started up a 1913 Thor racing bike for us. Way cool! Will have video posted on my blog soon. (if you are interested - Love your blog.

Chopper Dave said...

Absolutely Fantastic... Thanks for sharing

Anonymous said...

The term "MCHY CO" might mean McHenry County, the rural (at that time) county north of Aurora which is in Kane Country

Anonymous said...

This is a fascinating find.
RE June 17 anon:
Prevalent practice at that time means that MCHY. CO. abbreviates Machinery Company. As does AUT. abbreviate Automatic. The location does show on the tank as Chicago, ILI.

Anonymous said...

I absolutely love this blog. I first got into really old bikes when i was working as a canadian tax lawyer and i've been hooked ever since. Thanks for the post

Anonymous said...

I am really keen on finding the detail of the decal on the headstock. I am restoring a 1914 twi wich has the deacals outline but no detail on the patent information. I have e-mailes the Solvang museum but no reply. Can someone help?
Also pinline detail would be good?

Mike W said...

I never could figure out why the lettering on the tanks on some of the earlier models indicated it was a Chicago company, as does the
2nd paragraph of the above article. The factory was actually in Aurora, Illinois, hence the name of the company, Aurora Machine and Tool Company. As far as I am aware, the offices and manufacturing facilities were always in Aurora and never in Chicago. I actually worked at Thor Power Tool Company, it's last incarnation, until I was drafted into the Army in 1972.

The Vintagent said...

It is indeed curious the name of the Aurora factory is the name of the town it was situated in, but the transfer still says 'Chicago'. But, every web entry mentions Aurora as a suburb of Chicago, which it must have been even in the 'Noughts. Perhaps not wholly subsumed into the conurbation though...