Thor 1912 Model CT IV HP ca. 488 cc aiv 3509

Thor 1912 Model “CT IV HP” ca. 488 cc aiv single engine # TL416

Thor motorcycles were made by The Aurora Machine and Tool Company, which began as a machine shop in 1886, providing forging, castings and parts for many bike manufacturers. The history of Thor is closely tied to the history of Indian motorcycles, as somewhere around 1901, Oscar Hedstrom of the Indian Motocycle Company accompanied an Indian prototype to the Aurora factory – Aurora had been supplying the Hendee company with castings for their bicycles.
After several months of collaboration, the Aurora company produced a new motor design of Hendee. The two companies struck an agreement that entitled the Aurora Company to supply engines for Indian as well as have the freedom to sell additional motors to other companies, paying royalties to the Indian company, so long as Aurora did not enter into direct competition with Indian. By 1902, Aurora had produced almost 150 engines for Indian.
In 1903, the Aurora Company produced a catalogue of parts from which a motorcycle could be built, with the exception of a frame. Thus began the Thor Motorcycle and Bicycle Company.
From 1903-1905, Thor components remained largely unchanged, and many manufacturer’s designs, including Indian, are very similar. When the Indian Motocycle Company gained their own in-house foundry to produce parts, Thor started offering complete machines, ending the prior agreement with Indian.
By 1908, Thor offered both battery and magneto ignition, as well as either chain or belt drive. They developed a design featuring a twin with automatic intake valves, which had been problematic for both Indian and Harley. Thor continued to make advancements, changing with the needs of an ever-growing popularity of motorcycling, and the racing culture.
In 1916, Thor offered a three-speed transmission, which was one of the last design changes initiated by the company. While the Aurora Company continued to manufacture forgings and components to other motorcycle makers such as Reading Standard, Indian, Merkel, Henderson and Harley, by 1918 the Thor motorcycle production was diminishing. By 1920, the board of directors announced a cease of production of Thor motorcycles, however Thor continued to produce power tools and home appliances such as washing machines, irons, and dishwashers. (source: http://www.motorcyclepediamuseum.org)

The 1912 Thor range consisted of no less than six models, four of 4 HP with choice of battery/coil or magneto ignition and chain or flat belt drive, one 5 HP machine and a 7HP twin; the latter two models were fitted with Thor patented two speed gear. The CT model was essentially the same as the 1911 machine, with the exception of the front forks, that had got a stronger construction. The CT is fitted with a remarkable system: a free engine and belt tightener, operated by a single lever. By means of the lever the rear frame can be moved and thus its geometry can be changed. In this way the flat drive belt can be slackened or tightened and a “free engine” is effected.
The rare 1912 Thor we present here has had her engine reconditioned with new big end, main bearings, piston and inlet valve. She has been used as a display item and will need to be recommissioned. She comes with Steward speedo head, Solar acetylene lamp and handlebar-mounted push horn. Tyre size is 28 x 2 ½ x 2 and stopping power is provided by a back-pedalling brake.