Sunbeam. Cdm: S8. 1956. 500cc.

APPRECIATIONS: The paint is in good condition in general. Seat upholstery new. Chrome in good condition lack of Polish. Trims in good condition and original. Shifters original. Tires somewhat worn. Change and piers with oxides visible. A hydraulic suspension. Needle oil level drop.

You do not have documentation, we would have to make a historical. (Custom quote with our manager).

EXAMINATION OF RESTORATION OR DAMAGE: Significant. Good general condition deteriorated due to disuse, nothing serious. Old restoration. Chassis with desconches in the paint. The exhaust pipe is not in the model, plays with kickstarter. There is that change electrical wiring. Worn-out tires. (Custom quote with our restorer in our workshops).

Motorcycle Sunbeam. Model: S8 Year: 1954. 500cc.

Models

There were three models, the S7, S7 "de luxe" and the S8. The three were very expensive with only a yield modest that resulted in lower sales. The original model was the S7 (the "Tourer") (2.104 produced from 1946 to 1948), in 1949 the S7 was updated to become the S7 deluxe (5.554 produced) and the S8 (8.530 produced). Both had new coatings for cylinders, frames, redesigned and increased oil capacity.

The lighter S8 was sold as a model "sport" with a maximum speed of 85 mph (137 km / h). It also had new forks (BSA), a silencer cast-aluminum wheels and chromed (with tires more narrow to replace the tires "balloon" that had given rise to a handling uncertain speed).

Models S9 and S10 were planned but never made as BSA decided to concentrate on the twins more traditional.Another model, "sports" was also tested but never put into production. This had a compression ratio much higher with a design of OHC different, but never sold, supposedly due to the system of front fork is not damped that it affected the handling. There was also evidence with a strict version for a cheaper model but this design was also abandoned.

The S7 original was produced in black. The S7 deluxe came in "Mist Green" or black and the S8 in "Silver Grey" or black. For export to the outside, the BSA supplied sunbeams in any colour BSA.

Design problems

The design of Erling Poppe was originally based on a BMW R75 captured, but as soon after the end of the war, the BSA did not want the S-series look too "German", so a OHC in-line, a twin parallel was designed in place of a twin plane "through the frame". The serious problems with vibration made the new bikes Sunbeam were inconvenient to handle and we are reminded of the initial production originally sent to south Africa. The excessive vibration was cured by mounting the engine on two mounts of the engine of rubber attached.

The in line engine was inherently suitable for the transmission shaft , and bevel gears-style BMW would have been ideal. However, having inherited some machines helical gears of Lanchester Motors and BSA chose to specify the drive screw in place of bevel gears. The helical gears were totally inadequate , as the direction of transmission (input shaft vs output shaft) is not reversible when using reduction ratios large. As he says, this created problems with the transmission shaft, because the gear tended to break off under tension. It is said that the "solution" of Sunbeam to this was to reduce the power to 24 bhp (18 kW), which did not contribute to the sales of the post-war period.