Sunbeam Model 6 Longstroke pistons now in stock

Sunbeam Model 6 piston

Following on from the successful production of pistons for OHV 500cc Sunbeam models Chris Odling and I thought it would be useful to produce some high-quality forged pistons suitable for the Model 6 side valve long-stroke. The Model 6 was produced from 1922 until 1939 becoming known as the Lion after takeover by ICI. With its 77mm x 105.5mm bore and stroke this was the last side valve powered motorcycle to win a Senior TT.

There were of course changes along the way and the piston produced is nominally compatible with models produced from 1925 until 1929. Before 1925 a 5/8″ gudgeon pin was used rather than the later 7/8″ type and the change to a scavenge pump from total loss oiling in 1930 means a different piston ring configuration is required. It is possible that these pistons could be adapted to suit.

I have limited availability of pistons in 77.0mm +0.000″ and +0.040″ sizes. An all-up  weight of 434g has been achieved for the 77.0mm which is within 2g of the target weight that we set out to achieve.

Once we have given the new items a good look-over I’ll be contacting those who have reserved pistons already and adding them to the Sunbeamland shop.

 

1933 Model 90 for sale

Steve Griffith over at Racing & Investment Motorcycles has turned up yet another interesting Sunbeam Model 90. This time it is a later saddle tank that he has for sale that reportedly has come from the Joe Potts collection. Some interesting features on the bike include the very nice twin-float Amal 29/001 carburettor that also looks to be stamped M90. I would love one of those for my own ’30 saddle tank if any one has one? The single port head is fitted with coil valve springs and appears to be of an earlier vintage due to the design of the rocker box side plates. Open primary drive, rear set-foot rests and the rare left hand filler oil tank complete the sporting look perfectly.

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