A few years back I found this modified BSA B33 long stroke engine whilst helping the late Captain Maurice Seddon at his house. I was interested in the engine because all the cooling fins had been removed. the engine was empty, but in the cases there was a high compression piston and a valve. I wondered where the engine came from and who modified it, and what it's history was. I was quite pleased when I went to Kempton autojumble this weekend and saw this grasstrack bike there, sporting an engine that was modified in a very similar way. I know some of the older guys I have spoken to say this was a common modification "back in the days" (converting b33 engines and such to run on alchohol for competition) but being from a different generation I have not seen any of these.The owner of this grasstrack bike at Kempton said it was a "Coles" engine. Theis makes me wonder weather the engine in Seddons yard was also a "coles" engine. The pictures here are of the grasstrack bike, and the old engine I saw at Seddons.