topolino

I have had this engine in my shop for years and thought it was a YDS3 until this morning. It has bore of 50.46 mm, obviously an overbore. The intake manifold is 18mm. It must be a 180 but the YCS1 motor number does not come close to the D100 prefix. It is a 3 port engine and in good shape, no pistons in the engine, turns free. Wot the hell is it. I have raced TD1C, YM1,YR2, RD350 ETC. My regular ride is an OSSA 250, turns 12400 and 46 hp at that rpm, I was timed at Mid Ohio backstretch at 137, but at 230 pounds and 74 years old at the time it was pretty good. My young rider should break 140 this year at Daytona. I have since retired but am building a YDS3 to TD1B specs : stared racing in 1948 on war surplus Indian. When I worked in London I spent my weekends at Brands Hatch. Loved it. Oh yes, am building a Harley Hummer for dirt track racing. I hope I can match some of the great Bantams I saw at Brands. Enough of that, hope someone can help me with the motor number, Google cant.