Just an update. As Short Stroke engines start off 1/16″ bigger than long stroke engines, then I have decided to get two sets of core tooling made so as to keep the skirt thickness and thus weight within reason for both types / size ranges. I have had initial samples but my guess is that it will be 2013 before a batch of heat treated castings are available. Unfortunately it is totally uneconomic for me to machine up all variants of Long and Short stroke in standard oversizes and put them in stock. It will therefore be a case of machining up each pair once the size and type is known.
Richard Blackburn has said that he will produce 500cc pistons and stock them in LS and SS versions as finished pistons in regular oversizes. I am machining a small batch of 600 DPY barrels mainly because I need some for customers. The cost of the castings was over budget and with such small numbers, it will not be possible to produce them at a price that would be acceptable to most owners. Where an owner wants an engine with a bit of extra GO, then I can machine these up with the inlet system similar to my more expensive Aluminium barrels with chromed and ground bores as used on Yamaha TZ engines. With the saving over a full new sports motor, then one customer is having a replica of my front race brake. Once you allow a Scott motor to breathe more easily, the next problem is usually getting it to stop! I have nice new crankcase cups to fit where the bores in the original cases has become stretched and nowadays I do not build with original glands but use bronze thrust pads to control end float and synthetic seals and non return valves. The next object of interest is to investigate if a nice lightweight clutch can be hidden away as the original does cause some vibration. If you are interested, take off the primary chain and kick starter, then drive the 1/2″ square with your electric drill and see how much shake you get. If you see cases regularly, look at the inside face of the LH bottom crankcase lug. Very often you will see evidence of wear due to the out of balance of the clutch rattling the undertray on that side. Once it wears and the fit of the undertray is slack, then if you try and tighten the bottom bolt, you are in danger of breaking the lugs. And on it goes
. But then, following the trail of logic and trying to eliminate observed shortcomings is a fascinating exercise.. Roger