ADD.

 I think I may have ADD I prefer to think I'm easily bored and have far ranging interests. In any case it can't affect me as I'm nearly seventy one, it's kids letters and a teachers excuse for being tedious.

I was discussing small racing bikes with the haircutter a month back, don't panic, we've formed a bubble. We chat when we want. I said I've been looking at 125cc two strokes and when the boys get older, they are doing kiddy motocross at the moment*, it may be worth building a nice engine for them. Two stroke technology has come on a long way from the Villiers and Lambretta stuff of my youth. The latter engines were for vegans, always popped in scooters that kept the engine behind one so you didn't get dirty or smell. Now Yamaha and Honda were making wonderful reed valve engines a few years later. I thought to pick one up for fifty quid, use the bottom end, clutch basket, gearbox etc. Design or steal the design for an electronic fuel injection system, with a slide throttle to pop on a new cylinder barrel with really posh porting. I'll not bore you here but sealing the piston to the bore is a massive problem. Too large ports and the piston rings disintegrate. The answer could be one silicon ring and a two part piston. The gudgeon pin in the piston and then screw it into an outer smooth slave sleeve with one ring. 

Now the downside, I couldn't believe it, Victor Meldrew eat your heart out. The cheapest Yamaha engine was donkeys years old, well worn and advertised at over a thousand pounds. I surfed t'internet and found some more at silly money. Some of these are almost half a century old.

This looked the best. £1200.00p. I'll get on the bike forums for one that has seized up.

* They did do Kiddy motorcross till the bastard MSM and politicians took a year of their lives away. What for? To save selfish hypochondriacs and the NHS, that's what for. I hope it is, be funny if the WEF had an alternative agenda for the gullible.