2 stroke

I have used 2 stroke engines for years (dirt bikes)

You can't go wrong with 150ml of best quality 2 stroke oil to 5 x litres of petrol.

I cannot stress the importance enough of good quality oil, cheap oil is the most expensive in the long run.

I allways use Castrol super TT it may be pricey but you only use 150 ml to every 5 litres so it aint that bad

Regards Slim

thank you and i must think a bit like yourself as thats what i have bought. its only a 43/49cc will that mix still be ok

( snipped-for-privacy@hotmail.com) gurgled happily, sounding much like they were saying :

At a wild guess, and based solely on the information you give, I'd suggest that about 25:1 would be the right mix...

The 150ml to 5 litre is a mix I put in cans and use it for,

Dirt Bikes 125cc and 250cc Mopeds 50cc Mini Moto 47cc Garden Strimmer 25cc Chain Saw ??cc Boat Outboard 65 hp Boat outboard 25 hp

I have never had a piston blow yet, also the dirt bikes get thrashed!!

Regards, Slim

And whilst I can't really imagine anyone thrashing a chainsaw, my outboard runs on a 10:1 mix.....

Smoky? Maybe! (Possibly a bit worse than my old DT175 in which I used Castrol R - smelt great!)

Artie

What kind of scooter is this? Is it an old one? 25:1 seems awfully high for a modern engine. Most modern engines from Japan in particular run a

Even if it's an old scooter, using modern 2 stroke oils it would probably be fine on 50:1.

Some modern 2 strokes can use a 100:1 ratio!

Chris

Sadly the two stroke is a dying beast. The engineering is there to have it as one of the cleanest burning engines around but no one wants to put in the investment, particularly one of the worlds biggest engine manufacturers.

I actually considered designing a 2-stroke development...

Seal the crankcase, so no transfer ports. Add a blower on the input port, and GDI fuel inject it. Use a power-valve on the exhaust port, a 3 stage catalyst, and a tuned pipe and EXUP valve before the cat.

Because there's no transfer port, and no need for oil in the fuel, the exhaust is much cleaner. There's also no total-loss oiling, so the crank and engine can be oiled in a conventional manner.

Finally, because it's a 2 stroke, there's twice as many power strokes per cycle, so you can get 2 litre turbo performance out of a c.1 litre engine. in the Bike world, a 250 two stroke twin is equivalent to a 400 four stroke engine.

All the advantages of a Rotary, none of the disadvantages.

Anyone fancy fabbing one up with me?

How about the 2 stroke cycle used in large ship diesels? Looks pretty close to what you're proposing. Ie they already exist, and are the most efficient internal combustion engines around. Could it be made to work in a high speed engine? (I suspect the answer is no due to the requirement to shift the entire cylinder volume very quickly at the bottom of the stroke).

cheers, clive

I wonder.

Power valve, and GDI fuel injection, as mentioned earlier. Supercharger.

Now for the silly bit. The intake valves are in the piston.

This has obvious benefits, as it dramatically improves scavenging.

Oval piston. Conrod, and crankshaft slightly altered so that half the crankshaft is deleted, and it's supported only from one end. This only works simply for 2 cylinders.

On either side of the middle of the piston is an intake valve, which is connected to a manifold inside the piston, connected to a tube going down, outside the crankcase, through piston-ring like seals, to take input from the supercharger.