When the piston is on its downstroke there is some of the charge from the crankcase gets pushed back up into the carb before the reeds have time to close.

When the engine is off the pipe this effect is even worse because of bad reflections. This blowback ends up in the airbox and pollutes the next charge in older 2 strokes. The boost bottle gives this somewhere to go as during the cycle when the piston is on the upstroke the pressure in the bottle is low. When the piston is on its way back down the very second the reeds can pass charge its on its way. Without the time it takes for more fuel to travel from the carb.

Sounds good but it doesn't make a huge difference, maybe a bit of bottom end torque. It was called Torque Induction on the RXS 100. Ironically a lot of the lads I knew who had them took the bottles off and blanked the manifold.

Works much better on twins as each cyl can scavenge the other, 350's have a pipe linking the manifolds together. Take that out and you DO notice.

Ah I get yeh , that pipe on 350"s , was this labelled "balancer pipe " ?

That's the one, lets the cylinders leach off each other better top end and better torque, (for a 2 stroke).

The exhaust/ mixture gasses travel a surprising distance in the engine. Next time you pull one down with decent mileage check out the transfers, they will have carbon build up from the exhaust gasses. Same in the reed block if its mounted on the barrel.

Well just fitted the rt180 boost bottle with reed block (std reeds) and been out for a spin. Kin ell loads of low end grunt and wheel lifting before the powerband. Smoother as well. No difference with higher rpm but he is still tight.

http://i235.photobucket.com/albums/ee14/Simon46/Mobile Uploads/DSC_0331.jpg