Very interesting when you get into the art of 2 stroke expansion chamber's it essentially is kind of supercharger the sound waves come racing back into the cylinder just as it closes and boosts compression. And changing the shape of the pipe changes when that point happens so those old scarey 2 bangers could of had a change in pipe n bring it on easyer and softer but then give away top end. All a big compromise but dam there fun when there late. A YZ 250 is allways more fun than a yzf450. 4 strokes are boring in mx and way too expensive also any more than 2 strokes is a **** haha
