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I would have like to see him wring the neck of the 90's YZ also.

The silencer is a comparatively minor part of the equation if you're talking about power characteristics. The 02 has different port timing and head dimensions to the new models. It was an impressive grunty engine which hits hard. If you don't want to modify engine components, go with a flywheel weight, a standard pipe and silencer and try adjusting the timing. After you try that and if you still want it more mellow, you can always put a slightly thicker base gasket on the cylinder.

I have a completely stock. '01 YZ250 that I run with a stock pipe and silencer. the low end is amazing and I think over the years Yamaha has added a little too much volume to the head which almost mellows it out too much. The YZ250x has considerably less compression (different head) than the YZ which lessens the snap off the bottom. I don't know why you think a flywheel weight won't help but the hot ticket was to run an 8oz flywheel weight even in moto. For woods/playriding people would even go heavier. The YZ-x probably felt pretty...

This is very solid advice right here. You don't get much from changing the silencer, but you can really change the power spread with a small change to the timing. The FMF fatty pipe is pretty good for drawing out the power and being super smooth on the YZ. I run a Factory Fatty at at some of our local tracks where the corners are flat or off-camber and the soil is slick. The PC pipe has a harder hit and pulls mid/top (probably not your flavor with the hit) The Bills pipe is more low/mid oriented. (if you can...

The X has a different head, CDI, and powervalve setup. You don't need to spend a bunch of money and copy these things though. I would start with retarding the ignition timing 1-2 degrees. The whole short silencer = more bottom end is not entirely accurate. Outlet size matters more. What exhaust setup you running now? I would just stick with stock if you're looking for smooth delivery. After, that FMF Fatty is known as being very well rounded. Pick any silencer.

Longer will smooth it out. Stock aint bad on a yz 250 i usually run stock ones these days

He put straight gas in it.

Look at the knobbies on back tire,,,, middle knobs are going backwards.