Power valve vs. no power valve?

[MXrider6969]

I'm getting the yz85 or a ktm85sx so is the power valve on the ktm going to be much more of a difference? Or is having no power valve more fun? Or having no (PV) a disadvantage?

I ride on both track and on logging roads. Thanks!?

[7thirtyseven]

The 2 stroke is dependent on the back pressure of the exhaust to run properly. The power valve is a means of adjusting the back pressure so that it can run better over a wider rpm range. It opens and closes with varying rpm adjusting the back pressure, or pressure waves. Other ways of adjusting are switching pipe designs etc.

All other things being equal the bike with the power valve should have a broader power band and be more rideable.

Can't tell you which will be more fun... some clowns think a massive hit is great, they can feel out of control in the gravel pit while dad drinks beer on the back of the quad. Others like Johnny Walker choose silencers etc that smooth the bike out a bit.

[Mike in Fresno]

PV will be more rideable on the trails

[MXrider6969]

Oh ok thanks for all the info. I guess I'll have to try both bikes out and see what I'd like. Thanks again

[MXrider6969]

Is the yz's power band really that much better for the track or is it worse? Or is the ktm's power band better for the track?

[7thirtyseven]

Is the yz's power band really that much better for the track or is it worse? Or is the ktm's power band better for the track?

These are personal preference questions. In the grand scheme of things the bike will be just a transition toy, get the one that will cost you the least to own for a couple of years. Performance wise unless your leading a provincial series, you won't notice much of a difference IMO

[rpt50]

Kx 100.

My son went through a bunch of mini MX bikes. The 100cc was the best all-around bike.

The ktm 105 is incrementally better yet, but the don't come cheap. You will likely get the most value from a kx.

Edited August 7, 2014 by rpt50