Which Headpipe is best? Prove It?

I have the stock WR headpipe with a YZ muffler on my WR, many of you have said the YZ muffler makes as much or more power compared to the after market ones available from WB or FMF etc. which is what prompted me to buy it. my question is does the stock WR header outperform the options as well or would a tapered header with a YZ muffler provide better all around performance?

Anyone have any dyno proof to back up claims?


stock yz silencer will give more HP than stock Wr silencer,but wb,dr.d and fmf silencers will all add 2hp to 4hp more than yz silencer.wr and yz headpipes are exactly the same.

My bike has the complete DSP exhaust system. On Monday it will be on the dyno. After a few runs they will remove the DSP system and install a FMF pipe with the power bomb header and measure the difference.


Why don't you wait until after the June ride. I'll give you a stock YZ pipe to try also.

Team S,

The tapered header is supposed to help make bottom end power. Now whether that's at the sacrafice of the entire powerband moving down or additional HP at lower RPM's. I don't know.

Bill :)

Bill, are you telling me a stock YZ exhaust on a WR 400 might compete with a DSP or a FMF Power bomb system? Fred

No, I'm saying it would be nice to have some data on the YZ pipe (lesser cost alternative) and after market header vs. after market pipe and header.

I have an extra YZ pipe I've been meaning to mess with but, I'm still fine tuning my "taffy" jetting and don't want to throw another variable into the equation. Plus, I have such little time to ride, I just wanna ride :)


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