Stock YZ pipe with discs works well

Hey lads,

I have a 1999 WR400 with a stock 1999 YZ400 pipe installed. I have YZ timing and jetting.

The pipe has been freshly repacked and I am running a "disc cap kit" from Bill's Motorcycles Plus in Salem, Oregon ($149) (888) 806-1153.

There are currently 12 discs in place and the performance and sound level are pretty good. Sorry, I don't have a meter handy as of this posting for specific db's.

Most MX racers will part with their stock pipe for $100 or less, in search of big power from the aftermarket units. I previously had an FMF Powercore IV installed. It made tons of power but at ear-splitting levels. Although I lost money on the deal, I gladly traded the FMF bomb straight up for a stock YZ unit.

I'm not saying that a stock YZ pipe with discs is the cure-all for everyone, but it works for me.

I am also the vice president of the Arizona Trail Riders, and our group is constantly reminded of the excessive noise issue. Overall, that's the biggest gripe from the anti-OHV opponents.

Protect wildlife and habitat - stay on roads and trails.


Just ordered one for my 99YZ. I was wondering did you notice much power change or a need to jet different? Also any lessons learned during the install?

Thanks Shawn


99YZ400F (him)

00TTR125 (her)

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