FMF 4.1 vs Powercore

[CanadianWR450]

I got a 04 WR 450, (Free mods done, rest stock..)going to freshen it up over the winter...

Going to put a pipe (slip on) on while I;m at it, and have it pretty much narrowed down to the 4.1, or the powercore.

No EPA laws here, don't care about noise, don't need a spark arrestor, and I don't really care about weight, bike is a fun / trail beater...

I called FMF and they actually recommended the Powercore over the 4.1, based pretty much on the price difference alone. Price not really a issue as far as slip on's go....

Anyone have any real world comparisons for me?

I would be looking for more bottom end/mid range over top end.....

[KJ790]

If price isn't an issue, then the factory 4.1 is what you want. The powercore mimics the stock YZ exhaust, while the factory 4.1 actually gives power gains across the RPM range, but mainly a strong bottom and mid with a little extra on top.

[simica]

If you get the less expensive pipe, spend the extra money on a YZ exhaust cam. The combination of the new pipe and cam will wake up your bike beyond belief. I have done this with my '05 and I am a happy camper!

[DrzDasher]

look at yoshimura their trc comp full systems are 300 bucks, seems pretty cheap to me, i have the carbon slip on(came with the bike) nice sound

[CanadianWR450]

Cool, thanks for the info...I'll likely go with the 4.1, and the other threads saying after market/YZ intake cam, Hi comp piston, and stock ex cam got me interested as well...since I'm going to be in there.....

[tribalbc]

Cool, thanks for the info...I'll likely go with the 4.1, and the other threads saying after market/YZ intake cam, Hi comp piston, and stock ex cam got me interested as well...since I'm going to be in there.....

Let us know how it goes