FMF Powercore 4 Slip on

I know I want this slip, but I'm wondering if I'm going to have to Rejet. I'm buying just the slip on, and my bike is a 2001 DRZ 400 E model! 


I also have a R&D racing Flex jet fuel screw, Don't know if that helps.


Do any of you have the Powercore 4?  did you rejet? if you didn't how does the bike perform?

The elevation where I'm at is low, Phoenix Arizona

Thx for any help :ride:

The only gains you're going to get is noise. No need to rejet.

I had a ProCircuit T4 slip on which is similar to the FMF and felt no different to the stock pipe at all.

A largely noticeable difference was when I did the 3x3 rejet and a new header which was the same size as an E header. You may feel some difference with the slip on as the header is already bigger then a stock SM.

The stock header for me was a big restriction to the bikes performance.

Edited by harry9395

Thanks I'm not really looking for a power gain! hahaha Loud pipes are easier to follow here in the Arizona desert Hare Scrambles!

Waste of money IMO...get the MRD/SSW you won't be disappointed... I love mine and the gain was well worth the wait and the price!

Mrd is loud is hell. +1 on Mrd.

Get the FMF PowerCore 4 with the quiet insert!

My DRZ has a full yoshimura not sure if RS1 or RS3, they look the same to me, it has no silencer, you can hear my bike from miles.


Since its the DRZ-E we're talking about I'm guessing you wont be road riding, or atleast highways, because that exhaust make you lose your mind after a while on the highway, the sound is way too loud any annoying on the highway.

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