XR650R FMF PowerCore 4 Squared

I have a 2002 XR650R with the B53E needle in position #3, 175 main and stock 65S pilot with an FMF Power Core 4 Squared pipe. It does not seem to have the same bottom end power that my buddie's 2000 has. He is running the 65S pilot, 175 main, the stock needle in position #4 with an R4 White Bros pipe. Could it be the pipe? Anyone have any experience with these pipes? Any suggestions?

I would up your pilot to the 68s. I bet it's that your throttle response is off due to being choked by the 65s.

That's what I was thinking of trying. The only thing that is throwing me, is that my buddy is running the 65s. My 2001 had the same exact setup as well, except for a Powerbomb header and a power core IV. I was thinking about swapping exhausts with my buddy and seeingig tha makes a difference as well.

Rode my bike today and installed the 68s. What a difference. Now it pulls off the bottom like it should. I have the new style UNI filter installed and I think that's why the 65s did not work well for me. My buddy is running the stock filter and backfire screen, so maybe that's why his works fine with the 65s. Thanks.

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