FMF exaust adjust

I got me a brand new FMF powercore IV exaust for my wr426f and i installed it on the bike about 3 weeks, but now i wonder if i need to adjust something in the bike like jetting or throttle, the bike seems to run fine!

Can i damage the bike if i let it stock in the adjustments? :applause:


You should not be able to damage your bike. The FMF Powercore 4 should require rejetting. But if it runs fine you are good to go! :applause:

How can i see if the bike needs to be rejetted?




I believe that the big signs are if you gets pops or backfires on deceleration, hesitations, bogs, etc.

i installed a factory 4 to my wr450 05 and needed to jet and lift the needle to the top clip. it runs like a dream now! i recently installed a FMF quiet insert and it is great- More power and sounds great too :applause:

Thank u for the inputs!

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