Another exhaust question . . .

3 replies to this topic
  • rdefonce

Posted July 16, 2009 - 10:35 AM


My bike: '08 YZ450F with FMF Megabomb 4.1 complete system.

I am changing my straight-thru FMF MX 4.1 muffler with an FMF Q4 muffler/spark arrestor, but keeping the same Megabomb header. (temporary change to do some off-roading, I will change back to MX muffler soon though)

Question: What, if any, jetting changes would this require?


  • rdefonce

Posted July 16, 2009 - 05:27 PM


OK, I'll make it a very simple YES or NO question:

Do you think it will need ANY jetting change at all, yes or no?

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  • MATTH530

Posted July 16, 2009 - 06:27 PM


Maybe On The Main "stock"

  • rdefonce

Posted July 17, 2009 - 05:12 AM


Maybe On The Main "stock"

Ah, OK. That's what I was figuring; if anything it would need slightly leaner jetting with more restrictive pipe. Just wanted to bounce that off the experienced guys.

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