MX Bonz airbox fix

Nov 7, 2001
I'm currently installing the MX bonz airbox fix on my 02 cr250 and
have a question for those of you that have already done this.
I trimmed the locating nubs on the airboot side & completely
removed the nubs on the air filter side as the instruction state.

My question is regarding the very thin raised lip that goes all the
way around the airbox where the new intake flange will seat. I'm
thinking of removing this lip so the intake flange will make contact
with the entire surface and not just on this very thin lip. It seems
to me this would be a much better fit. Has anyone else done this
or see a reason not to??


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Dec 26, 2001
I removed the thin inner lip to get better contact like you talk about. I also felt like the flange was less likely to distort by seating it flatter.

Frank, the maker of the MX Bonz kit, says to leave it as it makes a dam of sorts for the sealer. I think his method would require you to use far more sealant to fill that big gap....but I don't see why one would be much better or worse than the other.