YZ426 FMF Q4 Exhaust Diameter!

Hi, I need to get a Q4 exhaust but I need to know the diameter of the exhaust at the spot where it slips on to the header. My header is 1-7/8" of an inch and I need to know if it is the right size. I don't want to spend 300+ and have my header be to large or to small. If you know it will fit or you have the diameter please tell me! Thanks

I can measure mine if you want, but my Q4 came with 2-3 sleeves that I didn't need for the stock 09 header. I was a little concerned at first as the place where the pipes join doesn't use a clamp, but I slobbed it up with copper stuff (as the directions recommend) squeezed it together and waited till the next day to run it and it has been fine. It was a very tight fit over the stock header and the copper gasket stuff sealed it well, I have no backfiring.

Hope this helps!

Ya thanks for the info. my exhaust header is not stock that is why i am concerned, if you measure it for me i would really appreciate it. When you mentioned "sleeves", you mean like different types of fittings depending on your header size, right?

1.782 inches. The sleeves reduce the diameter for smaller header pipes. Of course this is a Q4 for a 09 450, I just noticed you specified a 426, sorry!

do you think they are all pretty close to that size?

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