Originally Posted by ER70S-2
Stock exhaust dimensions:
Inlet: ID = 1.4"; OD = 1.51"
Outlet: ID = 1.135"; OD = 1.265"
If they removed the stock inner tube (the one that sticks out about 1/4"), when gutted, that will leave a hole; ID about 1.386"
FMF Model #S9000 Approved Spark Arrestor (thanks to mx_rob)(also available at Dennis Kirk, I think), is 1.650" OD and 3.38" long
For reference the GSXR muffler x40F0x outlet; ID is 1.680"
GSXR install (again thanks to mx-rob):
I'm a little confused with the exhaust dimensions. The end of the header where the stock muffler attaches is 1.135 ID and 1.265 OD? Im looking to build my own cheapo midpipe, and the pipe coming off the Hayabusa muffler is huge, i think over 2".