exhaust pipe clearance

The exaust can be bent. take the pipe and secure it in spots with wood clamps or whatever and bend it a little at a time. Just do not get crazy with it and crimp the pipe.

I had the same problem with my last build. I loosened up exhaust bolts and retightened (after reapplying sealant) as far to center line and right as possible. When done I was less then a sixteenth short of crank not tapping the exhaust. Was a day of never ending near misses and bad investments and that light hollow tap sound sent me over the edge. I put one hand on the seat and one on the handle bars, put the bike straight up and off the kick stand, took careful aim and kicked the bottom of the muffler.
This is so, so wrong, but worked perfectly. I am in no way suggesting any one try this. (but cracked me up and I bought a bigger rubber mallet)

What I did was stick a 1/2 inch extension in the pipe. I put the other end of the 1/2 extension in a vise and pulled on the muffler side a little. I bent the pipe a little and that made the pipe clear the cranks.