Well, I don't think I bent my frame or distorted my cylinders pulling on the pipes, but I did get my Busso No- Stamp 300 style exhausts installed without any cutting, drilling, or grinding. Bottom line is, I would not recommend the Busso 750 Pipes; and if I knew back then all that I know now, I would have passed on the Busso group buy and ponied up for a set of the Yamiya pipes if and when they became available.
For anyone still following and interested in how I dealt with the right side fitment issue at the brake pedal, you will recall that the less than adequate cutout in the #4 muffler did not provide sufficient clearance for the muffler's top weld seam to clear and tuck in under the bolt in the clamp of the brake pedal. See Rookster's pix of the Yamiya set above.
I never heard from anyone with a stock K1 to learn where the #4 muffler's weld seam lies in relation to the brake pedal bolt.
With or without wedges in place to bring the weld seam down to clear the pedal, when the rear bolt was tightened, as the #4 pipe moved inward, it would bind up and pivot about the brake pedal (or the wedges) pulling the front of the #4 pipe outward and the rear of the muffler inward which made it impossible to align the balance tubes.
The eventual solution, for me anyway, was to fabricate and insert a 1/4" spacer bushing between the two mounting sleeves of muffler 3 & 4. This solution results in the #4 muffler's weld seam to be outboard of the brake pedal bolt with the pedal's clamping section to rotate nicely in the dished out section inboard of the seam. The spacer allows the front of the #4 pipe to tuck in nicely and be parallel with the downward section of the #3 pipe which was wedged in two places to clear the frame and oil pan and at the back the balance tubes lining up very nicely. The solution required a slightly longer mounting bolt which for now is a 1/2" x 6" inch hex bolt until I get around to modifying a longer 14 mm bolt.
Another fabrication/quality control issue with the Busso pipes is the position/length of the muffler mounting sleeves. In the following pic, you can see the very small clearance between the peg bracket and the heat shield. I have NOT cut an indexing notch on the #1 muffler mounting sleeve as this would allow the bracket to contact the heat shield.
On the right side, still with no notch cut in the #4 mounting sleeve, you can see there is a lot more clearance at the heat shield.
I'm still pondering whether or not to cut any indexing notches at all and destroy the chrome surface???
ZT