I have modified my pipe in stages, just so I would not get to a point of regretting it too quickly.
Initially, I just (carefully) drilled holes through the end cap and baffle immediately inside. Looks kinda neat, like a gatlin gun. This did virtually nothing as far as sound, and I could not feel any improvement.
Next, I pulled the end cap off (once again, carefully grind the spot welds on the allen head bolts) and drilled many holes in the baffles. Sorta like swiss-cheesed it. Make sure you get equal number of holes on each side.
Still not much "growl". Actually, pretty disapointing.
Up to the next step, everything is very easy and quick.
Now I got serious and decided to "gut" the cans. Besides, if I don't like the sound or it runs crappy, stock cans are a dime a dozen.
This takes a little bit of work, a little more time, and a LOT of patience. Basically, just remove all the black steel you see inside the cans. Alternate drilling and chiseling (yes, chiseling) from each end. Took me about 2-3 hours on the first can, and about 1-1/2 hrs on the second.
I did not have any special tools, though I'm not even sure what type of tools might have made it easier.
Wonderful, fantastic, a sympony to my hears. Suprisingly, not loud at all at idle/low RPM's. Just a "watch out, I bite!" growl. If you are old enough to remember the CBX, and ever had the opportunity (privilege) to hear one with a header, the Hayabusa reminds me of that.
Only been done about 1 week, so I will be checking the plugs this W/E. It does not appear to be running any warmer, and absoulutely no flat spots (at least up to 7500 RPM).
On a scale of 1-10, I would give the results a solid 7-8 (single can looks better).
