Kevin Williams' Bandit Header

My brother Kevin's main toy right now is his Suzuki Bandit. He was talking about buying a header for it. The word from the Bandit list was that the stock header was really a giant muffler; tiny inside, with fiberglass packing. Even with the straight-through muffler Kevin's is very quiet.

In the spirit of "fools rush in..." I volunteered to cut a spare header he borrowed from another Bandit owner up and remove all the muffler guts. Then he could do some back-to-back runs at the drag strip.

This hasn't quite turned into one of those projects from hell, but it's definitely on the "why quit when you're losing?" list.

If I ever have to do it again, I'll just use my fancy alignment fixture and bend a new header up from scratch.

update 01/2004: Kevin went ahead and bought a sidemount drag pipe, so I dumped the header project and salvaged some of the metal for other things.

I knew it would take a lot of cutting and welding to get the double wall tubes out of the header, so I built a rigid fixture to hold everything in alignment. The cylinder head is from a GSZR-750 (thanks Mike!) with the same port spacing as the big Bandit.

I made a pair doweled plates to go on the collector end. One plate is welded to the 5/8" steel rods bolted to the head, the other is welded to a piece of muffler pipe that is clamped inside the collector flange.

Remove the two 9/16" bolts and the plates separate. You can see the angle iron brackets bolted to the head in this shot; I had to have something to weld the bracing rods to.

Another view, just for completeness. I was sort of proud of the fixture...

A-sawing we will go, a-sawing we will go-o-o-o... The Bandit header is stainless steel and very hard. I flat wore out two bandsaw blades slicing it up. The tubes had to be cut off the collector first, then they could be sliced further as needed.

One trick I learned was to saw almost through the outer tube, but completely through the inner tube. Then I could slide the cut-off piece out and the outer tubes were still in alignment to make it easier to weld back up later.

For long curves, I just bent the sliced outer tube out of the way, pulled the curved sections of inner tube out, and bent the outer tube back.


I spent a lot of time trying to figure out what Suzuki was doing by bridging 1-4 and 2-3 cylinders. It turned out the big connecting tube you see there is just a shell; inside is a much smaller tube, maybe 5/8". The inner header tubes have matching holes, but they're not welded or sealed to that connecting tube.

Damfino what's going on here. I will probably grind all the stuff off and weld up the holes in the outer tubes.


The guts! "Lots of tubing in that-there header..." If nothing else, it'll be a lot lighter than it was before! The inner tubes were stainless, too.

The welds on the collector were even harder than the stainless housing, so it took a while to saw the collector up.

Yep, that's the same old Harbor Freight band saw kit chewing on the crossover. Probably the best $179 I ever spent!


Here's what was in the collector - a perforated baffle and a bit of fiberglass packing. There was probably more packing in there to begin with, but that's all that was left when I opened it up. Yes, the whole header really is a muffler!
The inner and outer tubes were welded together at the head flanges and the collector. I mailed them to Kevin so he can grind them apart in his spare time. When he's done he'll mail them back and I can start welding things back together.

It's not going to be pretty; with all the welding all over it, it's going to be a FrankenHeader. But if it works, hey... a little cosmetic grinding, maybe a ceramic thermal barrier coating, and it'd look a lot better.