Who to talk to about exhaust modifications?

I have a dual exhaust from a KZ900 that I want to use on my 1981 KZ1000. On my newer bike there is a plate on each side that the foot pegs mount to. This plate has an upward slope on the back side and I would like the exhaust pipe to follow that line. If I shorten the connection point between the header and muffler by about 1.5" then the hanger on the muffler will line up with the hanger point on the side plates, and the end of the muffler will not interfere with access to either the axle or shock bolts, so the fit seems like it would be really good here. First question... will shortening the end of the header pipes have any negative effects on the exhaust?

Second question, and probably the hardest... To get this change of angle I would need to put about a 10-degree bend in the end of the header. From what I've seen at regular muffler shops, their machine would put a crimp in the pipe, creating a bit of restriction. I'm guessing this would definitely have a negative effect on the exhaust? If that's ok then I'll go with it, but otherwise what other options might I have that won't cost more than the pipes? The only other thing I can think of is cutting out a wedge and re-welding the pipe.

Pictures of bike , brackets and pipe would be helpful
Mandrel pipe bending is a possibility, but without pictures I may be very wrong
Dave

I grabbed some pics after messing with the starter problem, hopefully this gives you an idea.

So this is how the pipes are hanging on the bike at the moment (literally hanging because I wired them in place so I could try and start it). The idea would be to bend the header just in front of the muffler clamp, far enough up that the muffler itself would still be able to clamp onto a round section of pipe.


Another angle...


Here's another shot I took a few years back. The pipe is round for most of the distance, and only flares just as it is meeting up with the dual pipes. I believe the spot where I would need to put the bend is still round, so while a mandrel bend would certainly be ideal, I've never found anyone in the area with the equipment to do it.


So as I mentioned, would a muffler shop bender put too much of a restriction in the pipe because of the way they do their bends? Is it possible for me to do anything at home? Note that the chrome finish will be blasted off later so mig welding is an option.

Snowbum BMW motorcycle --- Encyclopedia.

Snowbum BMW motorcycle --- Tuning: Intake and Exhaust Systems.

Snowbum BMW Tuning: Intake and Exhaust Systems: Addendum #4:
The old 'bible' book on tuning. Still quite good, even now:
"Scientific Design of Exhaust & Intake Systems"; Philip H. Smith and John C. Morrison.

Motorcycle exhaust pipes are generally double walled and thus nearly impossible to bend, cleanly anyways. In any event, even if it could be done, the chrome plating would not like that process at all..

I just noticed what you said about not being concerned about the finish, so cut and weld might be the best bet for what you're looking to do. Personally, I'd just whip up some sort of brackets to connect the pipe to wherever you're trying to station it to.

@madmatt1 -- it's not about trying to find anchors for the pipes, that part is easy to fabricate. The goal here is to change the angle of the pipes as they come out from under the engine. Instead of going straight back as in the picture, I want the pipes to come up to around the lower rear shock mount.

One advantage of going with welding... the muffler has quite a bit of open space before it hits the packing. If I made the change there, it would give the same profile but allow the muffler to sit about an inch lower, giving more clearance around the rear foot peg. The down side is that the flow from the header would no longer be centered when entering the muffler, which I imagine would have a negative impact on the exhaust performance.

you might find something here;
www.epi-eng.com/piston_engine_technology...ystem_technology.htm

So I whipped up a mock-up of the plan with my awesome (or not) photoshop skills to show what I want to do here. Ignore the bottom pipe, it's the angle that I want to achieve. It *should* just be a matter of cutting out a 10-degree V, then welding the muffler back together again, I think?


If I wanted to get really crazy with it I could calculate the volume of the wedge I'd be cutting out, then add a short piece of straight pipe between the welds to recover that volume, but I think we're only talking about a couple of cubic inches and I would bet people have made far more radical modifications without affecting how the engine runs.