homemade headers/exhaust

The last bike I bought had on it what was obviously a homemade 4 into 1 system. I never ran it so I dont know what the performance was like but the appearance was quite frankly a discrace to all kzs everywhere and made me upset just to look at it.

I have built some headers before on some race cars, mainly because we couldnt buy anything to fit and they worked pretty well, BUT, we had mandrel benders, lots of tubing, gonna need it cause you are going to trash a bunch of it, tig welders spare heads to use as jigs and a bunch of time.
one thing the TV, guys dont do is clean up the inside of the tubes, if you have rough areas then the flow changes and it will hurt preformance.

if you have a engine on a dyno, change headers, same make, to a set that is rusty on the inside and try to figure out why you lost 12hp,

Hi fische,

I tried to reply to your post this am but the board timed out and I lost a hundred words, give or take a few.

Stainless steel is the material. You can buy many diameters and thicknesses. I used 1 3/8" dia., .035" wall thickness for my coolant tubes. You can even get pre bent "J" bends which you can cut to any angle you wish. Next you need a tig welder, the machine and the operator. I've been welding all my life and am passable at welding stainless tubing.

But the real issue is lacking a cornfuser with which to calculate the harmonics you will need several hundred iterations till you get it right.

Basically you've got two choices open your wallet way wide and build your own or take advantage of someone else's engineering and buy a premade system.

KZCSI

practice bending some 3/4" conduit till you come up with something that looks like what youre looking for then build it out of bigger tubing;)

how important are harmonics to exhaust headers? I read somewhere that with smaller engine sizes not outrageous rpms and a lowish compression ratio, (also stock cams so far) that air velocity is much more important. I'm not really looking for the ultra in high performance, I'm more looking for cheap, or cheaper, and the experience. If i made an exhaust system that performed at least on par with stock and cost $100 less then a new 4 to 1 I'd be very happy.

I'm also considering a 4-2-1 cause i heard it would give better low and mid range power, but seeing as everything else is stock I think I'll just go with a 4-1 for ease.

BSKZ650

one thing the TV, guys dont do is clean up the inside of the tubes, if you have rough areas then the flow changes and it will hurt preformance.

how do you clean up the inside of the pipe?

Also about heat transfer, thats more of an issue with material right? I figured I'd somewhat copy the 4-1 I've seen for sale new.

Also I plan on using stainless steal 'J' bends or 'U' bends, or whatever they are. I figure its gonna take a ton of tig welding but I think I might be up for the challenge. I need to find a tig machine to get a little practice on before I jump into this whole thing, its been a while since i tigged anything up.

Is tig welding aluminum harder than stainless steal? I only have experience with aluminum.

you definatly want stainless for everything until you reach the muffler, which can be aluminum as the heat is much less by then. you have the right idea, buy the u bends and cut them to the right shape. like stated, equal length pipes befor the collector is important. a 4-2-1 is supposed to have better midrange and a 4-1 better high end. I have also heard that pipes getting gradually bigger as they get farther from the engine makes more power, but i would wait till after the collector to do this so it will be easier to balance header pipes. so basically im saying make a megaphone system. you can clean up the inside of the pipes with a dremmel on short pieces, not sure how long ones are done though, maybe a snake type thing (think plumbing?) hell, since you are going through this much trouble, you might as well make an undertail to really show off:P

welding stainless is a lot easier than aluminum.if you have access to an ac/dc stick welder with reverse polarity you just need a bottle and a stinger .make sure you weld in a well ventilated area stainless steel puts out really nasty fumes when you weld it;)

you could stick weld the exhaust pipe? i figured it would be to thin, just blow through or put way to much heat in the metal and cause a bunch of warping. I'll have to run down to my local welding supply shop and see what they have to say about it.

you use the reverse polarity setting on a dc welder.you need a tig torch and an argon bottle i believe it is,havent done it in a while.anyway you hook positive cable from welder to the end of lead coming from tig torch and hook your ground cable to the work like normal.make sense?

ahh yes i c, i misunderstood, its been a while since i was in a welding class

well what about using cast copper to make the header?

If your furnace is set up right its not too hard to melt
that would be a sweet look