Building My Own 4-1 exhaust

I was reading The Horse mag and they have a segment on making exhaust with lobster back bends. To me it would be a little more restricted then smooth bends so i got the idea of building my own 4-1 header. The idea would be to build this header so i could keep the stock jetting (this is just for the look not for performance).
I was just wondering what you guys opinion would be on building something like this. It would definitely save some money and it would be a one off part lol.

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If you have the fabricating skills/equipment...go for it! (just be ready to take orders!LOL) BUT! Regardless of whether you build it or buy it, if it is a 4-1 , you will have to re-jet...

Grumpy Ole Artist wrote: If you have the fabricating skills/equipment...go for it! (just be ready to take orders!LOL) BUT! Regardless of whether you build it or buy it, if it is a 4-1 , you will have to re-jet...

Is this automatically true, or does it depend on how the new system flows? Since esthetics are his primary concern, isn't It possible that the new system could have flow numbers similar to, or even lower than the stock system?

Certainly, no expert here, but IMO, unless one built it in such a convoluted manner (Extra "S" curves, back & forth to both sides of the bike, etc) as to use a LOT more pipe than your garden variety 4 to 1, or used super skinny, restrictive pipe, one would need to re-jet....As I understand it, having the four pipes connected at the collector (The so-called "tuned header" means runners of equal length, BTW) scavenges gasses from subsequent firing cylinders...It seems counter-intuitive to go to all the trouble of fabricating custom exhaust to not breathe freely, or to balk at re-jetting..."The RULE" (as I understand it) "Flow more air, flow more fuel" Again, not an expert, don't even play one on TV, but ya up your outflow, ya gotta up your inflow or you run lean and cook something.....If I am wrong, somebody PLEASE feel free to correct me! ALways ready to learn stuff!

The equipment i have the skills are questionable lol. I don't think it would be that difficult though. And i figured with the lobster back bends that since they aren't smooth it would restrict flow enough to be able to use stock jets.

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Rejetting really isn't a problem if i could narrow it down pretty close without having to buy a bunch of jets that i don't need. So say i was running a 4-1 header (any kind) with pod air filters on a 1980 kz1000 with VM26SS carbs what would be a good starting point for jetting?


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Regarding jet selection for "off the rack" headers, (Kerker, V&H, etc.) 650 Ed pointed out recently in another thread that there are hundreds of jetting posts to peruse...Will depend on type of exhaust? airbox with stock filter or K&N airbox filter? pods? With a custom fabbed header, others' advice probably won't apply...Mebbe pick up one of those snazzy "colortune" devices to fine tune jetting...If ya get em built, post pix, Please!

Exactly. It seems to me that there are far too many unknown variables at this point to be seriously worrying about jetting. Get 'em built and installed, and do whatever intake mods you have in mind, then you'll be able to tell about jetting. I've not tried the Colortune, but those who have seem well pleased with them.
Pics are required, aren't they??

Grumpy Ole Artist wrote: Regarding jet selection for "off the rack" headers, (Kerker, V&H, etc.) 650 Ed pointed out recently in another thread that there are hundreds of jetting posts to peruse...Will depend on type of exhaust? airbox with stock filter or K&N airbox filter? pods? With a custom fabbed header, others' advice probably won't apply...Mebbe pick up one of those snazzy "colortune" devices to fine tune jetting...If ya get em built, post pix, Please!

Custom pipes sounds like a good idea. I sold a set of flat black straight drag bikes from a KZ chopper about 10 years ago, I wish i had them now to cut up.
Yea! Staight pipes, Zommies! funnybike Injected pipes or some big diameter pipes like these.

Keep the headers around 27 inch long and 36 - 38mm diameter and the link pipe around 55 - 60mm dia and you won't go far wrong.

TexasKZ wrote:

Grumpy Ole Artist wrote: If you have the fabricating skills/equipment...go for it! (just be ready to take orders!LOL) BUT! Regardless of whether you build it or buy it, if it is a 4-1 , you will have to re-jet...

Is this automatically true, or does it depend on how the new system flows? Since esthetics are his primary concern, isn't It possible that the new system could have flow numbers similar to, or even lower than the stock system?

Not automatically true.

I suspect the muffler (or lack of it) would be the dominant factor.

Thanks for all the advice and opinions. I've never heard of the colortune thing before ill have to look it up.

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