Custom made street bike header

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This is one of my first big projects I made about 1.5 months after getting my welder. 78 kz750 with a few mods done by me. This header was made from all straight piping. I made all cuts on a chop saw. No back purge. Steped header that made more power and leaned the motor way out wich is what I was trying to do bc a couldn't get the jetting any closer without running some alcohol in the tank. I had to bump up main jet after this mod. I was pretty happy with outcome. There were no drawing or anything I just build stuff as I go.
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Reply:if I remember right I think the intake port went from 87cc to 92 or 93cc. I rode it before rejeting and it ran crazy lean. There was detonation all over the plug. Of course I jeted up
Reply:this is what it looks like now with the ****ty bbq paint I used. It is equal length. And I kept adding collector length and hand made a cone on the end
Reply:I'm surprised i had a 1978 kz 650sr and it was a 4 cyl, even the 79 550 were four cyl. was thinking only yamaha were 650 twins... i learn new stuff every day lot of work what you did, the sound must be loud lol... considering equipment available you did very well.
Reply:i made this for the chop saw to make the collector. First time doing this
Reply:the annoying part was cleaning the inside of every piece with a knife and grinder
Reply:this this is the part that holds the header on the head. These come in half. I don't have many fancy tools yet. I need to build a real bench so I can start making money welding people's stuff up. These are 3/8th AL
Reply:this goes in the head but I put it on my Machinest lath so it would be flat
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Reply:Pretty nice job Moto'.What material did you use and what settings on your welder?Did you go with a different coating?Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:Nice job on the header,but your beating a dead horse trying to get much power out of that 750 twin.  The smaller Kawi kz 650's made a ton more power than the twins.
Reply:Originally Posted by dubl_tPretty nice job Moto'.What material did you use and what settings on your welder?Did you go with a different coating?
Reply:Originally Posted by CreteNice job on the header,but your beating a dead horse trying to get much power out of that 750 twin.  The smaller Kawi kz 650's made a ton more power than the twins.
Reply:I like it! I have been really wanting to make a collector, just never had time to figure it all out.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:The picture is right there. I depends on a few things. What machine do u got? U can always make it smaller and cut it up
Reply:What angle is it on? And how do you know what angle to cut it based on the flange you plan to use?Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Sounds like ur talking turbo header. I would think the straighter angle the better. Pry depends on turbo size. Collector size is mainly based on rpm range and hp  and how many pipes u got going to it.  Also header length and collector length play a big roll. Larry muaex makes a program called pipe max wich takes the guessing out. You will see guys polishing there collectors to a mirror wich is a huge wast of time. Same with the ex port just leave the carbide marks in the bc it will turn black in 2 sec. Unless ur running alchoal. Same with the intake. Longer intaker means lower rpm power band
Reply:Fun project. I've made a couple motorcycle headers myself for my bikes, here's an old pic of one of them. I used mandrel bends instead of pie cuts though, I don't have that kind of patience  Last pic just shows how it looks after a few miles, now that it's been through a few heat cycles. Not everyone's taste, but I love the look personally. Attached ImagesGive me fuel, give me fire, give me that which I desire.
Reply:That looks sweet primetime!! What did it have on there before this? And how did it change ur power band? What size collector? Is that more of a glass pack design. If not that could be bad bc that should be a high speed area. I like the un painted look to myself! But mine was steel
Reply:Lets put up some sound and take off videos
Reply:Thanks. It had my first ever attempt at a custom exhaust before this one, that I made a few years ago. The old one was mild steel, under header wrap.I actually tried to do my homework & match the runner lengths to where I wanted the powerband to be, on the exhaust & intake I made too. It made decent power considering that it only revs to 5,000 lol. The muffler is just a straight through louver core with some "chambers" around it, you can still sort of see the weld mark from the third "end cap" I used to separate the chambers. No packing material. The collector has 1.75" diameter inlets, 2.5" outlet. There is more power to be had with a better flowing muffler I'm sure, but I love how it sounds so I have no desire to change it. It's actually not very loud, until the throttle goes wide open anyway... Then it gets nasty  Attached ImagesGive me fuel, give me fire, give me that which I desire.7 hp is a nice jump. But u got 2 different lengths and they look pretty far off. I bet u could make way more bottom end with more collector length. But sounds like u don't wanna touch it. It fits the bike well
Reply:What's ur AFR? U wanna be around 12.6 under wot. And did u throw more fuel at it somehow?
Reply:Originally Posted by motolife3137 hp is a nice jump. But u got 2 different lengths and they look pretty far off. I bet u could make way more bottom end with more collector length. But sounds like u don't wanna touch it. It fits the bike well
Reply:I have never heard of 30% Gain from intake and ex. Unless u got a hidden turbo. Did u make the intake between the throttle body and intake port or just the air cleaner to butterfly?  That thing must of been super lean and restricted to get a gain like that
Reply:I bet u don't ride the bike in the rain with the filter exposed like that. I bet u could pick up 3 or 4 hp by making a shield on the backside of the filter. Bc ur pulling in hot air. Every 10 degrees less u pull in there makes about 1% more power