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My new 'homemade' headers, XJ750

Discussion in 'XJ Modifications' started by 50gary, Mar 24, 2021.

  1. 50gary

    50gary Active Member

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    My 4/1/4 steel, .062" wall, Ceramic coated. I built these for my '82 XJ750 Maxim. They fit well and weight 18# 12 oz. a bit more than I hoped for but they'll be durable.



    fullsizeoutput_f.jpeg fullsizeoutput_e.jpeg PICT0012.JPG
     
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  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Oh....please tell me that you're going to run with 4 outlets on her....
    So cool.
     
  3. Franz

    Franz Well-Known Member

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    How do you bend the pipes and measure everything so the system fits the bike?
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    does it allow for center stand or bike jack?
     
  5. 50gary

    50gary Active Member

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    Thanks for the kind words. Absolutely, the one back to four, that's my style statement. My inspiration for that was the business end of a Saturn Five booster Rocket. I bolted the system on late this afternoon all is well.
    Oh, I put the system on without packing the baffle, can't resist, I want to hear what will sound like straight through. I will definitely put the packing in after the trial my hearing couldn't take it.
    Cheers, 50gary
     
    Last edited: Mar 24, 2021
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  6. 50gary

    50gary Active Member

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    That's most of the work in exhaust, I took a bunch of precut bends and straight sections then cut and just tack weld them together to get the proper path, look, and hopefully equal length.
    Then I have a friend that's does race car headers and he did the bends, (mandrel) he's very good and has all the equipment and tooling required. I wanted to just hire him to do the whole system he said no, just make the prototypes and he bent the head pipes. I had scratch built two other four stroke systems prior to this project so I knew what to do I was trying to be lazy. ha ha.
    So I did. The head pipes are nearly the same bend as the Yamaha stock, but a closer fit to the bike and larger diameter tubing 1.625" O.D. outlet is 3" then into the 1/4
    I made the take off slugs (as I call them) from the head out into the first bend, nice to have lathe, I made them a bit heavier to help draw out heat, I don't run a exhaust gasket with a machined piece mating to the port is a good seal again sinks out heat and
    a smoother path, race car stuff.
    Cheers, 50gary
     
    Last edited: Mar 24, 2021
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  7. 50gary

    50gary Active Member

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    No,center stand and no paddock stand (yet). I'll make one for sure just haven't gotten around to it as yet.
    I don't like center stands, too heavy, every 6.4# equals one hp. Like I say I'll eventually have a paddock stand
    for working on the bike and winter storage. Makes sense. Next phase is the carburetors.
    Cheers, 50gary
     
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  8. Franz

    Franz Well-Known Member

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    Looks great Gary l would like to try a make an exhaust system like that. It will sound great, l like the four exit pipes.
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    at what point does the 6.4# rule stop. not disputing it just wondering
     
  10. XJ550H

    XJ550H Well-Known Member Premium Member

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    if he can get the flames it would really cool
    [​IMG]
     
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  11. 50gary

    50gary Active Member

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    Well... I've thought about that. It has to be an algebra problem as the power to weight scale will change with each unit of weight you remove.
    As the bike gets lighter, it has less effect per pound but greater effect over all, diminishing returns, until you're a moto gp bike and can no longer (easily)
    remove weight. Stock bikes are easy at first. For me I want fenders and a muffler not a stripper, but that doesn't mean they can't be reasonably light?
    Cheers, 50gary
     
  12. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    My Great-Uncle worked on assembling the Saturn V engines. He figured out a faster way to get the job done and got to visit with the FBI about it. NASA adopted his changes to the routine once it was determined that he wasn't trying to sabotage the program.
     
    Last edited: Mar 25, 2021
  13. 50gary

    50gary Active Member

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    That's cool about your Uncle, not so cool about the F b I
    Cheers, 50gary
     
  14. Simmy

    Simmy Well-Known Member

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    @50gary when do these go into production?
    Mark me down for one please, LOL.
     
  15. 50gary

    50gary Active Member

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    To be honest the proper way to do this would be to take this original set back to the Shop that bent the header tubes and job the production out to him.
    He could make them quickly and efficiently 50 years of experience does that. Father and now son that's been their only business. I will perhaps by summer
    put the bike on the dyno to see how much power I've lost ha ha?
    Cheers, 50gary
     
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  16. Dave in Ireland

    Dave in Ireland Well-Known Member

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    A 4-2-1 should pull nicely, I think.
     
  17. 50gary

    50gary Active Member

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    Let's hope so? I'll be happy if it works as well as factory stock. As mentioned a bit lighter weight, a more individual look, along with the all import sound.
    The voice of the motorcycle.
    Cheers, 50gary
     
  18. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    And here we have it, today's big winner!
     
  19. 50gary

    50gary Active Member

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    . This was what gave me an idea.
    Hope this link works? This is Magnificent in all respects, My comment is still up 11 years later. Spellbinding.
    Cheers, 50gary
     
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