MIG Welding an Exhaust Header - CB400T - Page 4
Close

MIG Welding an Exhaust Header - CB400T

This is a discussion on MIG Welding an Exhaust Header - CB400T within the Technical forums, part of the Caferacer.net Forums category; Irk! choppers are passe, you should stand up the rear end slide the fender forward and fit it with chains, that thing would make an ...

Page 4 of 4 FirstFirst ... 234
Results 31 to 37 of 37
Like Tree15Likes

Thread: MIG Welding an Exhaust Header - CB400T

  1. #31
    Senior Member TrialsRider's Avatar
    Join Date
    Jan 2011
    Location
    Ontario, Canada
    Posts
    5,168
    Irk! choppers are passe, you should stand up the rear end slide the fender forward and fit it with chains, that thing would make an awesome period hill climber.
    ... for a few good runs anyway
    irk_miller likes this.

  2. #32
    Senior Member woodsman's Avatar
    Join Date
    Mar 2016
    Posts
    1,426
    Gurgle, wa wa wa should only be heard out of kids at a beach.
    irk_miller likes this.

  3. #33
    jcw
    jcw is offline
    Senior Member jcw's Avatar
    Join Date
    Jul 2015
    Location
    chicago burbs
    Posts
    2,028
    Quote Originally Posted by DesmoDog View Post
    The link doesn't work for me so again I'm shooting from the hip here, but...

    Midrange rpm. Yep, you have to decide which rpm range you want the tuning to be effective at. And by that you're deciding where it will hurt you too. Boosting midrange equals longer lengths. Ain't gonna fit even worse than if you wanted to bolster top end.

    "cam angle of open on exhaust or BBDC"? I'm going to assume you have some sort of autocorrect going on with a couple typos there, because that makes NO sense. I get that it's a reference to valve timing? Yeah, that matters too. My guess is you haven't checked this, and don't really understand what it is (both figuratively and specifically). You have to know when the valve opens to know when the low pressure pulse should be there. So you need to know the cam timing, the speed of sound in the exhaust, and the rpm you want it to be effective at before you can calculate a pipe length. You're guessing at any of those? Then just make the pipes fit the bike and look "right".

    Anyway, it's really late and I'm rambling. Sum it up to say, if you don't KNOW the cam timing and the exhaust temps, your calculations for exhaust lengths are simply guesses. You're fooling yourself if you think putting your guesses into a formula is optimizing anything. The calcs might give you a general idea of what to look for, but you're not maximizing anything. It ain't that simple. There's a reason the serious guys use software that costs thousands of dollars a year to license to model this shit. And then go test it all on a dyno when they're "done". Then repeat as needed.
    To add to this...
    I use this program- Pipemax.

    PipeMax Professional Engine and Header Design

    Check out the data it requires
    Name:  PipeMax400Input.png
Views: 87
Size:  118.0 KB

    I could run one set of data for you if you'd like. Cause that's the kinda guy I am...

    I've run it dozens of times for my bike and the alternative links I provided to you give close enough results that it wouldn't make enough sense to spend $$$ for a backyard build street bike with a stock engine and OEM carbs. It simply wouldn't...
    besides resonance tuning works on a narrow range of rpms. it's not like a supercharger or displacement or compression ratio increase where you get gains throughout the rav range. We're talking a modest boost over ~1500 rpms
    for a racer, that might mean the couple 1/10's or meters at the finish line, but for a street bike? C'mon

    KISS
    Last edited by jcw; 03-04-2019 at 03:08 PM.
    540nova and jakejensen like this.

  4. Remove Advertisements
    CafeRacer.net
    Advertisements
     

  5. #34
    Senior Member irk_miller's Avatar
    Join Date
    Nov 2018
    Location
    Augusta, GA
    Posts
    178
    Quote Originally Posted by TrialsRider View Post
    Irk! choppers are passe, you should stand up the rear end slide the fender forward and fit it with chains, that thing would make an awesome period hill climber.
    ... for a few good runs anyway
    Ha! I really do want to try a few runs on the 1/8th mile drag strip near me.

  6. #35
    Senior Member TrialsRider's Avatar
    Join Date
    Jan 2011
    Location
    Ontario, Canada
    Posts
    5,168
    Quote Originally Posted by irk_miller View Post
    Ha! I really do want to try a few runs on the 1/8th mile drag strip near me.
    Too flat, motorcycles get way more fun as you approach vertical.

  7. #36
    Junior Member jotacorsa's Avatar
    Join Date
    Aug 2012
    Location
    between Santa Fe and Taos, , .
    Posts
    13
    like jcw i use pipemax
    i buy mandrel bends from a supplier like headersbyed and tack them with a MIG until the whole system is in place then gas weld as i find it difficult to go around a small thin tube with a MIG, keep it pretty and not blow holes through the metal...i simply don't weld enough to have that kind of skill. and a TIG is way out of my budget

  8. #37
    jcw
    jcw is offline
    Senior Member jcw's Avatar
    Join Date
    Jul 2015
    Location
    chicago burbs
    Posts
    2,028
    Tig used to be out of most peopke budget. But now with cheap but quality chinese tig machines welding has become much more accessible.

    I think a DC tig with almost all the bells and whistles can be had for around $500.
    540nova likes this.

Page 4 of 4 FirstFirst ... 234

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Similar Threads

  1. welding exhaust ports
    By roccitycafe in forum Technical
    Replies: 21
    Last Post: 11-07-2015, 03:09 AM
  2. Suzuki GS500 powered Drag bike project on mig forums.
    By nic579 in forum Vintage Motorcycle Racing
    Replies: 1
    Last Post: 08-03-2014, 09:58 PM
  3. TIG welding stainles header - filler Question
    By kerosene in forum Technical
    Replies: 8
    Last Post: 04-14-2010, 10:22 PM
  4. mig welding question.
    By pampadori in forum Technical
    Replies: 11
    Last Post: 08-09-2008, 09:24 AM
  5. Replies: 3
    Last Post: 03-10-2008, 11:42 PM