"Homebuilt" expansion chamber

Discussion in '2 smokers' started by dorkpunch, Jan 28, 2011.

  1. RecycledRS

    RecycledRS Along for the ride

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    I have to admit I thought it may be galvanized too. I got pretty sick after welding some of that stuff.
    #81
  2. Gramp-Z

    Gramp-Z Long timer Super Supporter Supporter

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    dorkpunch , thanks for this thread ! I had pretty much forgot about an expansion chamber I made in about 1973 for my TS 125 Suzuki . Wanted to get it producing some more power for longer highway trips . Built the pipe using drawings out of a manual for an X-6 Hustler (250 twin) . They were for making that bike a road racer . After building the pipe and making my own silencer , fattening up the jets . The engine got a lot narrower power band with quite an increase in HP . I did all the welding with a crappy little oxygen pellet / propane torch . Hand formed all the parts . Didn't turn out too bad for a 15 year old with almost no skills ! I will dig through some old photo albums and see if I can find a picture to scan . I'll be following along .
    #82
  3. jesusgatos

    jesusgatos fishing with dynamite

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    Made this pipe for my CR80 Expert / XR100 mini-trailbike by cutting/welding sections of 1.25" mandrel-bent tubing. Much easier than some of the 2-stroke pipes you guys are making. Stellar work some of you, others... A for effort. haha.

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    #83
  4. Brunow - 007

    Brunow - 007 Bantam Fever

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    Sweet! When i got the time ... i've got a new thing to do! :D
    #84
  5. Stagehand

    Stagehand Imperfectionist

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    Great thread, Dorkpunch. Great work on the welder. :deal
    #85
  6. dorkpunch

    dorkpunch Oops...

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    Still have some things to do, so dont think I've forgotten about this thread. I decided I didnt like the way the "bends" in the first cone came out, so I'm going to build a new one and cut/bend it up a little differently. Also still have to hang it on the bike somehow, but I'm trying to get my rearsets finished first cause the pipe will probably be hanging off of them. AND... been setting up a new toy that might come in handy for this project. Scrounged up a TIG welder. :deal
    #86
  7. david631

    david631 n00b

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    did you build this "pipe" before or after you got a PC? oops, my mistake, you had a computer. so what happened. did you honestly think it would work. I remember the 1st ex. chamber I built. it was for my 1964 yamaha yg-1t. ie., yamaha 80. I was taking metal shop at the time ( I think 9th grade)I got the dimensions from the local yamaha shop.(the owners son raced TT at Trojan speedway in so.cal.). laid out the cones, rolled them and welded the whole thing together. it went up the side of the bike with the stinger(about 5 in. long) going between the shock and the frame.it worked really well with good mid-range power. I'm not knocking your project. it just seemed like a lot of work for the results pictured here. oh, I have a question: how does your garage door work? I notice you have one of the springs on the center stand.QUOTE=dorkpunch;15055986]Dont know if this belongs here in old school, but since its for my '67 YL2, I figured this was as good a place as any.

    Little background. P.O.J. was my first ever motorcycle. Found it in a grain bin about 15 years ago. Finally got around to getting it road worthy for the first time ever last summer. Been puttering with it ever since. I needed something to do (yeah, right) and wanted to work on my welding / sheet metals skills and figured this would be a good project. My first attempt came out so-so. I used a free internet program to come up with the sizes for everything after I "blueprinted" my engine. Turned out like this:[​IMG]



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    While it worked okay and I learned a ton about cones, oxy/acet welding, and expansion chambers, it wasnt all that great. I had a TON of power at a VERY high rpm, but it couldnt get to that high rpm in the top gear. So, here we are at the second attempt![/QUOTE]
    #87
  8. dorkpunch

    dorkpunch Oops...

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    :dunno Didnt understand much of that... Like I said, its a learning experience.




    SO!

    Been a long time, but I redid the first cone, and changed the "curves" a lot. Worked out great.

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    Sorta mounted:

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    Built a sort-of isolation mount:

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    And a mounting tab.

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    Still need to run it and check for leaks, clean up some welds, and put some high temp paint on it.
    #88
  9. bk brkr baker

    bk brkr baker Long timer Supporter

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    Thanks for the daily belly laugh and thanks to you helpers for just being kids enough to try that.
    #89
  10. Cmiktm

    Cmiktm n00b

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    Very nice job for a cool old bike. Your pipe looks very close to the original gyt pipe. Would you be interested in selling the a cone template to help pay for your project. I recently acquired a yg1 that needs a new pipe. Would much rather build one like this then use a stocker. You can pm me if you want to work something out. Waiting to hear how it runs.
    #90
  11. dorkpunch

    dorkpunch Oops...

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    Let me see if I still have the files when we get back home next week... If not I can photocopy the cone patterns for you and snail mail 'em. If you think they are worth something great otherwise youre free to use them. The bike project is sorta stalled at the moment, decided to go a little overboard on the cafe project and my TIG welder isnt working out for the thin aluminum I'm using for the tank.
    #91
  12. Cmiktm

    Cmiktm n00b

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    Whatever you have would be great. Even if it's a copy of the cone patterns. Give me something to play with. Saves me from going out and getting the software at the moment. I need to upgrade my computer at home before I can do that. Appreciate the help.
    #92
  13. WIsixfitty

    WIsixfitty rock and roll the bones

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    did someone say hydroforming?:D

    That proces was invented and patetened in the early 70's by two men from a small shop just a few miles from me. The impetus was to supply snowmobile mfgers at the time with a quick and easy way to mfg expansion chambers with out the need for costly (time and money) tooling etc. Mercury snowmobiles in Fond du Lac, WI was the first OEM to utilize this process. Since then every major sled mfger at one time or another used this in production. Most of them were used in racing as it was an excellent development tool.

    It's an engineers dream because the turnaround time for a fit pipe could be as low as an hour or two.

    This process was purchased by my father in the mid 80's. Since then we've built thousands. We've also designed and tested thousands of different recipes on hunderds of different engines. We also updated the hardware and wrote a parametric program for drawing the actual pipe patterns to achieve better/closer tolerance than just about any handbuilt pipe can achieve.

    We still consult and produce custom systems.

    The more I learn about 2s exhaust the dumber I get. It's not a science.:1drink

    A recent just finished job on the dyno for vintage sled racing.
    It's an early 70's far from stock Yamaha 292 making close to 67hp at 8700rpm.
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    A pretty cool bike I did a few years ago.
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    /hi-jack, just figured it was some cool two-stroke stuff to contribute.:1drink
    #93
  14. dorkpunch

    dorkpunch Oops...

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    Cool! Plan on trying that some day, now I have a pressure washer so maybe in the future...
    #94
  15. dmcd

    dmcd Long timer

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    Wow, can't believe I just found this thread a couple of days after reading this.......

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    I didn't know who Walter Kaaden was, I didn't know the expansion chamber was based on the pulse jet from the v1 bomb! Or that Suzuki bought their 2 stroke technology from Eastern Germany.


    I have recently purchased a tig welder to have a go at making my own megaphones for my cb550, but was going to start with my yamaha v50 2smoke :-). Bills permitting, I am going to buy a small set of rollers this month.
    #95
  16. joexr

    joexr Banned

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    Ernst Degner was helped to defect from east Germany by Suzuki. Degner gave them Kaaden's secret plans. That was the rise of the 2-strokes.
    #96
  17. dmcd

    dmcd Long timer

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    What fascinated me was the fact that I have passed the Fernleigh Hotel in the Isle of Man many times, and my job involves working at the Belfast to Liverpool Ferry. Both of which were part of the story.
    #97
  18. Luke

    Luke GPoET&P

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    A cross post from my wr20o thread, since I was inspired by this one.


    This pipe is a mix of hydroformed sheet and pre-bent tubing. The design was made using the same 2-stroke wizard software.

    This is the second and third diffusion cones, the belly and the convergance cone of the pipe, made in a 180 bend to fit the bike. The paper is the flat template, the black pipe is 16ga mild steel and the silver one 18ga stainless.

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    Assembling:
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    On the bike:
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    I can definitely recommend it as a DIY construction technique. It's fun work, and it stretched my welding/fab skills.
    #98
  19. BillyGoat4130

    BillyGoat4130 Been here awhile Supporter

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    Luke...I really like how your hydroformed setup turned out. I just finished welding the last section onto a pipe for my project and I wished I had used your method now...

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    Lurked through this thread, it was a lot inspiration, so thank you for that :D
    #99
  20. Luke

    Luke GPoET&P

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    Wow. That's a lot of welding.


    Good thing you labeled all the parts. :)

    How did you design it?