Rally 1200 Sportster! formerly The GO-SPORT adventure!

Discussion in 'Some Assembly Required' started by tobiism, May 26, 2016.

  1. AK650

    AK650 Long timer Supporter

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    When we were talking bikes and bike weight, the 315# bike may have been one of Mert Lawwill's bikes(not Richards). He went to great lengths to shave every ounce possible off the bike. Lightest Sportster I'ver ever heard of.
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  2. villageidiot

    villageidiot Long timer Supporter

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    I thought it was Richards, but yeah.

    The crazy lightweight bike we were talkin about was John kocinski, and his “cr250”

    I dunno how you’d get a sportster to 315lbs. And I don’t have the titanium budget to try.

    1C32AEAF-AB8C-4D16-93CC-018CF24DF8D7.jpeg
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  3. tobiism

    tobiism Long timer Supporter

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    "Adding lightness" becomes SUCH an obsession!
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  4. Webman

    Webman Long timer

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    I hear you. I’d be better off finding a diet that works. I should be cutting about 30lbs. That would be much cheaper than titanium, but titanium works RIGHT NOW! :rofl
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  5. tobiism

    tobiism Long timer Supporter

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    I went on the keto diet in January and I lost 50 lb in 2.5 months. If you are looking for a diet that works I highly recommend it!
    Screenshot_20190531-120036.png
  6. AK650

    AK650 Long timer Supporter

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  7. AK650

    AK650 Long timer Supporter

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    Damn straight......I'd be better off doing the same as well!
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  8. tobiism

    tobiism Long timer Supporter

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    Okay this bike got sold a little while ago. It was just getting too heavy and it wasn't turning out the way I wanted. But I would like to start over and I'm thinking of going in a different direction. What I would really like to end up with is a rally style bike and I'm thinking of using a KTM 690 gas tank subframe seat section along with a tube trellis style frame raked out to 27 degrees. 4 gallons of gas would be ideal. As light as I can get without going all titanium is the goal.
    Monoshock aluminum swingarm
    Aluminum oil tank
    YSS forks
    18x21 warp 9 wheels
    Screenshot_20210407-190032_Chrome.jpg Screenshot_20210407-191253_Instagram.jpg
  9. JagLite

    JagLite Long timer Supporter

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    Most excellent plan!
    I wanted to build a true Dual Sportster many years ago but once I went through making a list of things to dump, replace, or change the only thing left was the engine, and it would get many changes too.

    I think starting with a tube frame Buell (with engine) makes the best of what's available at reasonable prices.
    That's going to be the strongest, lightest frame unless you go for a custom frame for a lot more money.
    Good wheels, brakes, forks, sock, and aluminum swingarm will help keep the weight down and if you go with the under seat style tank it will help keep the weight lower for better feel and handling. :thumb

    I had decided to go with a Bottpower frame:

    [​IMG]

    Here is the cad rendering of the spine frame:

    upload_2021-4-7_18-43-8.png upload_2021-4-7_18-43-38.png

    And a couple welded up:

    [​IMG]

    He did a finite element analysis as part of the design and the spine frame is excellent.

    They sent one to race Pike's Peak:

    [​IMG]

    The price for a custom frame is reasonable...

    upload_2021-4-7_18-49-49.png

    But, if you can find a good tube frame Buell you will be way ahead.

    Can you just imagine an ADV Bottpower though? :raabia
  10. JagLite

    JagLite Long timer Supporter

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  11. tobiism

    tobiism Long timer Supporter

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    Wow those are super cool! I have thought about doing a spine frame like that and I did find a good price on a Buell frame but I've also considered making my own. The only challenge with the Buell frame is that I would want to convert it over to rigid mounted instead of rubber
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  12. JagLite

    JagLite Long timer Supporter

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    I had to laugh when this bike showed up in my email box today since we were discussing building a GOOD Sportster:

    [​IMG]

    The builder says:

    To build a nice Harley, you buy a Harley, keep the VIN number and reg, and throw the rest away. This bike says it started its life as a Sporty in ’02. There is truth in here but front to back, the cycle parts of the machine include:

    • Maxxis tyres and Excel Takasago rims.
    • Motocross shocks from a 450 Suzuki.
    • Beringer brakes.
    • Magura brake master cylinder.
    • Flat tracker bars.
    • The tank is handmade in steel.
    • Seat unit.
    • The frame is a Sporty but it has had to be cut and braced to enable the head angle.
    • The pegs are motocross pegs.
    • The swingarm is by Metmachex.
    • Nitron shocks.
    • DID chain.
    • Rear hub has an Excel cushdrive. I grew tired of ripping out the standard Harley hub.
    • Mert Lawwill provided the heads – not available now.
    • Cylinders, pistons, pushrods, ignition module, etc. from NRHS – speak to Daniel Dunn.
    • Dell’Orto carbs.
    • The oil case was cut down.
    • Derby cover engraved with my family crest.
    • An alloy oil tank was fabricated
    • Screaming Eagle oil cooler.
    • Supertrapp exhausts.
    • K&N filters.
    • The set up should be good for 115bhp, but for longevity I have wound the revs back and I run it at 90bhp.
    More HERE


  13. tobiism

    tobiism Long timer Supporter

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    Wow! What a beast!
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  14. tobiism

    tobiism Long timer Supporter

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    Got back to work on this guy. Cut a frame up so I could set it up for the dimensions I want. Frame has been de-raked from 30 to 27.5*. Neck has been raised about an inch. Looks like I will have to use a PDS shock setup keep the overall wheelbase of the bike where I want it. I'm planning on using a KTM 690 rear subframe / fuel tank so don't want to go with dual shocks.
    Next item on the list is to take the Caps off of the fork so I can raise the wheel up and make sure it doesn't hit the frame. 20210417_164015.jpg 20210417_193515.jpg 20210417_193528.jpg 20210417_193522.jpg 20210417_193539.jpg 20210417_193547.jpg 20210417_193549.jpg 20210417_214148.jpg
  15. JagLite

    JagLite Long timer Supporter

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    NOoooooooooo!!!!!

    [​IMG]

    :2cry




    Ahhhhhhh.....



    :hide






    YES! :thumb

    [​IMG]




    Whew!
    :knary
  16. tobiism

    tobiism Long timer Supporter

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    Haha. Yeah it was tough to cut that frame up but I know I'm never going back to street riding so it was just taking up space. And it's titled. So perfect fodder
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  17. tobiism

    tobiism Long timer Supporter

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    Alright we are in business with the front end. No contact on compression.
    Spine will be fabricated this week and the swingarm will get lengthened 2" and lightly braced in preparation for PDS shock arrival with 10.8kg(!) Spring.
    Swingarm pivot will be refabricated 1.5" lower
    Gas tank will be the seat/tailsection.
    Forks will actually be 48mm ktm
    Wheelbase approximately 63"
    20210418_210229.jpg
  18. AK650

    AK650 Long timer Supporter

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    You doing an oil in frame spine, or using a conventional oil tank?
  19. tobiism

    tobiism Long timer Supporter

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    I'm using 1.5" Dom for the spine so I don't think I can get enough volume there. Was planning a skidplate oil tank occupying the space in front of the primary
    Screenshot_20210420-064859_Gallery.jpg
  20. Ozarkroadrunner

    Ozarkroadrunner Been here awhile

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    Good to see you back!
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