Custom Frame For Thumper Motor

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by culvercityclassic, Apr 8, 2011.

  1. buck0

    buck0 New Member

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    WOW 52mph, smokin (^) Are you still using the 115 main jet from the race at Willow Springs?
     
  2. culvercityclassic

    culvercityclassic Well-Known Member

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    Dutchman; Still running the same setup from willow, only swapped out the rear sprocket from a 44 to a 50.
     
  3. Bike Monster

    Bike Monster New Member

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    some nice bikes... why dont you get rid of the master link and use a chain tool???
     
  4. nhssdf4

    nhssdf4 New Member

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    I love those hookworms you have on there... how did they work for you?
     
  5. nhssdf4

    nhssdf4 New Member

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    I read through this entire thread from beginning to end and it was quite exciting.... 52MPH! Thats crazy! To believe that you made almost everything yourself is quite unreal.... It is a very clean build and I really like the Frankenstein kinda inside with a cool metal outside. Absolutely a wonderful job and I hope to see it in person.

    Also for the fork, if you want a good for I would look at a Rockshox Reba or something of that nature if your not looking for a motorcycle-esk feel and they have high and low speed compression dampening for cruising or blazing down the roads. Another option would be a Rocksox Recon. Anything that uses air. Great build man, and referring to my previous post, I have lusted after those hookworms for quite some time. How did they hold up?

    Right now I am using a Michelin Pilot Sport 2.3 and I can almost knee drag on it.
     
  6. culvercityclassic

    culvercityclassic Well-Known Member

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    Thanks for the compliments on the bike; it has been a fun project. I am in the planning stages of a new bike for an up-coming race. I am thinking more along the lines of a modern board track racer powered by another four stroke. I am going to start the layout this weekend.

    The forks you recommend are nice and I might use them one day but at this time I am over-stocked with options, you would **** if you could see my surplus.

    As far as tires you have some of the best (Pilot) on your bike, the hookworms have worked well but then again I did not want to dump this bike on its first race. LOL
    I think one of my fellow racers and the winner of Willow (Magrider) was using Pilot’s.
     
  7. nhssdf4

    nhssdf4 New Member

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    The 2.5 is almost too much for any standard size frames, but the pilots have worked out wonderfully on mine. They are actually a little too big. I was watching a video of the race on youtube and there was a guy who looked like a blueberry, And it looked like he was running pilot's as well. Keep me informed on your projects as their badassery is off the charts. And as far as the 2 stroke vs. 4 storkes go, how did you keep up the morinis on the track?
     
  8. culvercityclassic

    culvercityclassic Well-Known Member

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    I think tire choice will be the main thing in our races, I went with the largest tire I could find with a good pattern and it worked for me.

    The bike I built did not have a problem with the Morini motored bikes. You can quote me on this: "The four strokes are going to dominate motor bicycle racing"...and the beauty of the four strokes is all the high performance parts available.
     
    #148 culvercityclassic, Jul 29, 2011
    Last edited: Jul 30, 2011
  9. bairdco

    bairdco a guy who makes cool bikes

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    welcome to the 50mph club! exhilirating, ain't it? ;)

    as far as your quote goes though, good luck with that. :)
     
  10. dmb

    dmb Active Member

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    this is great! kinda like the early days of hot rodding and motorcycles! cant wait for the next race!
     
  11. nhssdf4

    nhssdf4 New Member

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    I think that a two stroke 250cc motor would rip the spokes out of a set of wheels......
     
  12. msrfan

    msrfan Well-Known Member

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    Hey Jeff. I've been meaning to ask you about your fuel pump on your race bike. Is the gravity feed not enough pressure or volume? Just curious. Thanks. Dale.
     
  13. culvercityclassic

    culvercityclassic Well-Known Member

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    In regards to the fuel pump: I was following the recommendation from AGK web site: AGK - Fuel Pump Setup - Affordable Go Karts

    The other issue was how close the tank sits to the motor; I did not want to worry about a fuel issue. I feel this was an inexpensive upgrade and well worth it.
     
  14. msrfan

    msrfan Well-Known Member

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    Okay, thanks. I was just wondering.
     
  15. culvercityclassic

    culvercityclassic Well-Known Member

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    The latest addition to the bike is this 56 tooth sprocket; I am trying to get this motor to REV a bit more. The CVT when in full action lugs the bike a bit so hoping this resolves the issue. This new sprocket is as big as a PIZZA...

    I am also working on some type of chain adjuster to keep from losing it so often.

    O- and that other picture is just another Thumper... lol
     

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  16. culvercityclassic

    culvercityclassic Well-Known Member

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    I have been playing around with the bike a bit lately. Fixed some oil leaks, made some adjustments, and made a new exhaust. It has really killed me trying to come up with an exhaust that performs and looks right. Did a little research and this is my design, you could call it a staged exhaust since it gradually gets larger.

    I also worked on the fuel lines, the one on the bike did not hold up to our wonderful gas additive. I installed some hi-end fuel line that solved the problem.
     

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  17. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Nice pipe Jeff, there's no reverse cone hiding inside that 3rd stage is there?

    dnut
     
  18. tommyboy1442

    tommyboy1442 Member

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    amzing work brother, bad to the bone!!! itd be kool to see that thing with a full race motor on there runnin off alcahol turnin 15,000 rpms-lol
     
  19. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    A 4-stroke turnin 15K? OK then, better git werkin on an a-cohol race injun, it just stands too reason! lmaorotfupsidown

    dnut
     
  20. silverbear

    silverbear The Boy Who Never Grew Up

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    Good looking pipe!
    SB
     

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