rear suspension #2

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by scratchbuilder, Mar 14, 2016.

  1. scratchbuilder

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    The beginnings of a new rear suspension build. I think this is a better looking front clip than the cruiser frame. I'm going to use short cranks to keep it low.
     

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    #1 scratchbuilder, Mar 14, 2016
    Last edited: Mar 14, 2016
  2. Tony01

    Tony01 Member

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    Yeeehaw!! This is going to be a sweet build can't wait to see it done.
     
  3. scratchbuilder

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    Me too..this one got a lot of welding. This one is staying. That last Briggs made a believer out of me... So as the addiction grows I couldn't say no to 5, five Briggs for 5$ each!! No carbs....idk....3 have spark..2 no mag/coils. I'm gonna run the center pivot on the girder through the seat tube. Less brackets to make. And its place's the shock at a good place for engine clearance.thx 01..
     

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    #3 scratchbuilder, Mar 14, 2016
    Last edited: Mar 18, 2016
  4. magna_503

    magna_503 New Member

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    I thought the v2100 was an aluminum frame, and not steel. I guess the swing arm is steel???
     
  5. scratchbuilder

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    The v21 is alum. what i do is use a steel donor dual suspension and cut tthe bb with the swingarm mounts out of the bike and weld the mounts to my frame..in the thread 'rear suspension' there are pics of how i did that marriage.
     
    #5 scratchbuilder, Mar 14, 2016
    Last edited: Mar 15, 2016
  6. scratchbuilder

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    Motor mount going in. Cutting into the down tube worked well on the last build...sooo, doing the mm this way gives 1 1/2 more space for js. A pic of spare parts and next in line. The 3.5 hp has a short 3/4 shaft if i use it id have to do a js clutch. Ordered gaskets and rings for the engine im using now(3hp).
     

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    #6 scratchbuilder, Mar 18, 2016
    Last edited: Mar 18, 2016
  7. curtisfox

    curtisfox Active Member

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    Looks like a lot of Briggs powered bikes coming, Looking good ..............Curt
     
  8. cannonball2

    cannonball2 New Member

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    Wow this is killer! A wild man with a welder!

    You gonna run the same type of carb?
     
  9. scratchbuilder

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    Lol.. Ive got a helmet sticker with a crazed looking dude saying..."must weld". Tried to order bearing hangers ....not..BMI had em... 3$.... and only 13$ shipping..say what...got the wide bb & parts coming from Sbp. So a pic of my js carrier. I got a pz16 coming, i was gonna use on the honda. Ill try it . just for info. Hey my honda wont run right..when you hold the thottle at an rpm you want..it revs up..revs down..revs up ..revs down. Ive removed all gov. from inside...idk...
     

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    #9 scratchbuilder, Mar 19, 2016
    Last edited: Mar 19, 2016
  10. scratchbuilder

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    Thx curt..gonna take a lot of make-up to purty up my welds.
     
  11. cannonball2

    cannonball2 New Member

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    Wow, making it happen!

    I ordered and just got 2 hangers from BMI via ebay for $9 shipped. Looks like you have it handled though.

    Honda sounds lean maybe. Clean the main jet with wire or torch cleaners. May have a varnish build ring up that carb cleaner wont remove.
     
  12. scratchbuilder

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    Yeah..agk being out all the time affects all. On that honda issue...i put a nt carb on..same thing. Till i find a small honda racing mechanic...its out of sight..out of mind... Dang emotional buy...
     
  13. Tony01

    Tony01 Member

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    yeah BMI seems to make their money on ripping people off on shipping... two hangars costs $6 to ship priority with the flat rate box. I bought some stuff from them and it cost over $20 to ship something that would have cost me less than $10..
     
    #13 Tony01, Mar 19, 2016
    Last edited: May 9, 2016
  14. scratchbuilder

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    Glad to hear the build is coming! Im thinking of running my nexus 3sp. Im going to have 12t engine to 36 js to 12t down to the freewheel...thats where i dont know what to run back to the 18 on the hub. If i go 60t (#35) then 24 back to the 18 hub. Got any idea if that would work. I have no idea what 1st ratio is on the nexus . with a 212..2speed you'll be able to take the freeway...lol
     
  15. Tony01

    Tony01 Member

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    Haha freeway!!! LOL!! . I'd like to build something comfy enough to ride to the races... 450mi from here.... You know... Road trip...

    The hardtail made my back ache after 50mi days.

    Dunno about the nexus but you won't have engine braking with it. The sturmey s3x you will and it's a 60% jump from first to top gear.

    With the 60 it will be 5:1 at the engine but then you will overdrive it to the hub. Maybe a 11 instead of the 24 that will give 9 in nexus direct drive.
     
  16. cannonball2

    cannonball2 New Member

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    About the IGHs I run both the Nexus and the SA S3X.

    The Nexus has direct drive in 2nd with a .733 reduction in first and a 1.36 OD of 2nds direct ratio.

    The S3X has 3rd as direct are the other ratios are lower. It is nice to have engine braking this hub gives. Plus it will drive in any direction.

    For a Nexus build if you ran a primary of 11t/25t a secondary of 10t/44t top speed at 4k rpm would be 40mph, 52mph @ 5k rpm. This gives a low ratio of nearly 14:1 for take off.
    To lower the ratio add teeth to the primary jackshaft sprocket. Remember a stock CG sprocket bolts directly to an 18t sprocket on the Nexus.

    The S3X is not so easy dealing with the sprockets as the center is larger and the sprockets have a different spline set up. It is tough, handles pedal starting a CG with no issues. Its an excellent hub! Worth the extra $$ and time need to make a sprocket for it. The Nexus is more fragile but I feel will last with care. Plus they are cheap as dirt if you shop around.
     
  17. scratchbuilder

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    Cb2..those sx3's...130$...I'll try the nexus..and be gentle. Then again...after experiencing engine breaking on the last Briggs..i liked it.Good info 01.. now I have a starting ratio from experience. If.. the nexus don't hold up..maybe a freehub with just 2 gears. They sell a 1gear swap out..so why not remove a spacer add another gear. Maybe I could use single speed chain too.
     
  18. scratchbuilder

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    Into the wind...making the mm & js plate ...pic coming
     
    #18 scratchbuilder, Mar 20, 2016
    Last edited: Mar 21, 2016
  19. scratchbuilder

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    Well, scratch is scratching my attempt at a js carrier. I'll have bite the bullet and wait for carriers.....and pay the 13$ shipping. But my way will not work. I need the space that the 1 1/4 pipe takes up. Running the js hangers will give me another 1/2" of adjustment for chain tension. Its a good thing....that way i dont rush the build. zpt
     
  20. scratchbuilder

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    Awlrigght. ebay.. 2 of the agk type bearing hangers 9$ free shipping. Interestingly the seller is 'stevbmi'..could be bmi..on their site it was 13$ for shipping..thx for the info on ebay CB2
     

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