BTR leaf spring build

Discussion in 'Antique Motorized Bicycles' started by james65, Dec 21, 2011.

  1. james65

    james65 Member

    Although my BTR may be more of a cruiser due to the fenders, I have made a fork more fitting for a BTR.

    1. All moving joints are bushed.
    2. Spring connecting rods are adjustable to change spring preload'
    3. The pivot arms are reversable to change stiffnes of the desired ride.
    4. The adjustable spring connecting rods are built to be connected for leading or trailing setup.

    The existing fork will be used on a new Cruiser build.
     

    Attached Files:

    Last edited: Dec 21, 2011

  2. lanternman

    lanternman New Member

    Nice, did you have a longer axle? What did you make the spring from. I'm building a truss fork and may go for the spring. Louis
     
  3. james65

    james65 Member

    leaf spring & axle

    The axle being used is the standard axle supplied with the Husky wheel. The length of the axle is APROX 128mm.
    The inside useable space between the pivot arms is APROX 104mm.

    The spring was purchased at Harbor Frieght. I purchased the lightest trailer spring they had. I also ground it as shown, to make it have more give (that may not be needed).
     
    Last edited: Dec 21, 2011
  4. james65

    james65 Member

    Back from Christmas shopping with just enough time to get the fork painted. Holidays are screwing up the schedule!
     

    Attached Files:

  5. lanternman

    lanternman New Member

    Like the pictures. I am thinking of using a lawn mower blade for a spring. They are good steel and could temepered to make a spring. What do you think? Louis
     
  6. james65

    james65 Member

    Yes that sounds interesting. But with the amount of work getting the right temperment, it would be easier to buy a trailer spring. A single trailer spring cost about $20 and you can make two spring forks from it.
    A boat & trailer repair shop may even give you an old one.

    Plus with just half a blade that mower will run vibrate like crazy!
     
  7. lanternman

    lanternman New Member

    I like to try to make something out of junk. sometime it don't work.
     
  8. james65

    james65 Member

    Sometimes I make something into junk! Have a good holiday!

    Jim
     
  9. Sgt. Howard

    Sgt. Howard Member

    Garbage In Garbage Out does not nessisarily apply to motorbikes... however, springs are a tricky bit of buisness. Mower blades are closer to tool steel than spring steel, I would avoid useing them. Better off scrounging a boneyard- you might have to purchase a whole cluster, but even that ought to be cheap. Do golf carts use leaf springs? Never gutted one, don't know... seems the coiled spring variety of springer would be easier to replicate- but I gotta admit James- THAT looks sharp!
    the Old Sgt. :army:
     
  10. james65

    james65 Member

    leaf attachment point

    This is how the leaf is attached to this fork.
     

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  11. big kountry 75

    big kountry 75 New Member

    I like the truss style frontend an thats onr of the coolest I've seen yet an it appears to be reversible
     
  12. james65

    james65 Member

    Big K first thank you. Second yes it is adjustable and reversable in two ways.
    It can be set up for leading or trailing axle. The rockers can also be reversed to modify stiffness. The adjustable rods allow adjustable preload of the spring.

    Since those pictures were taken, I have added a second leaf. The second leaf is just for appearance and has no real effect on the operation.

    Jim
     
  13. Scootmeister

    Scootmeister Member

    Ah, American ingenuity is a wonderful thing! This looks just like a vintage motorcycle frontend, Good workmanship and good looks. When do you expect to try it out? Are you going to mount a headlight?
     
  14. james65

    james65 Member

    First thank you.
    Yes I have welded a bracket for the carbide light just haven't updated the photos. I store my bike in the basement near the heater so can't put fuel in it until the weather gets better to try it out.
    Plus I don't think I will be in any condition to ride for a while after watching the Pats loose to the giants!
     
  15. james65

    james65 Member

    Beautiful day, took it out for a test ride. Was amazed how good it rode. Much better than the rollfast coil spring that was on it. I had expected to have to modify to get it to feel right. However it seems great.
     

    Attached Files:

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