HT front mount?

Discussion in 'Frame Mounted Engines' started by Drunkskunk, Mar 28, 2010.

  1. Drunkskunk

    Drunkskunk Member

    I'm trying to mount my Skyhawk HT to my frame with a SBP shifter kit. the back mount is set, but the shape of my frame means the front mount sits on the frame at an odd angle. I can't realy mount the motor on the bike this way, as the bolts would break, and I would rather not drill any holes through the frame.

    I figure this has to be a common problem, so what solutions have people come up with for making the mounts work?
     

  2. AussieSteve

    AussieSteve Active Member

    I bent a piece of 1/8" plate and bolted it to the motor, as shown below.
    Keep in mind, too, that with a shift kit, the engine needs to be adjusted upwards from time to time to keep the RHS chain tight, so you'll also need to add spacers between the frame and mounting to suit.

    [​IMG]


    ... Steve
     

    Attached Files:

    Last edited: Mar 28, 2010
  3. retromike3

    retromike3 Member

    Warring :Don't drill the frame

    I drilled my first motorbicycle frame and the engine vibration cut though it like a hacksaw. I was following the manual I downloaded from the folks I got my kit from. U blots and plates are a much better idea.

    Mike Frye
     
  4. AussieSteve

    AussieSteve Active Member

    Yep, I drilled mine and now have to live with it. (Hasn't cracked yet, though, after 500km.)
    That's why I recommended a 'U' bolt.
    (My kit instructions also suggested drilling.)
     
    Last edited: Mar 29, 2010
  5. retromike3

    retromike3 Member

    Keep a good eye on those bolt holes. Mine looked good until about 400 miles and then RIP seat tube cut in half. Maybe it will hold up better with a plate bolted to it instead of a motor bolted directly to it, like mine was.

    Mike Frye
     
  6. AussieSteve

    AussieSteve Active Member

    Yeah Mike, I inspect the downtube for cracking before every ride.
    I went one further, though, and made two extra 2" x 1/8" square curved plates, one for each side of the downtube, with a square of tube rubber under each and an 8mm high-tensile bolt through the lot. So far so good. It's a pretty sturdy setup, so hopefully my frame won't crack. Time will tell.
    To adjust the shift kit chain, I use more curved plates, slotted right to the end for easy fitting and the main mounting that bolts to the engine also has a closed slot for adjustment. (Not as complex as it sounds.)
     
    Last edited: Mar 29, 2010
  7. Ghost0

    Ghost0 Guest

    We sell a front mount similar to AussieSteve's that is no muss no fuss, install and go.
     

    Attached Files:

  8. AussieSteve

    AussieSteve Active Member

    I like the look of those mounts, Jim. I would have bought one if I hadn't drilled the frame.
    It looks like it would be easy to fit spacers for RHS chain adjustment, too.
     
  9. Drunkskunk

    Drunkskunk Member

    That will work.
    I like the sbp kit you have but was looking for something fast and temporary. I plan to weld a mount to the frame once I get the initial setup working.
     
  10. Ghost0

    Ghost0 Guest

    Welding the front mount to the frame is not advise able with the Shift Kit. A solid front mount will not allow you to adjust the jackshaft chain tension as your front mount essentially has to be able to pivot to allow the rear of the engine to move up and down. This why our front mount works is that it allows the engine to pivot using the inherent flex of the steel.
     
  11. Drunkskunk

    Drunkskunk Member

    I've got a couple plans to take care of that. the mount would be adjustible. But first I need to get this thing working, so a temp mount was all I needed.

    On a side note, Have you considered making a Shifter kit that didn't bolt directly to the motor? This kit is well put together, and would fit 4 or 5 of the frames I have, but the bike I chose has been a bit of a nightmare to make it work. however, it looks like it would have fit perfectly if I could have bolted the jackshaft behind the crank and just used a chain tensioner with the motor mounted as a normal HT motor.
     
  12. Ghost0

    Ghost0 Guest

    Well there are forces at work that just don't allow for that type of mounting and it would lose some of its ability to be universal. The "Requirements" page on our website says that it will fit a standard "V" frame mountain bike and most cruisers frames. If yours is other than those it is a "use at your own risk" kind of deal. BTW what frame are you using? I might be able to offer some mounting options for you.
     
  13. Drunkskunk

    Drunkskunk Member

    Some kind of Columbia frame. Year and type unknown but odd parts like a 19mm seatpost make me think it's pre ww2.
     
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