Engine mounting problem at front

Discussion in 'General Questions' started by Irish John, Mar 5, 2008.

  1. Irish John

    Irish John Guest

    I'm wondering how to mount a 70cc 2-stroke on my Schwinn Alloy Seven Cruiser. The attached pic shows one method using a rear mount spacer as additional spacer on the front. Wonder if this might cause excessive vibration. I'd need to make special bolts to fit it on. Any help would be greatly appreciated.
    Irish John
     

    Attached Files:

    Last edited by a moderator: Mar 5, 2008

  2. azbill

    azbill Active Member

    that will work fine, as long as you remember that the exhaust might hit the frame then
     
  3. Irish John

    Irish John Guest

    Thanks, I'll do that

    Have already bent the exhaust to fit. I have to use an oxy torch to bend those things and it tarnishes the pipe. You ever bent them without using heat?
     
  4. azbill

    azbill Active Member

    I have had some luck bending between the rails of our pool enclosure (child-proof fence)
    a lot of 'little bit at a time' :D
     
  5. BoltsMissing

    BoltsMissing Active Member

    Not sure if this method will help your cause, it's the way I laid it out on the
    27" frame.
    It's the principle is what I'm getting at.
    The rubbers through the centre bolt and the frame are steering bushes.
    Motor Traders Part N0: A92-1
    The pic was taken before the bike was finished during measurments process.
     

    Attached Files:

  6. kerf

    kerf Guest

    I don't know if this would help anyone but something occurred to me about having to drill the frame for engine mounting. What if one were to bore the hole over sized to fit a spacer with an ID to fit the bolt. Have this spacer/bushing welded into the hole on both sides of the frame member. This would reinforce the frame at the hole and allow ample bolt torque to be applied without crushing the frame tube.

    For what it's worth.
     
  7. Irish John

    Irish John Guest

    Problem with rear mounting on a Giant Cypress.

    I'm mounting a 70cc motor on a Giant Cypress but the seat tube is very wide and the mounting bolts only fit around the tube if I force them (see how I've damaged the lovely paint finish on a new bike) I'm worried at the side pressure on these bolts when I tighten the nuts. I'll put a bit of neoprene stuff between the tube and the mounts or maybe blue gasket sealer.
    The front fixing will be as shown with a hole drilled through the tube and an 8mm dia. bolt with a big fat washer between the nut & the tube. This method has worked on my Merida Kalahary alloy MTB for 4 engines and 10,000 kms. Botlt has never fractured nor tube cracked. Hope it works this time. Anyone got any ideas for improvements?
    Irish John
     

    Attached Files:

  8. Hollywood

    Hollywood Guest

    Jonh, They have brackets for wide down tubes that use a u-bolt at livefastmotors.com.
     
  9. Irish John

    Irish John Guest

    Fixed the engine mounting problem

    Got the engine mounted today and it's perfectly aligned and as tight as ever but the exhaust needs to be bent again so the pedal doesn't hit it. Thought I had it bent perfectly. Can't bear to use an oxy torch again so I'll put it in a vice and use brute force a bit at a time. I need 3 feet of steel pipe that I can slip over the silencer to get leverage and I need a good nylon liner to protect the silencer from scratches. I notice that the chain stays are too fat too hold the tensioner arm so I'll get some longer bolts. Still trying to find out how I can get a grubee honda kit into Australia from the US. Anyone got any ideas. I'll try calling the Grubee 1800 number in the US tomorrow. The time difference makes it hard for me. Also does anyone have a Derny motorised bike (vintage French)? They were very fast motors and beautiful to look at. Here's a picture.
     

    Attached Files:

  10. cooltoy

    cooltoy Member

    I don't know if this may help you or not but I had to grind a bit off of the side of my peddle arm to clear the muffler. When I replaced the gasket one day, I noticed that I was rubbing again. that was when I realized that there is a fair bit of play with the muffler when the two nuts are loose.
     
  11. Irish John

    Irish John Guest

    Thanks Cooltoy,

    Do you mean that if I do up & undo the bolts the exhaust will change position slightly? The exhaust bolts or the engine fixing bolts or both?
    John
     
  12. cooltoy

    cooltoy Member

    Well, now that you mention it, both will help. I was talking about the two nuts that hold the exhaust onto the motor. There is so much play that it lets you move it around a bit.
    Even moving the front of the motor a 1/4 inch up or down can make a difference.
     
  13. ghettobiker

    ghettobiker New Member

    i'm no engineer but, i would mount the engine to the seat support frame first,to get proper alignment first,then make front mount out of alum block with longer studs.chain alignment is critical,believe me!
     
Loading...