push trailer 4 stroke question

Discussion in 'Push Trailers' started by TheOtherStyle, May 22, 2009.

  1. TheOtherStyle

    TheOtherStyle New Member

    so in the interest of doing things as cheap as possible, i'm looking at canabalizing the lawn mower my mum just replaced. only problem is that its a vertical shaft, not a horizontal.

    is there a way i can make a vertical shaft work? can i mount it vertical to make a faux horizontal shaft, or should i try to get the transaxle from a rider mower, or ?

    or...should i just continue to save up and get the 80cc kit from bikeberry to start out with, and just say screw it to a pusher for now?

  2. s_beaudry

    s_beaudry Member


    Ahhhh... the world of vertical shaft engines, brand new 5hp engines for $90, or abandoned ones are a dime a dozen.

    The bad news.... pretty much worthless in the world of MB'ing and push trailering. There would have to be so much modifications to the engine that it would far outweigh the cost of saving for a new or used horizontal shaft engine. Heak, you can go to Harbour Freight and get a brand new 2.5hp horizontal shaft engine (with 20% off coupon) for a very meager $80!

    Turning a vertical shaft engine sideways would cause the crabuerator not to work, it would cause a serious oil issue in the engine as well (lack of oil moving around).

    Using a lawnmowers gears as in a self propelled mower will net you no return, it is no where near strong enough or geared to move more then 2mph maybe.

    Learning from all my mistakes, save your money and get the brand new 2.5hp from HB and build off of that....

    When you are ready to build, please post here as we are a very crafty bunch in the pusher forum! We can and will help you!

  3. Rgvkid

    Rgvkid Member

    For the amount of time and effort to make it horizontal, your better off selling it and putting the money to a $130 6.5 from Harbor Freight or $80 for the 2,5hp. Check out the DIYgokart forum. They have some builds using the vertical shaft but its alot of work.
  4. TheOtherStyle

    TheOtherStyle New Member

    for the time being then i suppose i'll just get the 120 dollar 80cc kit from bikeberry and attach it to my road bike. have something to ride while i make something for my fs mountain bike.

    thanks for the answers!
    Last edited: May 22, 2009
  5. Rgvkid

    Rgvkid Member

    The HF clone motors will probably last longer then the 80cc you want to get. Just my 2cents.
  6. Tinker1980

    Tinker1980 Guest

    It's not such a big deal to make a lawnmower engine run on it's side. At least not with the 3-3.5 horse B&S engines, which you will find most often at the curb on trash day. The carburetor is slip-fitted on a tube that runs to the intake valve on the other side, this would be the most difficult part to modify. Only because you'd need to make a bracket to hold the carb and gas tank a different way, and maybe make the intake tube longer. Next would be to open the case, and fabricate a splasher that would reach into the oil, that attaches to the connecting rod bolts. A bit of sheet metal would work for this. Last but not least, you'd have to decide how you wanted to put oil in the engine. You could leave the oil fill the same, and simply lay the bike on it's side to fill it, or thread a right angle pipe with a cap into the hole. The oil cap isn't vented, so you don't have to figure out a vent. This might cost $20 in materials, IF that.

    Or, if you happen to find one... what about an angle grinder gearbox? Find a burned out angle grinder and use the gearbox on it?

  7. RMWdave

    RMWdave Member

    or you could probley get some 90 degree gears.....
  8. EsQueue

    EsQueue Member

    That wouldn't last a block. The gears are usually the second most common failure on those grinders. That bike would also be noisy as **** as those gears make more noise than the grinder's motor.

    EDIT: the censored word begins with h not f. -_-
  9. Just_Gasit

    Just_Gasit Member

    If one was desperate to use a vertical shaft motor, you could try a "V" belt drive and let the belt handle the 90 degree twist. Heck, Corvair's did it for the cooling fan.
  10. shecky

    shecky New Member

    I've seen some gardening equipment (edger, I think) that did that 90 degree twist with a v belt. Don't know how well it works.
  11. EsQueue

    EsQueue Member

    Good idea but a cooling fan and edger puts low stress on that belt. If used to drive I can only guess that it would suffer from insane wear. I haven't seen it though.
  12. loquin

    loquin Active Member

    Roto-tillers often have a 90 degree gearbox, and are geared so that they could be usable. (Apx. 250 RPM range for engines running at 3500-4000 RPM. If you remove the engine governor, the gearbox output shaft might be spinning at the right RPM for a 1:1 to 2:1 chain drive hookup to a 26 inch bike tire.
  13. Tinker1980

    Tinker1980 Guest

    Heyyyy.... There's a mantis tiller for sale down the street...

  14. cooltoy

    cooltoy Member

  15. loquin

    loquin Active Member

    Not a good design... It might work for a while, but, think about it.

    1. You're applying the friction drive pressure to the sidewall, where the rubber is thinnest...
    2. Assume the drive roller is a half-inch 'thick', top-to-bottom. The top of the roller is at about 12.5 inches from the axle, whereas the bottom of the roller is at about 12 inches from the axle. This means that at a given ground speed, the portion of the tire in contact with the top of the roller wants to move at a radial speed (in RPM) that is about 5% slower than the part of the tire in contact with the bottom of the roller. (it's farther away from the axle - the radius is larger) Since one part of the tire wants to move at a faster rpm than another, you're going to get excess friction wear and heat, which will tend to wear through the thin sidewalls even faster.
    3. The IDLE roller, intended to keep the tire in place, will ALSO be causeing the same sort of tire sidewall heat and friction...
    Having sidewall breakdowns is NOT in your best interest.
  16. EsQueue

    EsQueue Member

    Wow, it's the simple things that people never look at that are the most dangerous. I would never have thought about the different speeds from the portion of the tire that is near the rim to the side near the thread.

    Good points.