How can i install a 79cc predator engine with gear kit on frame with built-in tank?

Discussion in '4-Stroke Engines' started by Braapmotorsports, Dec 2, 2015.

  1. Braapmotorsports

    Braapmotorsports New Member

    I have already built a two stroke so I am familiar with motorized bicycles. I want to build a 4 stroke motorized bike with the harbor freight 79cc predator engine. I was wondering if anyone would know how to install a sbp gear jackshaft kit with that bike. I know you need some special 4 stroke gear box that comes on 49cc kits, but I would much rather go for a predator engine. http://www.sickbikeparts.com/catalog/product_info.php?
    Sbp kit
    cPath=21&products_id=110&osCsid=1aiugs9m8goret37j1s5n7deo4
    Frame
    http://www.ebay.com/itm/281824101458?redirect=mobile
     

  2. Prerunning

    Prerunning New Member

    Someone has done this build already and completely documented it with videos, pics and links to the parts. Search it. Op is cruiser***** something
     
  3. Prerunning

    Prerunning New Member

  4. ColdCruiser

    ColdCruiser Member

    I used two jackshafts with gear reduction on both. Just rode it for the first time. It's a blast.

    I chose to use a steel-frame bike because I kept reading about aluminum ones breaking while riding and I really don't want that to happen to me.
     
  5. KCvale

    KCvale Motorized Bicycle Vendor

    There might be enough room in the GT2-150 frame, 4-stroke shifters go quite nice, but why the 79cc Pred?
    Is it a Tool Time 'More Power' thing?

    How fast realistically do you want to go on a bicycle?
    I find 35-40mph as long as it has good brakes to be plenty fast but I'm old and the folly of youth is out of my system, literally beaten and busted out from not seeing the big picture of safety beyond the rush for speed.

    Stay alive to get a real motorcycle some day, they are designed for speed and weight, don't risk your life trying to make a bicycle a motorcycle, especially yourself with just a little 2-stroke build under your belt, you are dealing much more power and weight than that little engine had on a bicycle.
     
  6. Timbone

    Timbone Active Member

    What is the difference of power between a predator 79cc and the stock HT 66cc? Is it a significant power difference?
     
  7. ColdCruiser

    ColdCruiser Member

    The power is probably similar. You can hot-rod either one and get more power than you want. The HT probably has a better power-to-weight since it's a 2-stroke(?). If power and space is your main concern, a 2-stroke will work fine. The predator 79 is supposed to be 3 hp stock.

    I wanted a 4-stroke mainly so I wouldn't have to carry oil with me but also supposedly quieter, less maintenance (last longer?), regular garden motor, lots of performance upgrades available. It is wide. I don't know how fast I could get it to go, yet. That's the first question everyone asks but pulling a trailer with my dog in it, I only want to go 15 - 20 mph. It will easily hit 35 mph @ ~3,500 rpm. If I removed the governor it could probably hit 50-60 mph and that's WAY faster than I would want to go on any bicycle.
     
  8. KCvale

    KCvale Motorized Bicycle Vendor

    Does anyone else find it disappointing when someone posts a question and doesn't even come back to see the answers?
    Two months now, I won't be answering ANY more question from this guy, why bother?
     
  9. ColdCruiser

    ColdCruiser Member

    Years down the road someone might have a similar issue and they will be thankful for an answer.
     
    Timbone likes this.
  10. Timbone

    Timbone Active Member

    I read your replies. :)
     
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