100cc Boxer Twin Cylinder Engine - it only needs is a jackshaft

Discussion in 'General Questions' started by Fabian, Apr 10, 2010.

  1. Fabian

    Fabian Well-Known Member

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    Last edited: Apr 10, 2010

  2. SimpleSimon

    SimpleSimon Active Member

    Fabian, for a guy who claims to be concerned with police harassment and excessive regulation of motorized bicycles, you certainly seem to enjoy advocating flaunting the existing laws and inviting yet more disastrous regulation upon others.

    Almost every legal jurisdiction regulates gas-assisted bicycles to an engine displacement of 50 cc or less, and a top speed typically around 20 mph. Not too mention, your typical bike frame is not built for the stresses that large an engine can impose, and frankly, speeds in excess of 30 mph really aren't terribly smart on a bicycle.

    What use is it?
  3. Fabian

    Fabian Well-Known Member


    Your reply to my post requires a simple explanation, that's grounded in physics and backed up by pictorial evidence , though only a load of pine, but i've carried a good 65 kilos (145 lbs) behind the bike.
    A 48cc engine is inadequate, a 66cc engine is inadequate and a 100cc engine would only just be reasonable power with a fully loaded trailer.

    I'm on the record for stating that i don't want excessive horsepower or speed (30 miles an hour is more than enough), but have compelling reasons for requiring a high torque engine.

    Considering i live in an area surrounded by steep hills and considering i'm always hauling weight (lots of it) my needs for a large capacity engine with loads of low rpm torque, using an exhaust system of low noise are completely justified.

    When someone makes this kind of engine available, i'll buy it to bridge the gap to my requirements.
    Anyway, the boxer design is an inherently smooth running engine - something we all desperately need in the motored bicycle world, but until then i'll take anything that improves on the clunky, rattly, filthy, grimy, goo seeping engine that we are all living with.


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    Last edited: Apr 10, 2010
  4. Gh0stRider

    Gh0stRider New Member

    You sure you're not a marketing guy? First it was fuel injected 120cc billet crankcase inducted engines for Rich, and now boxer twin engines with "Engine Monitoring Unit" for Pablo? (also known as EMU, but not to be confused with PIG, which is a Programmable Injection Gizmo) :jester:

    Yes, we know that you're on the edge of your seat waving your credit card. :grin5:

    Did you lose your license or is there some other reason why you don't just buy a small motorcycle. I'm sure that a boxer twin R series BMW could tow a trailer with a couple hundred pounds of wood.

    And if you can't drive a MC, then there are other alternatives to those generic clamp on engines. I've been considering a rack mounted four stroke myself. If you want to keep a ringadinnnggggggg 2 stroke, some kits will work with the Mitsubishi or Tanaka 2 smokes.
  5. give me vtec

    give me vtec Active Member

    if you need torque... build one of these.


    it shouldn't be any more illegal than a bike possessing that motor you posted, and its a lot simpler to build/maintain. It has more torque and power than you will ever need to pull that trailer and it will be a TON more reliable in the end.
  6. pedalless

    pedalless Member

    Fabian there is a electric bicyle i saw on the endless sphere forum towing a school bus
    it had a crystallite rear hub motor also has a range of 200km this might be an option. This member is doctorbass he used old batteries from power packs like used for drills and stuff he also sell these cheaply on this Endless Sphere forum. Might be worth thinking about this way i ordered an electric setup myself as its very stealthy and the petrol bikes are illegal in Australia.
  7. Tanaka40

    Tanaka40 Member

    That trailer is made with plywood. It must weight at least 30kg dry and even more loaded. Try shedding some kilos of the trailer with fiberglass composits over foam . It would be lighter and stronger than the current plywood.
    I would also consider a "booster engine" for when you carry heavier loads like the rack mount Gh0stRider mentioned. That way you can still remain legal and only use the extra power when you need it. Good luck and keep watching for the local law enforcement.
  8. wheelbender6

    wheelbender6 Well-Known Member

    I'd like to find a 50cc version of that boxer motor and build a BMW replica.
    I'd put my Schnauzer in the side car. A motorized bike for the fadderland.
  9. SimpleSimon

    SimpleSimon Active Member


    Your Schnauzer would freakin' love it! My last dog was a mini-schnauzer named Mallory. That dog was affectionately known as "the tractor" - my wife would take her for "walks" by getting on her bike holding Mallory's lead (she wore a chest harness lead outdoors) and let the dog tow her around the neighborhood. Mallory would get a wild hair and start to run, Julie would be yelling at her too slow down and hitting the brakes on the bike.

    Me? I'd be falling down laughing.
  10. Fabian

    Fabian Well-Known Member

    vtec, your engine option is a logical one.
    Unfortunately, in my state, (and the way things work on the ground) it's a non option.
    A friend of mine is a police officer and we were talking about motorised engine kits for bicycles.
    His view as an officer on the ground: if it looks like a motorbike, i'll treat it like a motorbike - no if's or but's.

    Having poo poo pipes or noisy exhaust systems or physically large 4-stroke engine kits attracts way too much attention, worse still are rack mounted engines.
    That's the beauty about the 2-stroke engine kits - they are physically small.
    There is a guy who bought a 4-stroke engine kit from the same retailer i've bought my 2-stroke kit and he has nothing but trouble with the police, because of it's physical engine size - he gets told that the engine looks to big to be legal.
    I guess that's the reason why this particular retailer can't move 4-stroke kits from the shop floor.

    and to Gh0st,

    I will happily buy a 120cc single cylinder 2-stroke (that will work with a shift kit) if it's made available before someone makes a shift kit conversion for the 100cc boxer engine.

    Reality dictates that neither the 120cc engine or the 100cc boxer engine will be made available for motorised bicycle engine kits.
    In saying, i'll just have to put up with an under powered 66cc 2-stroke engine.

    Last edited: Apr 11, 2010
  11. Fabian

    Fabian Well-Known Member

    Hi Tanaka40

    You are very close to the mark.
    I've weighed the trailer and it come in at 25 kilos (unloaded) and i've carried two 20 litre Jerry Cans which would weigh around 40 kilos + the tool kit which weighs 10 kilos and the spare tyre.

    I've realised i'm carrying more weight than i've assumed - 75 kilos (165 lbs).
    No wonder the bike was working it's guts out (4 M/ph or 7 K/ph) in low range crawler gear up some of the hills i've got to travel.
    One of the hills (more like a mountain climb) is a 25 minute ride in low range crawler 1st gear - that's a long time to be doing 4 miles an hour with the engine revving it's guts out with little or no airflow over the cooling fins.

    Last edited: Apr 11, 2010
  12. Gh0stRider

    Gh0stRider New Member

    Well, you don't have to put up with a generic clamp on engine if you don't want to. You need to muster up some Cuban ingenuity and make yourself a bike that is quiet and reliable. I don't rely on my bike as daily transportation so the generic Chinese engine has been good for me. Around 500 miles so far and it starts with the pop of the clutch every time. Just needed a little TLC on installation and some carb tuning to get it perfect. My longest round trip was 40 miles. Got a little scared wondering what I would do if I got a flat tire.

    I don't see how a frame mounted 4 stroke would be much different than a two stroke clamp on engine as far as law enforcement is concerned since anything with an engine is pretty much illegal where you live.

    Rack mounts can be hidden with luggage too.

    Professor made a gas-electric hybrid to satisfy his e-bike laws!

    Yes we can!
    Last edited: Apr 11, 2010
  13. tacoshell4

    tacoshell4 Member

    bike engines go in bikes twin cyl model aircraft engines go in model aircraft lol
  14. Fabian

    Fabian Well-Known Member

    Gh0st, i'm glad you run up a few miles on your motored bike knocking up 40 miles in a trip.

    My travels take me a bit further and the longest single return trip i've done in a day was 90 miles.
    My general weekly trip distance works out to be around 180 miles and so far i've travelled a total of 3300 miles (5500 kilometers), although i'm on my 4th engine (and the 4th engine has been rebuilt with a new crankshaft, so maybe you could call it 5 engines) and worn my way through numerous drive chains and a cassette and rear derailleur. The only original item from the motored conversion is the SickBikeparts Shift Kit (although it's on a second set of chainwheels and Jackshaft output sprocket which is to be expected for the distance travelled and the loads that are towed).

    You can probably see why i carry 10 kilos (22 lbs) of tools in the trailer + spare parts and common consumables like tyres, tubes and drive chains.
    If the bike suffers a technicial failure, 40 miles from home, there is only one option - rebuild the bike on the side of the road.
    Surprisingly the whole mechanical system (SickBikeParts Shift Kit, 2-stroke engine and original bicycle drivetrain) have proven themselves to be far more reliable than they should be on first appearance.
    Typically the 9 speed bicycle chain (Shimano) and (SRAM) last between 600 and 900 miles depending on my attention to lubrication and they don't fail mechanically, but wear past the 0.5% stretch limit.
    I've had a badly bent and twisted Shimano chain last 600 miles before snapping in half at the outer link, though it would be expected after being twisted back into shape; suffering serious metal fatigue.

    Last edited: Apr 11, 2010
  15. give me vtec

    give me vtec Active Member

    have you tried the gebe kit... a tanaka with #11 gear should realistically solve all of your problems.

    -you dont use the bottom bracket, derailleur, or chain.... because of the ring that snaps on your spokes. so wear/maintenance is at a minimum

    -you can pedal to add auxiliary power when needed.

    -the #11 gear and tanaka engine should offer all the torque you need to pull your load.

    -the tanaka engine and Kevlar belt drive should be plenty durable for thousands of miles.

    -you can hide it with racks and luggage.

    -displacement isnt too far from the ht engine and it should be much more emission compliant.
    Last edited: Apr 11, 2010
  16. 5-7HEAVEN

    5-7HEAVEN Guest

    Actually, these Happy Time China engines were originally made for...tillers!

    Hawaii Ed told me so!:detective:
  17. give me vtec

    give me vtec Active Member

    I have a hard time believing that. Is there a bicycle shaped tiller out there I don't know about??? The clamps are awfully convenient if not made for a bicycle...
  18. Fabian

    Fabian Well-Known Member

    Ahh, of course vtec, a Tanaka with an #11 tooth gear.

    Great idea, but what happens when i'm going down hill and want to change through the next 8 gears?

  19. Gh0stRider

    Gh0stRider New Member

    My understanding is that it is a copy of a 50's Russian design. It was meant to be a bicycle engine.
  20. give me vtec

    give me vtec Active Member

    why are you flying down hills in 8th gear with a full 165 lb load behind you???

    Are you just stupid... or did I miss something???