How to pedal with NO added motor xmission loss/drag?

Discussion in 'Motorized Bicycle General Discussion' started by svejkovat, May 25, 2009.

  1. svejkovat

    svejkovat New Member

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    Want to be able to pedal start the engine.
    Want to be able to pedal without turning the engine xmission/jackshafts/pulleys/belts/sprockets, etc.
    Want to integrate the engine into the bike at the crankset in order to take advantage of the
    rear derailleur.

    Tossing this around in my head for days, the only way to accomplish all of these goals is with a
    manually activated PTO clutch between the engine speed reduction (xmission) and the crankset.

    The PERFECT solution would be a freewheel with integrated manual clutch, but I'm having a hard enough time simply finding a small clutch even without it being built around an overrun (freewheel) cog.

    Anyone else faced this and found a solution? I really don't want to fall back on pull starting. Pedal starting would be so much better. If not for the starting dilemma, a centrifugal clutch at the motor and a double freewheel on the crank would be everything that I need.
     
  2. Cabinfever1977

    Cabinfever1977 New Member

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    get a jackshaft kit.
    the engine runs to the peddal sprocket and comes with clutch in peddal sprocket and will run threw your bike gears.
     
  3. svejkovat

    svejkovat New Member

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    Can you give me a link to a jackshaft kit that has a clutch on/in the pedal sprocket? It would have to be a manual clutch.. pedal crank (or jackshaft for that matter) won't provide the rpm for a centrifugal. I have not seen a jackshaft like this.

    If you're referring to the sickbikeparts jackshaft kit, they state specifically that you must use it with a "typical chinese 2 stroke bicycle engine kit". That means a motor with internal gear reduction and internal clutch. There is no clutch included in the sickbikeparts kit. It's in the chinese 2 stroke motor. In fact, since those 2 strokes must be using a centrifugal clutch, then the "clutch" must simply be a method of locking up the clutch long enough for the motor to start. If this is the case, then the rest of the gear reduction and chain to the bicycle's rear wheel is engaged when pedaling even with the motor off. This is exactly what I'm trying to work around.

    I'm trying to do this with a 4 stroke, and would like to pedal start it rather than pull start it. I have not seen a solution to this yet.
     
    #3 svejkovat, May 26, 2009
    Last edited: May 26, 2009
  4. HoughMade

    HoughMade New Member

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    SBP works with a manual clutch....most "typical" Chinese 2 strokes use a manual- not centrifugal clutch (though the centri-clutch is available).

    It is in testing stages for 4 strokes, but those will all have a centri-clutch except the new EZ Motorbike kit. That is the only one I have seen that can be pedal started with a 4 stroke. The problem is, if you have a freewheel in the system to eliminate drag when pedalling, you cannot pedal start it. This would pretty much go for ant 4 stroke out there.
     
    #4 HoughMade, May 26, 2009
    Last edited: May 26, 2009
  5. wheelbender6

    wheelbender6 Active Member

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    My solution is not easy. If I have an engine problem requiring me to pedal a long distance, I plan to simply remove the motor chain, put it in a plastic bag and toss it in my backpack.
     
  6. svejkovat

    svejkovat New Member

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    ALL of the above compromises would be dealt with using a small manual PTO clutch. I've called a dozen clutch manufacturers and sprocket manufacturers and have been met with mostly stunned silence. This animal just does not seem to exist. A small clutch with bell, swage plate, thrust bearing, and cable attachment is certainly not unconcievable. Unfortunately, it's beyond my own machining skills and for some damn reason, totally unheard of.. anywhere on earth!!!! It's built into manual xmission motorcycles by the millions, but unavailable as a separate unit. God this is frustrating.
     
  7. HoughMade

    HoughMade New Member

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    Well, not all would be dealth with. You would still be spinning part of the clutch while pedaling unless you had a freewheel- and thel you could not pedal start.
     
  8. Cabinfever1977

    Cabinfever1977 New Member

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    you cant peddal start a cent clutch engine,you have to pull start it.
    you peddal start a man clutch engine.
    i have a dual start 2-stroke and it can be peddal or pull started and it has a cent and man clutch.
    i can peddal the bike with clutch pulled in and theres very little drag at all.

    remember just like a car,you can push start a car with man clutch but not a automatic(cent) clutch.
     
    #8 Cabinfever1977, May 26, 2009
    Last edited: May 26, 2009
  9. svejkovat

    svejkovat New Member

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    you cant peddal start a cent clutch engine,you have to pull start it.
    So you eliminate the cent clutch..


    you peddal start a man clutch engine.
    Exactly. I just want to put the clutch between the engine xmission and the pedal crank... not between the engine and the engine xmission. Otherwise you're cranking the engine xmission with the pedals when you don't want to be. Perfection would be a clutch built into a sprocket right on the pedal crankset. Then you'd have no more drag than is induced by the pawls on a freewheel.


    i have a dual start 2-stroke and it can be peddal or pull started and it has a cent and man clutch.
    i can peddal the bike with clutch pulled in and theres very little drag at all.

    So do I. Two of 'em in fact. They're 49cc Puch mopeds. Consider what is required to pedal start an engine that has both cent clutch as well as a motor starting clutch (it's not a 'manual clutch' since it's not really intended to engage the engine gradually from a stop in order to get the bike moving, but only to start the motor while rolling). You're spinning the chain and gear reductions all the way up the line right to the motor shaft itself (the only place with sufficient rpm to run a centrifugal clutch) while pedaling with the motor off! The Puch is a real SOB to pedal in this manner. It's better just to get off and push the damn thing. Your 2-stroke kit is less of an SOB to pedal, but still an SOB.

    There was a response in one of the threads here in regard to someone's pedals that went something like "pedals? You're still pedaling?" ..followed by a few knowing smirks and guffaws from other contributors. I really do get the feeling that perhaps the majority of motorbicyclists are of the same mind. I really am not trying to hang a trimmer motor off of a cruiser bike and putter around beachfront drive just for kicks.

    There are wonderful little motors available out there with great power to weight ratios, and there are top-notch lightweight, extremely solid, extremely efficient, mountain bikes out there. These offer the opportunity to, for the first time really, combine the best of both extreme fuel economy motoring, and real bicycling.

    This is an opportunity to really "go anywhere". Distances that would be impractical on a bike for most people. Getting to work without having to take a shower after you arrive. Public trails, parks, boardwalks, and pretty much anywhere else that motors are prohibited are open to you. The motor is shut off and you have a fully capable and efficient mountainbike. I can't do that on my Puch. You can do that only to a very limited extent wth your 2-cycle kit.

    Don't tell me you're going to do much trail pedaling or travel much real distance at all under pedal power with your setup. In fact, as it is, it's too loud and smokey, just like my Puch, to use among any large groups of people without attracting unwanted attention (not the kind of attention I want anyway when minding my own business riding).

    It's really very frustrating that so few seem to be really expanding this horizon. Do you realize that most of the kits you've got ginned up are LESS sophisticated than the state of this art seventy five years ago?
     
    #9 svejkovat, May 28, 2009
    Last edited: May 28, 2009
  10. skjjoe

    skjjoe Member

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