Can you recommend a reliable powerful 4 stroke?

Discussion in '4-Stroke Engines' started by swbluto, Jan 24, 2010.

  1. swbluto

    swbluto New Member

    Hello, I'm thinking of a motorized bicycle for long distances such as on the highways and was wondering if anyone could recommend any reliable motors. See, if the thing breaks down when I'm 100 miles away from the closest civilization, I'd be basically screwed.:sweatdrop:

    So, I'm looking for something that would be reliable. Also, I'm looking for something that could carry 350 pounds up a 8% hill at >20 mph. I haven't done the calculations yet but I think that'll require at least 3 kW at the wheel (or about 4 horse power). I plan on putting this on a pusher trailer for gearing and setup advantages, and I'll have a trailer anyways for my stuff.

    I also want something quiet or "not so noticeable" because I basically want to keep it concealed from any inquiring cops, or at least minimize attraction. I plan on having an electric assist for short distances in town or other sensitive parts during the journey, but I need to make sure the cops half a mile ahead can't hear me. (And make sure the engine isn't visible at a glance)

    Any recommendations?

    I'm not that sensitive to price, as long as it has good value (i.e., excellent reliability).

  2. GearNut

    GearNut Active Member

    One brand comes to mind: Honda.
  3. professor

    professor Active Member

    I think GearNut gave real good advise.
    Another guy mentioned he wanted to go to China on a bike pulling 400 pounds of gear and 2 dogs. I didn't say what I thought.
    Why take a huge risk on the mechanical integrity of your machine in some remote place? When you don't have to.
  4. andyszyd

    andyszyd Member

    "So, I'm looking for something that would be reliable. Also, I'm looking for something that could carry 350 pounds up a 8% hill at >20 mph."

    You have to lower your expectations or get a medium size motorcycle to do that.

    No 49cc MB engine has enough power to pull 350 lb up 8% grade at 20 MPH.

    You'd need an engine with 5-6 HP or more + proper gearing, engines of this size are heavy and difficult to mount on a bicycle, also legality issue of a large engine comes into play.
  5. GearNut

    GearNut Active Member

    If legality is of no concern to you, you can run a 5hp Honda thru a Q-Matic transmission and be really happy. It will be a very large powertrain though.
    Sorta like making your own mini motorcycle.
  6. HoughMade

    HoughMade Guest

    If you want it all (again no legality issues) take that Honda 5hp (or 6.5) and slap a Comet CVT on it.
  7. swbluto

    swbluto New Member

    Also, keep in mind, since it's in a trailer, a smaller than usual wheel can be used. I'm thinking something like 10".

    The advantage of that is that the required transmission gearing ratio would decrease: compared to a 26" wheel, it'd decrease by more than half. I think this might simplify the gearing requirements and might make a single speed possible with a "broad powerband" engine.

    How do you guys think this would compare to using the motor to power a generator that'd recharge the batteries to power the electric motor? More costly? More efficient? I pretty much have no welding or part fabrication ability, but I'm pretty good with electronics.
  8. MikeJ

    MikeJ Member


    Look for something else to carry that much weight at those speeds and that grade of hill. If you have to go down that hill at any speed above a crawl, that trailer plus 350 pounds plus you plus that bicycle need way more braking power than what any bicycle designed for a 200 pound passenger can provide. If you had to emergency stop and locked both bicycle wheels, that trailer will run right over you after you fall down sideways and skid on the pavement.

    I speak from experience from a long time ago. I lost a load of hay because that little farm tractor I was driving had no braking power on the hill and the wagon had no brakes. I was lucky I did not get killed. And there was no traffic around me.

    Bicycles are not made to do as you dream. Motorcycles are not made to do as you dream. Get a cheap pickup truck and learn how to maintain it. Motorize your bicycle and enjoy it without a trailer. Do not connect any bicycle to a heavy trailer! That is simply asking to be injured for life. If you disregard my opinion, I hope the police do stop you for lack of regard for your own safety.

  9. MikeJ

    MikeJ Member

    Let's talk legality -

    I don't know of any state that allows engines of 50 cc or greater to be utilized on public roads unless that 2-wheel motorized vehicle is registered and licensed as a motorcycle, the rider is endorsed as a motorcycle rider after having obtained motorcycle insurance (if you can even obtain it), and the vehicle (bicycle) has a headlight, tail light, turn signals, and a horn.

    To take a bicycle with an obvious over-sized engine to push it along out on the public road is just plain dumb and an invitation to a lot of legal trouble. Now, I will cut swbluto some slack because he is a newbie and probably has no inkling what his state laws are. He has a lot to learn. Welcome to this forum!

    Be assured that in every state in which unlicensed vehicles (with very specific exceptions) are on public roads, the law enforcement officer is required to remove the vehicle from the road. That means impoundment with daily storage fees and a court date and fines. If you are two states away from home when this happens, you are just plain out of luck.

    Now let's talk accident... If you are cause of an accident and are injured while riding an unregistered bicycle with an engine that requires vehicle registration as a motorcycle, don't expect any insurance company to come to your aid. They were not paid to accept risk for your dumb actions, and they have no obligation to pay out. If you are hurt, you pay your own ambulance and hospital bills.

    SWbluto - Learn the laws of states and laws of physics. I encourage you dump your original idea (as good as you think that it is) and get a small maintainable pickup truck if you have to carry that much stuff around. Stay legal. And get insurance.

  10. Happy Valley

    Happy Valley Active Member

    I'll use the bandwidth to quote this in entirety because it's such excellent advice.
  11. andyszyd

    andyszyd Member

    Well, that's sums it up folks, dreams are dreams, but it is always better to be worry than to be sorry.
  12. swbluto

    swbluto New Member

    Ok, here's the deal. This is not that much different from taking a bicycle across the road and yes, I'll be researching the laws in advance with this one. The reasoning being is that the electric is stealth (And electrics are allowed anyways where I would go), and the whole idea was to hide it. If it really seems that hiding the gas engine is impractical, then I'll reconsider this option. Note, my other option is bringing a genset along to charge the batteries so there's not some necessary need to mechanically power it using gasoline, which sounds like the type that might be hard to conceal.

    Now onto the practical advice - the bike will have regenerative braking to recharge the batteries during a descent, so downhill speed isn't a worry. And, if it is, it's pretty easy to increase the drag to slow down the speed.

    The trailer itself will probably weigh around 20-25 pounds and the generator may way upwards of 65, and include 20 pounds for stuff, so we're talking about 100-110 pounds on the back. Considering that tandem braking technology is designed for upwards of 2 full sized adults (a.k.a, 500+ lbs), I think 350 pounds is well within design limitations.

    Note, the electric part of the bike could easily sustain 60 mph if I so designed it. The thing is that the batteries couldn't take it for more than 4 miles, so it'd only be a "short distance" only option.
    Last edited: Jan 25, 2010
  13. andyszyd

    andyszyd Member

    Good luck with your dreams man, electric hybrid MB is a pipe dream, too much weight, money, and technology overload for a dubious benefis and performance.

    If anybody proves me wrong I'll be happy to jump in.

  14. Happy Valley

    Happy Valley Active Member

    Not necessarily.


    A rack mounted MB drive could be used that would add maybe 15 lbs.
  15. swbluto

    swbluto New Member

    Let's take this one step at a time.

    1) Too much weight. It's true that I'm thinking about adding an extra 60-70 pounds over what I would usually carry, but with it being in a trailer and ONLY used for long distance trips (greater than 30 miles), that's not exactly a show-stopper.

    2) Too much money. Well, I already have an electric bike with the batteries, so the electric part are "sunk costs", and I'm only forward looking. For the 90% of my trips, I rely on electric and don't pay a thing for gas. For the rare long distance, $400-500 is just a small drop in the bucket. It gets even less than that if I'm willing to be satisified by lower uphill speeds. (Hey, 1200 output watts or about 1.5 hp gets me 20 mph, and I think that should be within the realm of gasoline+electric+pedaling. 100 human input watts, 300 electric watts(to conserve battery power), and 800 gasoline watts or about 1 gasoline horsepower. I think that's obtainable with 50cc.)

    3) technology overload. lol. I suppose for some. Another way to look at it if it's in "parallel" is increased system redundancy. a.k.a, increased reliability.

    Note that the above is not "proof" as it's obviously highly situationally dependent (i.e., I already have an electric bike and you most likely don't, so the cost analysis will be different from your POV).
  16. andyszyd

    andyszyd Member

    If electric or hybrid gas/electric would be the answer nobody would bother with gas bikes or cars anymore.

    Hybrid cars are still not mainstream and they may never be.

    Hybrid MB with batteries weight and cost + generator/ gas engine weight and cost + elecric motor weight and cost + control system weight and cost crammed on 30 or 40 lb bike is a total nonsence and a wishful dream.

    Prove that electric hybrid MB will outperform a gas bike of similar weight being competitive in and price + potential fuel savings.

    If your hybrid MB can outperform gas bike then prove that a total cost of it would be amortized in let's say 2 years or so, offsetting initial cost by a fuel savings.

    I,ve been searching for MB set-up allowing to ride very rough and steep mountain road single tracks, another word I want to follow Gary Fisher without much of peddling LOL.

    The only solution seems to be a top quality Mountain Bike with dependable motor (no problem, Honda GX 35 or GX50, Titan, or Subaru ECO or Mitsu 40 or Tanaka will do) + Staton box married to NuVinci tranny, expensive and heavy set-up.

    For the price of this I can have 200cc Lifan dirt/road legal 16HP 80MPG bike which will carry me on the top of the highest mountain only limited by MINE technical capability, AND on the way to get to those mountains I can travel up to 60MPH on the asphalt. And yes with its 5 speed manual tranny I can go up to 30% ascents even haul a trailer if I want to.

    That's what I will most likely go for, since no MB can even come close to this performance including initial price.
  17. professor

    professor Active Member

    Andy nailed it quite well.
    If you did the gas/electric with a standard generator, you will need to convert the 110 output to the voltage of your bike, this means a transformer. Ever pick up on of those- very heavy.
    I am doing a gas/e-bike (on the electric section) to get away from the limitations of batterys.
    NOT for efficiency, but because only e-bikes are legal here.
    I am using a 24v alternator and HF79 to drive it.
    The motor is a scooter 24 v 450. The bike will run off the batterys and the gas engine is the on/board genset.
    If a small, light DC generator was available, that would be the cat's meow. A lot of people are not real happy with batterys.
  18. swbluto

    swbluto New Member

    You know, I'd appreciate if people actually tried to help with the original intent of the thread instead of distracting from it with unconstructive criticisms.

    Anyways, to andy, it's clear we have a different set of values.

    You talk about "total cost". The only thing that matters is "future costs" as past costs are sunk, and future costs are entirely situational..

    Then you talk about performance. I care about performance, true, but I'm not trying to maximize the performance/price envelope.

    For this, I care more about reliability. A parallel hybrid system would have supreme reliability compared to relying on one system or another. If the gas engine goes out, I should still have about 60 miles on an electric charge at a slower pace of 15-20 mph, assuming I contribute an average of 100-150 watts. I can fix whatever needs to be fixed at the next destination, and charge on route if need be. It would lengthen trip time in that emergency scenario, true, but I wouldn't be "stranded".

    As to criticisms of the hybrid design, I think you're likely just hostile to electric systems in general. That's OK, if you don't see any advantages with them. However, I find substantial advantages with being able to go *wherever* I want, when I want, without noise disturbances nor dirty looks nor the thought of polluting the air that detriments the health of those around me. In urban areas, I try to avoid health-harming emissions as much as possible (or minimize my contribution), and electrics have a supreme advantage in this department. By using a hybrid system, I would be able to take advantage of the best features of electric while retaining the range advantages of gasoline. Furthermore, I can *take* away the gasoline part just by undocking the trailer so that I won't have its disadvantages in sensitive areas, nor the weight.

    Also, this also has a large educational benefit, as towards my future phev that I'll likely custom make.
    Last edited: Jan 25, 2010
  19. fm2200

    fm2200 Member

    This talk of getting more from a mere bicycle with a gas/electric combo is attainable. But the limitations are not realized by the guy that's trying to achieve this on the least possible $$ spent on said venture. Real safety is not going to be achieved with thoughts only of propulsion, to further complicate matters a trailer is in the mix. My view is this is only suppose to be a simple means of getting around for less $ for gas and have a little lighthearted fun in your travels. Try to take stock of the life and limb at stake-yours and maybe someone else.
  20. swbluto

    swbluto New Member

    "Cheaper way of getting around for less money". No, not really. Flight would be a cheaper option considering the probable lifetime of the gas engine, maintenance costs, the extra time taken when going bicycling speeds, and the amount of long distance trips I plan on taking. And there are even cheaper options than flight.

    It's more to do with the adventure of touring by bicycle, with the added advantage of a substantially increased practical range in a given day. I can get to Norther California in about 12 days by manually biking, or 3 days with an engine. The time advantage has a lot to do with it over a regular bike, and the adventurousness, "peacefulness" when I want it, and the versatility over a regular motorcycle.

    I suppose I could get a regulator motorcycle and just bring my electric bike/scooter in a trailer. :thinking: That may make more sense economically and time-wise, although 60-70+ mph on two wheels just doesn't seem safe to me. (But how much safer is it then hugging the shoulder of a 60 mph highway on a bike going 30-35? I dunno.)

    I also found the carb compliant honda 50cc motor that puts out about 2 hp. That might have good legality in the event of being stopped, and might mate well with a recumbent (Aerodynamics, comfort and all).
    Last edited: Jan 26, 2010