2 stroke vs 4 stroke

Discussion in 'General Questions' started by thrustrc, Jul 24, 2011.

  1. thrustrc

    thrustrc New Member

    Could you guys tell me some andvantges/ disadvantages. Cost, size, noise and such. From what i can tell haPpy time kits arn't too reliable. But a 4 stroke will be around 300. Please share your experiences

  2. motorpsycho

    motorpsycho Active Member

    a 2 stroke will rev a lot higher than a 4 stroke. a 2 stroke will make more power in the upper rpms than a 4 stroke, plus a 2 stroke can be tuned to hit the power band with an expansion chamber. an expansion chamber (when tuned right) will act like a supercharger. parts for a 2 stroke are generally cheaper than they are for a 4 stroke.

    4 strokes do not rev as high but they make a ton of low end torque. you can buy speed parts for 4 strokes and you can get a ton of power out of a 4 stroke but it'll cost you a ton of money (research jr. dragsters & parts for the engines)
    a 4 stroke is just like a car engine with an intake valve, exhaust valve, a cam, and tappets(lifters).
    a 2 stroke has no actual valves unless it has reed valves (h.t. engines don't), no cam, no tappets, less internally moving parts.
    a 2 stroke will generally be louder than a 4 stroke, but a 4 stroke can be VERY loud with the right pipe on it.
    4 strokes are generally bigger than 2 strokes of the same c.c.'s.
    you can do a ton of work to both a 2 stroke and a 4 stroke, but you will get a better quality 4 stroke for a bicycle. on the other hand, the 2 stroke bike engine kits are cheap and they are throw away engines basically.
    you can buy them cheap, ride them until the puke and then buy another one for under $100.00.
    you can sink $300.00 easy into a 4 stroke, and then when it pukes you can spend another $300.00 fixing it (or replacing it).

    a 4 stroke has oil in the crank case that will need to be changed on occasion. a 2 stroke has no oil in the crank case...the oil to lube the brearings and rings comes from the 2 stroke oil that you put in the gas.

    I guess a lot of it is personal opinion for the application.
    In my opinion, the cheap h.t. 2 stroke is the way to go when building a bicycle.
    Mostly for amount of power they make for the low cost. They also look a lot better in the frame of a bicycle than a 4 stoke does.
    Have you ever ridden a 2 stroke dirt bike or a 4 stroke dirt bike?
    a 2 stroke will usually walk away from a 4 stroke due to the higher rpms. and the power that they make in those high rpms.
    but these days, 4 stroke dirt bikes are just as fast as the older 2 strokes used to be, but there has been years of research and development behind making a 4 stroke dirt bike perform as well as a 2 stroke.
  3. Chalo

    Chalo Member

    Two-cycle engines stink, smoke, make horrible noises, wear out quickly, and have really poor low-rpm performance. That's when they're working as designed.

    Four-cycle engines can have all the same problems, but only when they're broken.

  4. thrustrc

    thrustrc New Member

    Thanks for the info... I have A 2 stroke 50cc scooter, it had some good powr but it was a bit louder than id like. What vendors have you had good experience with? Any trouble with cops?
  5. Happy Valley

    Happy Valley Active Member

    If you look right at the bottom of this page you'll see a number of suggested threads that match your subject line. Those and many others are in the archives here, there is a lot of opinion available and some of it even makes sense, lol. jk

    Not all 2 strokes are alike and all are certainly not like the HT engines. I have both 2 and 4 strokes and that includes some Mitsubishi 2 stroke engines. They are not noisy nor smoky nor smelly, have good power across the rpm range, are EPA and CARB II certified and employ advanced 2 barrel intakes and stratified scavenging in cylinder porting. Tanaka engines also come to mind, I do not own any but have friends here that swear by them.
  6. Chalo

    Chalo Member

    I understand that those engines cost at least as much as similarly sized four-stroke engines, and they do still burn lubricating oil in the fuel by design.

    Given that two-stroke engines are by nature cheaper, lighter, and smaller than four-stroke engines of similar power, you'd think that they'd be common in cars and motorcycles. But they are too polluting to comply with emissions limits for roadgoing vehicles.

    It would be a good thing for a reputable major manufacturer like Honda to bring a comparatively clean direct-injection two-stroke engine to market in a size that would work for MBs. Orbital of Australia makes some small direct-injection two-strokes that are used on Vespa scooters and a few other niche models.

  7. dougsr.874

    dougsr.874 Active Member

    A 4 stroke is superior in every way....But, if you pay $300. for a 4 stroke kit you are screwing youself,(frame mount kit)...the engine is not the problem, its the gear box....be sure to stay away from the Hoot gearboxes
  8. darwin

    darwin Well-Known Member

    A 35cc R/S will run about 250$ shipped same as a honda 35cc and theres nothing wrong with a 2 stroke mits or tanaka except they're a lil louder. 1 thing about a tanaka though is theyre expensive just below a morini in cost.
  9. Happy Valley

    Happy Valley Active Member

    Yup, good engines, have several which I like very much but just to put it in prospective for the original poster, in the same 35cc engine class the Mitsubishi TLE33 goes for $165 right now at Viza.

    The exhaust note of the 2 strokes is of course a higher pitch but it's uncanny, when I've used a hand held dB meter on both a Robin EHO35 and a Mits TLE33 with the bikes on a set of rollers, the difference is within 3 to 4 dB. I've found adding a foot of common black heater hose to the exhaust nipple knocks down much of that 2 stroke ping.

    I have a friend with a Yamaha Zuma 50 scooter and it's hard to believe how quiet they have gotten those, plus when we ride together, he'll leave me in the dust with that 50cc CVT, lol.
    Last edited: Jul 25, 2011
  10. Chalo

    Chalo Member

    +3 dB is about twice as much sound energy. It doesn't make that much difference when you're right up on it, but it projects to a larger area. There is also a less important quality-of-sound issue. At the same volume, a chainsaw is much more irritating than a lawnmower (though neither is exactly charming).

  11. Happy Valley

    Happy Valley Active Member

    At a certain point, if the sensitivity to the inherent characteristics of ICEs are a cause of disdain and condescension, one might wonder what motivates the interest in motoredbikes in any form?
  12. loquin

    loquin Active Member

    The higher pitch (with more harmonics) from two strokes can be irritating to a lot of people. And, even though you may like it, the neighbors might not. I would think that it is a valid point to be aware of.
  13. bilboby

    bilboby Member

    Having now tried out both 2 & 4 Stroke engines along with my very limited mechanical knowledge i personally prefer 4 Stroke. I'm currently (& very pleased ) using a honda gxh 50 for friction drive and apart from the few tantrums the honda was giving at the beginning. I can honestly say that after perhaps now around 150km of engine break in it's performing like a dream with almost no problem what so ever mechanical wise other than tyre wear and also other day when i mistakenly filled the tank up with diesel and not gas. I didn't realize until i left the garage for the open road when i noticed Parisian car drivers trying to attract my attention as fumes were bellowing out from the exhaust whilst riding happily along without a care in the World. Luckily the Police weren't around otherwise they'd of thrown the book at me in term's of a fine. I emptied the tank along with the oil chamber with a good clean cloth before replacing with proper fuel etc. Hence to date the 4 Stroke honda never suffered any serious damage however had it been a Chinese 2 Stroke what would serious damage if any would of been done?

    Happy MB Riding over the Weekend
    Last edited: Jul 28, 2011