How Loud is a 49cc?

Discussion in 'General Questions' started by Electric Rider, Nov 13, 2010.

  1. Electric Rider

    Electric Rider New Member

    I chose an electric bike for quietness and stealth. But after having some battery trouble, I decided, I want a 49cc so I wouldn't be stuck without transportation. How much louder would this engine be if I modified it to go 40mph?

    What's the best cheapest 49cc kit that is easy to mount?

  2. RedBaronX

    RedBaronX Member

    I've got a 66cc, and I'd say the noise level is comparable to a commercial scooter. It's not so loud that it's bothersome under normal circumstances (revving it over and over at 3 am would NOT be "normal circumstances") but it's by no means a stealthy machine.

    As for ease of mounting-- if I'm not mistaken, all of the "Happy Time" engines, no matter who sells them here in the States, are nearly identical in general external dimensions-- at least when you are comparing 49ccs to other 49ccs and 66's to other 66's. Pick a reputable dealer first and foremost. That way if you have problems because you got a lemon engine or one with some defective components, you've got some customer support to help you out.
  3. They aren't to loud. Doubt you could get 40MPH out of a 49cc engine easily.
  4. wheelbender6

    wheelbender6 Well-Known Member

    A stock 49cc is about half as loud as a weed eater.
  5. Electric Rider

    Electric Rider New Member

    What price range should I expect for a good but not overly expensive 49cc kit?

    I have read that alot of people can easily modify a stock engine for an increase in speed. How easy is this really and could I realistically expect to get 35mph?

    I'm going with 49cc because that is the legal limit for where I live before you have to register it and have a drivers license.
  6. Happy Valley

    Happy Valley Active Member

    IMO, if you've become accustomed to the quiet of an electric you might find the HT engines loud, as are many of the weedwacker 2 strokes, just a thought rather than it being a deal breaker later

    Meant as a heads up not as criticism, but in light of your comment about stealth and quietness it might be a good idea to see if you can find someone with a similar ICE on a bike or even check some youtube vids for sound.
  7. RedBaronX

    RedBaronX Member

    under $200-- depends on shipping costs and exactly where you get it

    you're not doing much modifying to the engine itself-- power gains are more form expansion and muffler kits, better carburetor... there is a high performance replacement head offered by Pirate Cycles, but that's only for the 66cc engine.

    I think a lot of people will tell you that you could probably get away with a 66cc without being noticed-- the external size is very close to the same between the two.

    In my state, the limits are placed on the top speed, not so much the engine size-- as long as it's not capable of more than 30 mph, it's legal as a motor-assisted bike. Before you worry too much about making a 49cc bike go 35 mph, you might want to check that out in your local laws. Over 30 might not be legal anyway.
  8. motorpsycho

    motorpsycho Active Member

    First of all, sprocket size,wheel size and tire size make a big difference in how fast these 2 strokes will go...49 or 66 c.c.s
    also, rider weight and bike weight also play a big roll in the speed.
    my friend and i have similar bikes (both are old 20" schwinn stingray frames)
    we are both running 20" wheels and the exact same tires front and rear.
    I have a 49 c.c. engine, and he has a 66 c.c. engine, and both bikes have 44 tooth rear sprockets.
    our bikes went exactly the same speed (about 25 mph) when we first put them together.
    (with me making the test runs on both bikes because i weigh the least)

    I dropped to a 41 tooth rear sprocket, added an expansion chamber, high flow air filter, ngk spark plug, accell 8 mm. spark plug wire and now my 49 c.c. will blow his 66 c.c. away big time. (i weigh 150 pounds, he weighs about 190 pounds)

    we had our bikes clocked with radar, and my 49 c.c. is getting 32 mph top speeds on flat ground with me riding it, and his 66 c.c. is just barely hitting 25mph top speeds with him riding it. his is all stock including the muffler and air filter, but he weighs more than me.

    we swapped bikes, and with him on mine, the top speed dropped to 27 mph, and with me on his bike, the speed increased to 27 mph. so rider weight plays a big roll.

    my occ chopper, which has a 66 c.c. engine, no expansion chamber(it has a long pipe with a modified muffler) a 41 tooth rear sprocket, and a velocity stack on the carb, will hit about 35 mph top speed with me on it.
    the difference is the rear tire size (height).
    my other bike has a 20" wheel with a 21 inch tall tire on the back. my occ bike has a 20" x4" rear wheel, but the tire is 24" tall. the tire height adds a little to the top speed.

    there are several variables that are involved when talking about top speeds, low end power, etc.
    but from what i have experienced, a 49 c.c. and a 66 c.c. will be go about the same speed stock because they are both limited by the gearing.
    your top speed will depend on all the variable (rider weight, rear sprocket size, wheel & tire size, etc.)

    also, if you buy one, make sure to read which engine mount it has. some are listed as "big mount" and these are specifically for bikes that have a bigger diameter front frame down tube than normal. the "big mount" is only the front mount on these engfines, the rear mount is standard size. but if you have a bike frame where the front down tube is the same size as the seat post tube, do not get the "big mount" engine because the front mount will be too big, and it will not fit your downtube. 1/2 of the big mount is cast into the front crankcase so it isn't like you can just change the mount to a smaller one.

    as for noise, they are pretty quiet with the stock muffler. In my opinion (everyone's definition of loud is differnt),both 49 c.c. and 66 c.c. are slightly quieter than a weedeater.
    Last edited: Nov 13, 2010
  9. Electric Rider

    Electric Rider New Member

    Thanks for all of your replies.

    I came across this 58cc. And I think it is a really good deal and I may go with it.

    It's capable of doing 35. Has a range of about 75 miles with its half-gallon tank and it's suppose to be easy to mount to most bikes. I don't have the bike yet to mount it to. But I can buy a bike to match the mounting configuration. I know nothing about this company. But the price is within my budget. What do you guys think?

    Are there any special techniques to quiet the motor perhaps a special muffler or an insulated motor cover.
  10. Porkchop

    Porkchop Member

    Have you ever ridden a bicycle at 30 mph ? If not, you're in for a surprise. Most bikes feel very unstable and dangerous at that speed. I have a Schwinn Suburban hybrid bike with a BMP friction kit and 50cc 2 stroke. It cosistantly goes 27mph on flat ground. I've had it in the low 30's going down hill, and it gets very, very sueirrelie at those speeds. It will make you think how good it's going to feel after the pain goes away after hitting the ground at that speed.....if you live to talk about it !
  11. RedBaronX

    RedBaronX Member

    just so you know, MOST of these engines make those exact claims. "Capable of 35" doesn't mean "35 mph out of the box"; same for the mpgs. Expect more like "not quite 30 mph, and around the low 100 mpgs" with both not happening consistently until the engine has broken in after about a 100 miles or so.
  12. Pablo

    Pablo Motored Bikes Sponsor

    To get those kind of speeds, you will need an expansion chamber. I know for sure you can muffle down a chamber pretty decently.
  13. Virginian

    Virginian Member

    I think that depends on the bike. I have motorized a good-quality front-suspension mountain bike that goes 32 mph on the flat and can go up to 40 mph down big hills. It feels quite stable at those speeds. It also takes bumps in the road quite well.

    I feel quite comfortable riding at 30 to 35 mph, but anything faster starts to make me nervous.

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    Last edited: Nov 14, 2010
  14. motorpsycho

    motorpsycho Active Member

    wow, both of my bikes will do 30 mph plus, and they are both very stable at those speeds.
    on top of that , both of my bikes are little 20 inchers.
    one is a chopper with a raked frame and extended forks, and even is is very stable at 30-35 mph.
  15. I learned if you get a expansion chamber, and some other little engine mods you wil NEED a airfilter. I just drilled a bunch of holes in the from of the plastic peice on mine, it seemed to work. Also another good free mod is mild porting,a nd piston notch.

    Also if you get a 68cc buy a 36 tooth sprocket.

    For $320 on the drivetrain I've got 42MPH out of my bike.

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