Quiet Motor

Discussion in 'General Questions' started by Scatcat1994, Mar 21, 2014.

  1. Scatcat1994

    Scatcat1994 New Member

    Hi guys. I'm just wondering if anyone can help me with this, I'm looking for a Motor which is quiet. Would anyone be able to tell me the overall quietest engine for a bicycle. 4 stroke, 2 stroke and also if there is a difference in sound levels between say a 50cc, 66 cc and 80cc. Thanks for your time,


  2. battery

    battery Member

    if you are looking for a stock motor that is quiet then 4 stroke with a good muffler. the differance in level of sound between the 50 and 66cc are slim. if you go with a 2 stroke get a muffler with good baffling the intake will be louder than the exauhst.
  3. grinningremlin

    grinningremlin Active Member

    You didn't state, but I gather you are talking frame-mounts by your engine choice.If you want the all around quietest most reliable, easiest to start, you want a Robin Subaru EH035, which are usually rack mounted.
  4. FurryOnTheInside

    FurryOnTheInside Active Member

    And be aware you can only legally ride with an engine mechanically connected to the vehicle when off public roads i.e. on private land, areas where 'crossers are allowed. Good luck with it and hope you enjoy whatever engine you choose. :)

    Aye and don't forget to introduce yourself in the introduce yourself section. ;)
  5. butre

    butre Well-Known Member

    If you want quiet, go 4 stroke with huge displacement and a good muffler. There's not a whole lot of noise difference between 50cc and 500cc at a given RPM but the bigger displacement means more power at that given RPM, so you're not likely to need higher RPMs as much.
  6. Fabian

    Fabian Well-Known Member

    4-strokes tend to be quieter.

    2-strokes can be made to be just as quiet, but it takes a little more effort.

    Adding two and a half feet of chemical resistant, high temperature 1/2 inch internal diameter silicone hose makes a world of difference to exhaust noise reduction:

  7. jaguar

    jaguar Well-Known Member

    that's true
    the expansion of the hose diameter as the exhaust pulse passes thru it means some of the pulse energy is being wasted into the hose, resulting in less pulse energy at the final exit of the tube. that means less noise.
    better yet is directing the hose backwards instead of downwards so that you breathe less fumes at a stop light.
  8. Fabian

    Fabian Well-Known Member

    I don't spend much time at stop lights. Just the word stop lights is giving me an (Inspector Dreyfus) blood pressure spike.

    Last edited by a moderator: Dec 15, 2015
  9. FurryOnTheInside

    FurryOnTheInside Active Member

    Of course the OP never said whether he's intending to run the engine on public highways in Scotland at all. Supposing that he does want to ride on the road "under the radar" though, I think having the pipe pointing downwards would be more stealthy. Supposing that he only rides off road, I think having the pipe pointing backwards would be more healthy for him and the delicate highland wildflowers lol.

    On a side note.. How long does it take a chrome exhaust pipe to turn that nice stealthy grey?
  10. Fabian

    Fabian Well-Known Member

    If you mean the muffler section of the exhaust pipe, then the answer is simple. Take a Scotch-Brite sponge pad and laden it with some Ajax scrubbing powder, then rub the muffler section.
    This action will give a brushed aluminium finish.

    Personally i prefer the chrome finish, but (at the time) i wanted to quickly clean the muffler from baked on 2-stroke carbon sludge, mixed in with road grime and Warburton Trail sand and cement dust residue.

  11. FurryOnTheInside

    FurryOnTheInside Active Member

    Thanks. Yes that was what I meant, the curved tube and the wider muffler section. I think that finish looks great on your bike, matches the colour very nicely and is a lot less obvious than a matt black pipe. :)
  12. Fabian

    Fabian Well-Known Member

    That's really a two part question that requires two answers. The first question has been covered above, in description of the wider muffler section, with the brushed aluminium finish.

    The colouration of the curved tube is simply chrome plating that has exceeded it's heat tolerance and discoloured to a burnt bluish-brown & nickel finish.
    That particular muffler has been on my bike for around 30,000 kilometers (18,600 miles) and it's gathered a lot of history on it's surface.
  13. FurryOnTheInside

    FurryOnTheInside Active Member

    Crikey, 18,600 miles! I'll have to see what I can do with a blow torch.. (and the abrasive scrubbing)
  14. Fabian

    Fabian Well-Known Member

    I say that to myself all the time, and i am quite surprised that the aluminium frame hasn't developed fatigue cracks.

    I gave it no more than 10,000 kilometers (6,200 miles) before i'd have to replace the frame, because it uses relatively thin wall aluminium, but the frame continues to hold up with 55,000 kilometers of use (34,150 miles in 4 years) over some rough country with the occasional crash thrown in for good measure; two crashes being fairly spectacular.

    What is more impressive is that the bike was just an AU$500 base model 27 speed (now a 16 speed) with standard specification wheels. The standard (Quando) front wheel is still on the bike and the rear wheel has been replaced 5,000 kilometers ago because the hardening (where the wheel bearings are located) failed inside the hub, requiring that a new hub be installed.
    I happened to get a reasonable deal on a complete replacement Shimano rear wheel, but that wheel uses (black) spokes that seem to break every time you run over an ant, and they keep breaking at the spoke flange; never anywhere else - most frustrating.

    The original Quando rear wheel "NEVER" broke a spoke (and i could never understand why people were breaking spokes) so i'm now chasing a replacement original Quando wheel, because Shimano spokes are complete garbage, or better put, not worth a pinch of the proverbial.