Quiet Motor

[Scatcat1994]

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,

Scott

 

[battery]

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.

 

[grinningremlin]

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.

 

[FurryOnTheInside]

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.

 

[butre]

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.

 

[Fabian]

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:

 

[Deleted member 12676]

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.

 

[Fabian]

better yet is directing the hose backwards instead of downwards so that you breathe less fumes at a stop light.

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

 

[FurryOnTheInside]

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?

 

[Fabian]

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

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.

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