Ultra quiet 70 CC?

[andyinchville1]

Just wondering, but if a person were to weld a steel pipe to the outlet of the
factory exhaust and route it into a small car muffler would the result be a
motor bike that is as quiet as a car?.....I thought it might be neat to be super stealthy!.....I do recall that there was mention that the intake may also be a source of noise and was thinking the same basic idea could be employed there too....but since the carb is close to the frame anyway it may be necessary to make a custom intake so that an intake silencer can be employed.....Anybody out there try anything along these lines?
Andrew

 

[azbill]

I think it would cause to much back pressure and be detrimental to power
my chopper had a lot more 'git-up-n-go', when I cracked the long exhaust and switched to the stock one
the long pipe was quieter, but the short one made a BIG difference

 

[andyinchville1]

I was thinking that because I would be using a car sized muffler that there would be no significant back pressure since it would originally be designed for a large V8.....I was hoping this would give noise reduction without loss of performance....well, except for maybe the weight factor...
Andrew

 

[davidsis]

Car muffler

sounds like it might work

 

[rcjunkie]

It would be quiet but ugly. No worry w/ backpressure since the car muffler is designed to accept 4+ more flow than a 1 cylinder engine.

 

[Patch]

Well with less backpressure...I believe the muffler would be more like a resonator. Ya know, like a real tingy pop pinging sound from the muffler. But that is a good idea. hows about a dirtbike or and FMF atv muffler those are very muffled even when you drop them on the floor. just watch the backpressure. So i think a large atv FMF silencer would work always wanted one on my gokart but they're pretty pricey!!!

 

[motoschwinn]

Well how quiet is the POO POO pipe? I need to find something too, and there is a go-cart shop, that I was looking at having them make me a quieter exhaust system....

 

[motoschwinn]

Plus I get lots of noise from the clutch side of the motor, when I press my fat old leg up against the cover it cuts out most of the noise... I was thinking of some kind of rubber covering, but it seems to be really hot. Performance for me is not the issue, I just want to run as quiet as possible.

 

[andyinchville1]

I am guessing that the poo poo pipe is muffles like the pipe than comes standard with kits from Dax / Kings etc....I think the pipe just looks different because if the longer tubes...so with that I would assume that there would not be a significant difference in sound level (increase or decrease) ...Others may jump in if they have first hand knowledge of this tho.....The mufflers on lawn mowers... say for in stance the Kohler 25 HP engine....are somewhat larger but still do not muffle very well,....I hate to say it but I think for supreme quiet without unnecessary power robbing back pressure, a good car muffler would be hard to beat....If I weren't so busy I would experiment this weekend but lately work has kept me hoppin!
Andrew

PS - Don't forget I have heard others say that the intake is noisy as well BUT I think most of it is the exhaust myself....There are also some people that believe that noise radiates from the cylinder cooling fins....I have seen some people wedge runner tubing in strategic locations on the cylinder heads to keep the harmonics down...I assume that this was done AFTER the majority ofthe noise was address by taking care of the exhaust and intake noise.

 

[Alaskavan]

So, has anyone come up with a way to make one of those 70cc's quiet? I've been thinking a bit about stealth. Wouldn't it be cool if I could build something where it would take very close inspection to see/hear there was a motor involved. I know this is not practical on a 2 wheeler (I'm thinking beyond the milk crate on the rack mount), and it may be anathema to the serious gear heads, but still.... Whisper quiet is what I'd like.