Very quiet 2-strokes?

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JohnnyCrash

New Member
Jun 28, 2012
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Earth
Howzitgoin' eh!

I've decided to forgo the Ryobi 30cc 4-stroke conversion... Far too many extra bits to hunt down, spend a small fortune on, remachine and adapt.

The Skyhawk 66cc 2-stroke kit is available, supposedly powerful, and cheap--and mind-blowingly noisy.

Has anyone had any luck getting these (or any other 2-stroke) to run quietly? What sort of exhaust system (commercial or homebrew) are you using? I understand piston-port induction 2-strokes produce a lot of intake noise as well, any luck reducing the 'chainsaw on wheels effect' in the intake department?

Thanks,

Ian
 
pocdragon

pocdragon

New Member
Apr 30, 2011
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an oversized muffler from a 13HP briggs will flow well and quiet the exhaust. you can even piggy back 2 or three of them into eachother to maximize quietness

there is alot of intake noise aswell, so maybe a large airfilter and longer intake tube would benefit you decible level.

Also: chain noise is the kicker haha
 
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cmanns

New Member
Jul 1, 2012
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Santa Cruz, California
The 33/36cc? I picked up today had the standard K&N looking filter yall use. I'd find some sort of duct that's wider, make a base around the carb side and duct that. Should quiet it down quite a bit if you duct it down and maybe wrap it with some insulated tape :) Remember, for the intake. I'll probably be doing similar as my motor will be on the back with the exhaust near my back exhausting towards the rear, and the intake is sort of below/near the wheel, so I want to get it more fresh air flow.

Exhausts.... I've never done 2 stroke exhausts. From browsing here a week or so my goal is a tuned expansion chamber, will prob try long and short however not sure how long I'll use the 33cc. After the expansion chamber I want to see if welding some non resonating pipes over and building a sort of free-flowing chamber muffler over the banana would quiet it.

Sort of like pocdragons large 13hp briggs muffler being put to the end of a expansion pipe.

Good luck & post what you do man :)
 
Mike B

Mike B

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Mar 23, 2011
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I added a small Briggs muffler and some plumbing.



Reduced the exhaust noise enough that I was able to hear the intake noise.
 
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xenodius

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May 23, 2012
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Spokane, WA
This isn't the answer you're looking for, especially considering the extra cost and (often) significantly lower range... but I have been quite impressed by ebikes, and if you want a quiet ride, they may be a good choice. As many have said in the ebike forum, shoot for a LiFePO4 battery. =) There are some drawbacks, including cost, but zero noise is definitely a huge plus.

And hey, littletinman, I'm curious-- where did you get your replacement muffler? =) Sounds like an upgrade I'm game for...
 
Pilotgeek

Pilotgeek

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Apr 6, 2011
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Green Bay, WI
Honestly, my stock muffler is quite quiet. I added some cork gasket to the inside of my clutch cover, and put on a better air filter. The clutch gears make a lot of the noise, and greasing and muffling those helps a bit. Dampeners between the cooling fins help a little bit with noise, but not enough that I cared to keep them. I'm really surprised when I buzz past someone walking in a parking lot and they don't even seem to look over or notice me.
 
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JohnnyCrash

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Jun 28, 2012
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xenodius said:
This isn't the answer you're looking for, especially considering the extra cost and (often) significantly lower range... but I have been quite impressed by ebikes
Click to expand...

I built an ebike with 50 pounds (!) of lead acid batteries, an Audi 5000 cooling fan motor, and a homebrew MOSFET motor controller. Went like a bat outta ****, about 65 km/h--but the battery pack was getting 'soggy' after 10 minutes at that speed :) The silence was golden, though--especially around the cops :)

Longer high speed run times is what I want. The newest lithium polymer batteries are light and compact, but I'm just not up for dropping $1200+ for a battery pack to put in a $150 bike, that's all hehehe

I scored a pair of Grubee 66cc wingdingers, one rebuildable and one for spares. I'll probably experiment with extended tailpipes and intake tracts--a foot of heater hose on the weedwacker performs small miracles in the noise department.

Peace

Ian
 
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nightcruiser

New Member
Mar 25, 2011
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A lot of guys run modified exhaust systems that are quite loud. I still have the stock exhaust and I don't find it to be very loud at all, those little cars with the funky mufflers are much louder.
Previous posters have given you good advice, but I would say you should build up the stock kit first and see how loud it is and then decide if you need to modify the exhaust...
 
DP454

DP454

New Member
Jul 18, 2012
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Florida
I going to experiment with noise canceling tech. I research a couple of web pages and can fabricate one of similar size to the stock. I'll let you know in about 2 weeks when I return from the states and bolt it on. I had to remove all the "stuff" from my stock exhaust. It plugged up! Now it cracks like a dirt bike but runs like the wind. The noise canceling technology uses chambers to reflect the sound back at itself...canceling it out. We will see. BUT, the chain and gear noise is still quite loud. Is this normal?
 
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goofyfoot2001

New Member
Aug 16, 2012
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South Carolina
Mine is stock and it is only loud when WOT. At cruise speeds its not loud at all. I've also noticed that you get in tune with the bikes throttle up and down hills and you yourself tend to keep the bike quiet. I was afraid of the noise but no longer.
 
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nightcruiser

New Member
Mar 25, 2011
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goofyfoot2001 said:
Mine is stock and it is only loud when WOT. At cruise speeds its not loud at all. I've also noticed that you get in tune with the bikes throttle up and down hills and you yourself tend to keep the bike quiet. I was afraid of the noise but no longer.
Click to expand...
My stock exhaust is pretty damn quiet too. Like you said, if you mind the throttle you can keep her quiet. Right now my motor runs so smooth that out on the road you can barely hear it idle, when I pass by police I lighten up on the throttle so as not to flaunt it in front of them and she gets pretty damn quiet when I back off the throttle a bit. Even at WOT it's not too loud. As long as you don't gut the muffler or have any exhaust leaks I think the sound level is pretty reasonable...
 
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