Tips on quieting the muffler?

[mxchris727]

I couldn't find any thread like this so I am starting a new one.

I have recently finished building the 80cc kit and it has been running smoothly. The only problem I have is that the engine is too loud!!! I have tried putting steel wool into the muffler and have also tried putting pipe insulator around it. They both work well for about 5 minutes until they get to hot and burn to a crisp.

Has anyone hushed their muffler successfully yet?

[Humsuckler]

instead of using steel wool, use R20 house insulation! dont pack it too to tight. (insulation doesnt burn up that fast, remember, its a building code thing)

[Nashville Kat]

They were bugging me to post photos on my thread about putting two 16 ounce beer cans around the pipe and extending it.

here's a pic, before I rode tonight and the bottom one came loose because it's only taped and I have to get another radiator clamp for it-

The duct tape was smoking quite a bit so I'm not sure how well that will work out- It probably adds a little quiet, but I'm sure not as much as the cans themselves-

the only question- does it hold too much heat on the pipe?- a great heat shield otherwise and I suppose holes could be drilled in the cans- but then less muffled-

If the duct tape burns off, then you'll have to just have to beer can lables showing- chose your poison!

By the way, I painted both the motor and pipe with auto store touch up paint when I got my kit- (and a clearcoat)

The pipe burned and peeled quickly, but the motor's always been fine- and looks nice in pale metallic blue- I guess it's like the black kits.

how about some annodized paint? That might look good...

[BarelyAWake]

You have a great idea there, one I just might do myself - but your simply using the wrong product lol

Exhaust/manifold wraps are somewhat common on performance racing vehicles under the idea that keeping the exhaust gas temp as high as possible increases velocity and thus performance. A secondary benefit would be to keep the radiated heat levels down - in this case, away from your shins For us, it should work quit well to quiet the noise a bit, I remember it took some of the "bang" out of the noise from my headers on my old truck.

For $10 it cant be beat, remember to look for motorcycle wrap as automotive may be too wide.



It's available in a variety of colors, some variants are self-adhesive (but I would use fasteners anyway)

Also remember the old equation; trapped water+metal=rust, but with the low replacement costs for these exhaust systems - I don't think that's a problem.


Hey - thanks for the idea man, I hadn't thought of this, but I'll prolly skip the can extensions

[mxchris727]

I looked up the motorcycle wrap and it seems good... but there is not much clearance between the pedal crank and the muffler. If I use the wrap, I cant petal. Is there anything I could put into the muffler that wouldn't burn and is not toxic?

[TerrontheSnake]

Stainless steel pot scrubbers... Works effin great and they don't burn at all, but they add resistance and therefore you lose performance. I think your best betwould be to focus on doing an expansion chamber and adding a silencer to the end of that. If you have a welder some plate metal and a hammer they are not that hard to do.

[restapukin]

or maybe it would be profitable to focus on the noise that comes from the inlet side of things - through the carby 'throat'

on my grubee 49cc inlet noise is greater than exhaust noise,
.......say 60% inlet noise vs 40% exhaust noise at a guess....

I'm still thinking about easy ways to reduce inlet noise .... but i want to both quiet down the intake and improve performance (slightly) at the same time.

This should be pretty easy, I'm thinking, ... given the lack of attention to inlet noise implied by the use of a small lightweight plastic filter box.

restapukin
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[mxchris727]

I am more worried about the exhaust because when the engine is revved, you can hear it from blocks away.... It sounds like a chainsaw.

[restapukin]

mmm.... yeah... noise bugs me, too, but all i'm saying is that we tend to think of the engine noise as being mostly exhaust noise

but maybe this is not the case... listen carefully & objectively... listen "outside the square" if yer like...

are you sure that your biggest problem is the exhaust?

no big deal... i'm curious what others think, actually... is all...

restapukin
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[restapukin]

just... the other day i got my head close to the engine & moved it (my head) around whilst listening to the noise output & blipping the throttle

must have been a horrible sight....

but i was thinking how loud the intake was & how quiet the exhaust was ...