Ultra quiet 70 CC?

[andyinchville1]

I agree with alaskavan....it would be really neat to be stealthy on a cruiser type bike and blow by some really hard core bicyclists (the ones that look like they belong in the Tour De France)....Like Mr. Bean or Pee Wee passing all those decked out racers...that would be too funny!....I am actually going to try the car muffler
idea when my work slows down and I get some free time
Andrew

 

[joelvanderhoof]

Has anyone tried putting fiberglass muffler packing into the muffler to quiet it down? I know that's what they do for 2 stroke dirt bikes.

 

[gauge]

i was thinking the ame thing at school today while the teacher was boring me mr vanderhoof , if i pack the muffler withh fiberclass packing it may quieter her down to be alittle more steathy to sneak up on people

 

[andyinchville1]

I think packing our mufflers with fiberglass would cause undue back pressure....the "cherry Bomb" glass packs for automotive use is a straight through design with louvers and then the area outside the straight through pipe is packed with fiberglass...If you try it, definitely post your findings...

Andrew

 

[Alaskavan]

I don't recall the cherry bombs being particularly quiet. At least not on my hotrod.

 

[Dockspa1]

2 strokes require a little back pressure to run right. I remember when I was young playing with the dinosaurs, I had an old sears 250 with the baffles. I thought it would scream if I took them out. Man was I wrong. It had absolutely no power band. Low or High. They went back in pronto.
Here is a good question that maybe someone here knows the answer too.
Are the pipes that go on the 48cc the same as the ones that go on the 70cc.
They probably are due to the cheapie Happy Time traditions.
One is either too big or too small for the proper balance.
Maybe just a 1/4 " hole drilled in the 70cc would help to balance it?
Any thoughts or facts?
Doc

 

[joelvanderhoof]

I picked up some 2 stroke silencer packing at the local shop. It was easy to put in. I just undid the screws at the end of the exhaust pipe and pulled out the pipe. Mine was drilled full of holes and pinched in the middle by the people that I bought the kit from. I went ahead and wrapped it with the packing, put it back in, and took the bike for a test run. The response on the throttle was a bit sluggish. The HP was still there though it just took a little longer to pick up. The noise reduction was HUGE though, and I mean HUGE. It was really freakin' quiet. The squeal that the clutch gears make is the loudest sound that my bike makes now.

I'm gonna try taking a blowtorch and monkey wrench to the pipe and take the pinch out of the middle and see how that affects the sound and torque. I'll try and post some pics too.

 

[Alaskavan]

Yes. Pics and more detail please.

 

[joelvanderhoof]

So I just took the bike for another test run and I have to say that the torque just isn't there when I'm going up hills. I think that the reason for this is that my pipe was pinched at the center by the person who sold me the kit. Here are a few pics. I haven't been able to heat the pipe and force it back to a circle in the center with a blowtorch and pliers. What I'm thinking is that I should drill a hole or two in through the pinch to open it up.

 

[joelvanderhoof]

Here's another couple of pics. I'm thinking about wrapping only part of the pipe. That way there is still some room for compression.