Things what don't work: silicone 90-deg coupler to reduce exhaust noise

[kawasaki999]

My tubing has been on since day 1, I have 2 exhaust outlets, hit 13,200 rpms, 50+ mph. Tuned to the max rpm then richen 200 rpms. I am sure if I ran on the lean side they would melt.

 

[happycheapskate]

I found this thread by a search on Google.

I'm using the stock Tanaka 3300 muffler, and have thought about the Daves silicon tubing to re-direct gasses, and maybe cut the noise a little. Sounds like it will just melt though. Oh well. At least the can muffler shoots the exhaust to the side of the bike ("back" of motor if clutch is the front). I think I'll just leave it alone.

If you had used the search engine, you would have found a lot on failed and functional exhaust devices that would have save some time etc.

 

[Richard H.]

The problem with the 2 stroke weedwacker engines is they are designed for hand held landscaping equipment and their certificates are designated for off-road use. Excessive noise abatement is not much of a consideration in their development and hearing protection is recommended for their 100 to 115 dBs noise signature for any protracted use of more than a few minutes. For on-road noise abatement I've found studying scooter exhaust design to be the pertinent context but of course there is the trade off of added bulk and weight of heavier gauge steel components necessary for really effective sound deadening.

 

[happycheapskate]

For mine, the worst noise came from the intake. It seems to have helped that I made my own intake after loosing the cover plate.

http://motorbicycling.com/picture.php?albumid=531&pictureid=3846[/IMG

The exhaust is still noisy, but not as harsh as many commercial trimmers I've used and things like chainsaws. The engine seems to wind up to less than 10,000 rpm anyway, so it is not really a screamer.

I think it would be cool if someone made a baffler for this, in the style of a singular, narrow, thick pipe, with the twisted flat stock shoved inside to "swirl" the gasses and make a more constant exit flow.

 

[nightrider]

I see mention of JB Weld in threads like this. Has anyone tried something called Thermosteel? It's sort of a high temperature epoxy mixture made by a company named CarGo for exhaust repairs and is available at Advance Auto Parts, Autozone and presumably other auto supply stores. The specs claim it will withstand a maximum temp of 2400F.

 

[Fabian]

Is there a high temp silicon tubing that will hold up? Still looking for a 2-stroke silencer that won't rob too much power.

There most certainly is. Just do a Google search for: "Twin Spark Plug Cylinder Head for 80cc Happy Time Engine"

and scroll down to the third last photo to see the high temperature (chemical resistant) silicone tubing installed on my bike.
The silicone tubing absorbs noise terrifically well and makes the exhaust (under load) virtually noiseless.