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Good day.
What is there that i can do to get the exaust and overall noise of the bike down. I need the bike to be as silent as posible.
Let met explain why. I live in South Africa on a game farm. I want to use the bike to patrol my fenceline and drive between my game. I dont want to scare the animals.
Any advise will be much appreciated..


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There used to be a device called a db Snorkel that was like an extra muffler after the muffler. Making something like this, or lengthening the stock muffler can help. I think Kolpin makes one nowadays, they're common on some ATV's. The valves will be the noisiest part, keeping them in adjustment will help for that, as well as being one of the few things you gotta do to have a good engine life. You'd probably want to do some carb adjustment and maybe a slight jetting change.
 

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Remove the spark arrestor and wrap it with as much muffler fiberglass as will fit, slice masking tape to about 1/4 inch wide and tape fiberglass in three places to hold it while you re-insert the spark arrestor. Use a screwdriver to tuck in loose ends and free up the hole for the bolt as you push it back on. I found that this will cut noise by about 30%. I also found that the increased back pressure made it run rich. At 5,000 feet the factory 126 jet was perfect until I did this....now I have a 122 jet for 5,000. Yes, I did lose a little power, but it's only noticeable flat out in 5th gear. Since the TW runs pretty lean at sea level, I would think it might be just right after wrapping. You can tell it's too rich if it starts bogging in 5th up hills.

There is nothing that can be done about the valve train rattle except to ride at low RPMs. I've snuck up on deer to 50 yards after this mod.
 

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I have a second muffler welded onto one of my TWs, it helps a little with sound attenuation.
My other TW achieves similar noise reduction with a simple 45 degree copper elbow redirecting sound pulses leaving muffler towards the ground.
On some very small displacement nitromethane glow plug engines thin wall silicone tubing is used to muffle the exhaust note after leaving tuned expansion chambers. Flexible tubing seems to absorb sound pulses well, at least on 20,000+ rpm screamers. If you can find tubing with less than 1/8" wall thickness it may be flexible enough to really help.
Valve train and driveling noise will then be the biggest offenders.
Keep the rpms down is the easiest and most effective noise reduction strategy.
 

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The 45 degree copper elbows can be found in hardware & building supply stores.
I wonder if a 90 degree fitting would silence it a bit more? Or be too restrictive?

A change to a FMF Powercore muffler solved my exhaust noise problem!

My name is Dave and I am a smart-ass...:grin:
 

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I agree with the copper 45 fitting. The sound is directed downward more and it's quieter this way. Also, a TTR225 or 250 header pipe from stainless steel is a LOT quieter than the stock header pipe. A heavy aftermarket skid plate also reduced mechanical noise.
Using a light hand on the throttle, short shifting, lugging the motor all aid in keeping the noise down. I jetted for lugging power and this thing can motor from idle up to mid RPM's and pull very strongly. Past that, the motor and the whole bike buzzes and makes tons of mechanical noise not directly from the motor exhaust. I may try to play around with burn resistant insulation to see if there's more that can be done to quiet the bike further.
Oh! Forgot to add;
I took a chunk of bicycle innertube and stretched it over the exhaust. Maybe 3 or 4 inches long. Then I slit it in two so it was like a duck bill flap. The rubber really helped and the back pulse sucks in the rubber flaps and really helped to kill the echo sound of the muffler. I've seen these sorts of rubber extensions with two flaps on the drain from air boxes on various motorcycles. The flaps keep water from getting into the air box on deep water crossings. I just moved the premise to the exhaust pipe outlet.

Looks like this but stretched over a 45 degree copper pipe fitting and slipped onto the tail pipe of the muffler so it points down at an angle to the ground.


Here's another style that might work. I have not tried it though. Found this one on eBay;
 

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I can attest the Db Snorkel worked great on several 2 strokes I had. They are not made any more, but there are youtube videos out there to show what they looked like and it seems it wouldn't be too hard to build one out of scrap parts.
 
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