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Silencer Experiment

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Thanks again to Ed for sending me a silencer to work with. :thumbsup:

I studied different designs from different companies to try to come up with a decent prototype. I used mostly ideas from Flowmaster, but not copied exactly. Corsa actually has the best designs for the size, but there is way too much cost in time and materials to try and reproduce one for my KX.

Here's where I'm at so far on the first design. I picked up some 22 ga. sheet and had some leftover 1/2" electrical conduit for some "chamber ports" I guess you would call them. I'm trying to keep at least the same amount of volume throughout the design to reduce a bottleneck/back pressure situation.

The 1" strips will be the frame of the insides of the muffler. The plan is not to alter the aluminum housing, exhaust tip and front pipe.

100_1778.jpg

100_1779.jpg

100_1780.jpg

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Here's the final construction pics. It was a tad difficult navigating the recess for the rear brake caliper. Turned out pretty decent, let's see how it performs.

Silencer003.jpg

Silencer004.jpg

Silencer005.jpg

Silencer006.jpg

Silencer007.jpg

Silencer009.jpg

Silencer010.jpg

Silencer011.jpg

Silencer012.jpg

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After installing the modified silencer I had to adjust the air screw and idle slightly. There is a mellower note coming from the silencer. However, there's so much noise coming from the pipe that it's hard to differenciate from the video. The aluminum tape is just temporary. I need to get some header wrap and a sound meter.

Stock

th_Silencer014.jpg

Silencer015.jpg

Modified

th_Silencer016.jpg

th_Silencer018.jpg

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I am curious what may happen to the aluminum can now that it is no longer protected from the exhaust heat by any packing.

After you wrap the pipe, you migh consider covering the wrap with a pipe guard to make it look a little better. That would probably help to protect the wrap and keep it from getting torn up while riding too. Just a thought...

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That looks like a good design! Iv'e been trying to design a better silencer for my xr650r. It has a White bros now with a quit core.It works ok but nothing like a Stock dr-z 400 silencer (Good power with NO noise, Although heavy..)

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I am curious what may happen to the aluminum can now that it is no longer protected from the exhaust heat by any packing.

After you wrap the pipe, you migh consider covering the wrap with a pipe guard to make it look a little better. That would probably help to protect the wrap and keep it from getting torn up while riding too. Just a thought...

Good idea, Man! :thumbsup:

I think the inside of the can is just going to get gummed up and crap. I'm not going to keep it installed for any long period of time until I measure engine temps and backpressure.

After the pipe is wrapped I should be able to capture the sound it makes.

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That looks like a good design! Iv'e been trying to design a better silencer for my xr650r. It has a White bros now with a quit core.It works ok but nothing like a Stock dr-z 400 silencer (Good power with NO noise, Although heavy..)

I think I may have lost some weight on the silencer. The packing is a little old, but with the mods installed it's pretty light.

The good thing about this is I can change the design without ruining a complete silencer.

The sound that was emitting from it was definately muffled and had a different tone. But the Pro Circuit pipe on it is loud as F...k!

I'm open to more ideas. I'm going to try to order the header wrap this week and figure out how I can measure back pressure accurately.

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How does it compare performance wise? I wonder if incrased back presure would cause head temps to go up?

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How does it compare performance wise? I wonder if incrased back presure would cause head temps to go up?

I don't know yet.

Looks like I just need to plumb a low pressure guage on the exhaust to measure pressure.

Once I get the decibles farther down, I'm going to bring the bike to a local bike shop that has a dyno. Then I can compare results with stock parts. I might even run the PC pipe seperately to see if I'm gettinf any gains from it.

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A carbon fibre pipe guard will significantly dampen the ringing noise from the pipe. I recently installed a Enduro Engineering pipe on my KX, pretty rare, they only made it one year, and I havent been able to find a cf guard for it. Ive been running it w/o one and man is it loud!

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Sorry for asking but what exactly are you trying to accomplish by building your own silencer? Better power, less noise, a combination of both?

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Is it just my eyes or is your rear fender, number plates, and seat moving in a wavelike fashion

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Is it just my eyes or is your rear fender, number plates, and seat moving in a wavelike fashion

My bikes have some serious Mojo.:thumbsup:

j/k camera frame rate v. vibration.

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Here's where I'm at now, and kinda stumped a little.

I installed the header wrap on most of the pipe. I came up a little short and should have ordered the 1" instead of the 2" because of the design of the pipe.

Pipe006.jpg

I also installed the gauge to try to measure back pressure.

Pipe007.jpg

I started it up and it was noticably quieter, but not as quiet sa I would like. As far as performance, I had to bump the idle up a hair to idle smoothly. At this point, I could rev the engine and the gauge would read 2-3 psi for a split second as it went up in RPM's. At idle with the modified silencer or without it read zero.

So I ripped down the parking area where I work :thumbsup: and it seems to have the same snappy power it had before. Obviously not a dyno result yet, but I'm working on it.

Anyway, now the gauge doesn't read squat. :p And I don't know where I can get a low pressure air gauge that might work. Also, I think some fiberglass packing in the silencer might quiet it down some more.

I'm open to suggestions.

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I would think that with the wrap on the pipe you would increase the heat in the exhaust and force more heat flow out the tail pipe and cause a rich condition.

as far as the silencer goes the sound waves could very well vibrate that thin apart.

just keep in mind you are changing known engineering.

I like FMF Q stealth.

I think you need to get out and ride, this tikeridiss is getting out of control ! perhaps we need a TT ride intervention to help save you from accidentally creating some kind of new propulsion source from sound harmonics. LOL!!!

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I would think that with the wrap on the pipe you would increase the heat in the exhaust and force more heat flow out the tail pipe and cause a rich condition.

as far as the silencer goes the sound waves could very well vibrate that thin apart.

just keep in mind you are changing known engineering.

I like FMF Q stealth.

I think you need to get out and ride, this tikeridiss is getting out of control ! perhaps we need a TT ride intervention to help save you from accidentally creating some kind of new propulsion source from sound harmonics. LOL!!!

ROTF :cry:

I ride too! But on the weekends. LOL ...I race even.

I just don't like having a rocket launcher look-alike for a silencer. :thumbsup:

Plus, my ORV park is closing down in September and I need a more "stealth-like" ride. :p

(check my new sig.-lol

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