2 stroke muffler question



fastboy9

Member
Joined
Jan 22, 2008
Messages
585
Should I have?

Hi just got a brand new exhaust pipe its just the stock one you get with the chinese 70cc kits. I removed the baffle completely by cutting the thin tube off and then smoothed all the rough edges off of the insides, so it is basically the open can with the cap on the end and the little tube sticking out the end. Would this damage the engine and would it increase the performance? thanks Ryan:D
 

cooltoy

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Joined
Jan 6, 2008
Messages
341
I don't know if it will increase the performance but the noise level sure will increase to the point that "stealth riding" will never be possible.That's just me but getting pulled over wouldn't be cool.
 
Joined
Jan 10, 2008
Messages
61
Hi Fast,

I've removed the baffle on my 70cc engine as you have described and the performance increase is very noticable. I've actually drilled several additional holes in the bottom cap to lower the back opressure, which also helped with performance. My bike is quite a bit louder now, but since I often ride in traffic, the additional sound is a bit of a safety factor (keeps driver's aware of my presence).
 
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fetor56

Guest
Hi just got a brand new exhaust pipe its just the stock one you get with the chinese 70cc kits. I removed the baffle completely by cutting the thin tube off and then smoothed all the rough edges off of the insides, so it is basically the open can with the cap on the end and the little tube sticking out the end. Would this damage the engine and would it increase the performance? thanks Ryan:D
It won't damage the engine and you'll see a noticeable performance increase...all this comes at a cost though(it'll be louder)
 

Skyliner70cc

Active Member
Joined
Nov 17, 2007
Messages
1,347
Engine damage can occur anytime you decrease engine back pressure without changing the mixture setting. Anyone who knows anything about engines/motorcycles knows that a free flowing exhaust requires a richer setting unless the engine was running rich to begin with.
 
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fetor56

Guest
Engine damage can occur anytime you decrease engine back pressure without changing the mixture setting. Anyone who knows anything about engines/motorcycles knows that a free flowing exhaust requires a richer setting unless the engine was running rich to begin with.
Go tell Dax that...he's an engineer and he recommends it on his website(without modifications)
 
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thatsdax

Guest
Not to worry..

IF you believe that drilling or cutting your inner tube will lean you out, you only need to do plug chops and then make your adjustments. I have not noticed any leaning out on my engines. I notice a power increase for sure. It also gets somewhat louder. But not much louder. Maybe 1 db louder. Make sure you leave an inch or so of the inner tube. Do not cut it too close to the end. Some back pressure is good and also aids in engine power. Thanks.. Enjoy the ride..
 

Skyliner70cc

Active Member
Joined
Nov 17, 2007
Messages
1,347
Go tell Dax that...he's an engineer and he recommends it on his website(without modifications)

Degreed engineer? The reason he doesn't recommend any modifications is because he is at 5250+ altitude and the happy times run pretty darn rich at that altitude. I should know, I'm at 7600 feet ASL.
 
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