Mod. Stock Exhaust


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heavychevy69

New Member
Marthy said:
Most that likely you will loose top end power and if you are way too lean the throttle transition won't be smooth. It's one of those things... you need to do it all or not at all. If you just mod the stock exhaust a bit, it's fine.

The Marthy Danmoto with DBKiller has enough restriction to run safe too.
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im still a little unclear, forgive me. so will this stock mod with a 2'' pipe cause me to run too lean and lose power?
 
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heavychevy69

New Member
also would i be able to drill holes in this fashion to add a little sound to the exhaust? i dont want to poke the holes in the back of the pipe like some did because i want to be able to do the complete "stock exhaust mod" eventually. but in the mean time is there a problem with something like this? i dont want to have any problems with power loss or running lean i just want a little more grumble on acceleration

 
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poidabike

New Member
After the disappointing resonance I was getting from the 2.5" tip mod, I put an exhaust baffle inside the 2.5" tip with a 1.5" centre hole. The result is much better. Retains the deeper note and most of the annoying resonance is gone. Still some annoying grumble-popping during over-run but not awful - some would probably like it. Next mod is to add a lining of fibreglass exhaust mat inside the tip, protruding into the aft chamber to absorb the remainder of the resonance.

If it still annoys me I'm just going to weld a 1.5" pipe into the baffle hole and into the exhaust some to take out the long wavelength noise.

Frankly, it's all a bit shit and I wouldn't bother - just get a proper new exhaust.

Can't notice any difference in power across the range.
 
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poidabike

New Member
heavychevy69 said:
im still a little unclear, forgive me. so will this stock mod with a 2'' pipe cause me to run too lean and lose power?
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NO, the ECU is adjusting fuel all the time and will correct for things like exhaust pressure. The only thing an exhaust will change is the efficiency of the exhaust flow coming out of the head.

Back-pressure is just a bad way of explaining that you want the most uniform flow of air coming out of the heads and through the exhaust system.
 
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yellowfz

poidabike said:
NO, the ECU is adjusting fuel all the time and will correct for things like exhaust pressure. The only thing an exhaust will change is the efficiency of the exhaust flow coming out of the head.

Back-pressure is just a bad way of explaining that you want the most uniform flow of air coming out of the heads and through the exhaust system.
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I made my own exhaust tip (very easy by the way) and have been running it for over 18K miles no PCV or fueling adjustment of any kind and did not loose power or lean out past ECU adjustment parameters, I can get a 3rd gear wheel lift.
Doing a exhaust mod is simple, for about $40 dollars you can get a slip on mod done, I have detailed it several times about how to use reducer flanges and a short piece of pipe for the slip on tip all for about $40 dollars or less. Just buy a slip on tip of your choice.

Funny people talk about leaning out with mods, never think that each time they fill up the fuel may have different Ethanol content causing a leaning of AFRs, just a ploy to sell products. A PCV adds 2hp at most with a exhaust MOD maybe 4hp so you spend $1200-1800 for 4hp increase, not worth it.
 
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Ivan_13

New Member
So I'm looking at doing the mod with a 2 1/4 inch pipe. Would you guys recommend welding the pipe, and attaching an exhaust tip to that? Or just welding the new exhaust tip on there? I'm assuming it wouldn't make a difference right? I'm considering it, in case I can't to change the exhaust tip later on down the road.
 
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JT

Monster Member
Elite Member
Ivan_13 said:
So I'm looking at doing the mod with a 2 1/4 inch pipe. Would you guys recommend welding the pipe, and attaching an exhaust tip to that? Or just welding the new exhaust tip on there? I'm assuming it wouldn't make a difference right? I'm considering it, in case I can't to change the exhaust tip later on down the road.
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only dif would be aesthetic so do as you please
 
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poidabike

New Member
Ivan_13 said:
So I'm looking at doing the mod with a 2 1/4 inch pipe. Would you guys recommend welding the pipe, and attaching an exhaust tip to that? Or just welding the new exhaust tip on there? I'm assuming it wouldn't make a difference right? I'm considering it, in case I can't to change the exhaust tip later on down the road.
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Trust me, just buy a 2" exhaust tip, cut a 2"hole and weld it on. Recommend you protrude the 2" pipe into the chamber.

You can always go larger, hard to go smaller.
 
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poidabike

New Member
Piks of my 2.5" tip with internal cone and 1.5" hole added to reduce resonance. The wife is still looking for her nice stainless steel measuring cup...he... he... he.

Would have had the same result just going with a 2" tip.

Still to wrap fibreglass exhaust mat around the cone to stop air/noise leaking around the edges and also to absorb last remainder of resonance. Probably need to pull the cone out to do that, put the fibreglass mat in and perhaps rivet a stainless ring inside top hold it in place.
What a hassle.
 

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JT

Monster Member
Elite Member
poidabike said:
Piks of my 2.5" tip with internal cone and 1.5" hole added to reduce resonance. The wife is still looking for her nice stainless steel measuring cup...he... he... he.

Would have had the same result just going with a 2" tip.

Still to wrap fibreglass exhaust mat around the cone to stop air/noise leaking around the edges and also to absorb last remainder of resonance. Probably need to pull the cone out to do that, put the fibreglass mat in and perhaps rivet a stainless ring inside top hold it in place.
What a hassle.
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looks good man!
 
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Sascha

New Member
Just drilled some holes around the base of he small pipe.

So I just took the chrome piece off and drilled 6, 1/4' holes around the base of the small pipe and it sounds way better I will post pictures and video later today. So far lower tone and a little louder might add a few more holes later. The 6 I drilled I was able to do without removing anything but the chrome piece.
So far best easy mod for the bike.
 
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Ivan_13

New Member
Sascha said:
So I just took the chrome piece off and drilled 6, 1/4' holes around the base of the small pipe and it sounds way better I will post pictures and video later today. So far lower tone and a little louder might add a few more holes later. The 6 I drilled I was able to do without removing anything but the chrome piece.
So far best easy mod for the bike.
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:needpics:

And videos.
 
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heavychevy69

New Member
Going to get it done tomorrow, not sure this is going to work but saw it for 6$ so I snagged it 2&1/4 in and out, going to paint it black if it ends up fitting nice
 
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heavychevy69

New Member
now that i look at my bike this thing is obviously way too long haha, but it will have to be cut to fit anyways so maybe i can just use the slant part of the tip, and that should eliminate most of those nasty wrinkles in the bend anyways. hopefully the shop that welds it will have a better pipe sitting around
 

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