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Discussion Starter #1
If there is anyone still out there like me with the stock muffler but still looking for an upgrade, here's a cheap DIY mod which in my opinion is well worth it. Sorry i don't have any hard numbers for hp gain, but i'm guessing it's 3/4 to 1 along with an open air box. Plus it sounds sick! enjoy!

- cut out stock exhaust hole/bent pipe peice to 1 3/4 in.
- cut off spark arrestor from assembly that bolts in the middle of the can in order to still use that piece...don't cut it flush, leave about an inch of pipe.
- fabbed 1 3/4in. pipe to run from newly cut middle bolt-in piece (flared to slip over that in. or so you didn't cut off) to new end cap 1 3/4 in. exhaust hole...welded only at the end cap.
- bolt everything back up using the stock perforated core in the front end of the can with new packing.

it sounds like a high end exhaust....not even close to stock.
 

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Looks alot like the mod I did, it made 3/4hp more on the dyno, made mine so a yoshi quiet core/sparky would work with it...
 

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Discussion Starter #4

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This is by far the best modded stock exhaust I have ever seen. Instead of just pulling out the sparky and leaving air to tumble around in the end cap, (bad for flow/performance IMO) the air is directed right out the exhaust cap for optimal flow.

Hopefully it will be on the dyno in a month or so and show better gains than the more common mod for the stock exhaust does.

I have heard it in person and it sounds excellent, also.

He also got the header flange welded and that stopped the popping on decel, too.
 

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If there is anyone still out there like me with the stock muffler but still looking for an upgrade, here's a cheap DIY mod which in my opinion is well worth it. Sorry i don't have any hard numbers for hp gain, but i'm guessing it's 3/4 to 1 along with an open air box. Plus it sounds sick! enjoy!

- cut out stock exhaust hole/bent pipe peice to 1 3/4 in.
- cut off spark arrestor from assembly that bolts in the middle of the can in order to still use that piece...don't cut it flush, leave about an inch of pipe.
- fabbed 1 3/4in. pipe to run from newly cut middle bolt-in piece (flared to slip over that in. or so you didn't cut off) to new end cap 1 3/4 in. exhaust hole...welded only at the end cap.
- bolt everything back up using the stock perforated core in the front end of the can with new packing.

it sounds like a high end exhaust....not even close to stock.

is there anthing done to the head pipe
 

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Discussion Starter #7
is there anthing done to the head pipe
nope, nothing done to the head pipe other the flange piece welded to eliminate popping on decel
 

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This is by far the best modded stock exhaust I have ever seen. Instead of just pulling out the sparky and leaving air to tumble around in the end cap, (bad for flow/performance IMO) the air is directed right out the exhaust cap for optimal flow.

Hopefully it will be on the dyno in a month or so and show better gains than the more common mod for the stock exhaust does.

I have heard it in person and it sounds excellent, also.

He also got the header flange welded and that stopped the popping on decel, too.

We dynoed one just like this. Almost 1whp over stock. Nice mod for sure. ranchero did his like this.
 

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We dynoed one just like this. Almost 1whp over stock. Nice mod for sure. ranchero did his like this.

I was unaware anyone had done a mod like this. This isnt your standard modded stock pipe where they just pull/cut the sparky out. Which is horrible for performance IMO because the last half of the pipe has no direction for the air to go. Air just tumbling around in an empty half of of a canister with a less than 1" exit sounds and performs like crap.

This pipe has a full piece of pipe running from the first half of stock perforated packed pipe. Mandrel bent and TIG welded to the opened up stock end cap. I need to talk him into getting a video with a sound clip up because IMO it sounds 100X better than the stock pipe.

I believe he's already broken the speed of sound twice. :p
 

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Discussion Starter #11
what jetting are you using for this pipe. I just did the same thing and was wondering where you started at.
i have the JD jet kit with the 185 main and 45 pilot....red needle as it comes in the kit. F/S turned 1 1/2 out.
 

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If there is anyone still out there like me with the stock muffler but still looking for an upgrade, here's a cheap DIY mod which in my opinion is well worth it. Sorry i don't have any hard numbers for hp gain, but i'm guessing it's 3/4 to 1 along with an open air box. Plus it sounds sick! enjoy!

- cut out stock exhaust hole/bent pipe peice to 1 3/4 in.
- cut off spark arrestor from assembly that bolts in the middle of the can in order to still use that piece...don't cut it flush, leave about an inch of pipe.
- fabbed 1 3/4in. pipe to run from newly cut middle bolt-in piece (flared to slip over that in. or so you didn't cut off) to new end cap 1 3/4 in. exhaust hole...welded only at the end cap.
- bolt everything back up using the stock perforated core in the front end of the can with new packing.

it sounds like a high end exhaust....not even close to stock.
look at the picture attached
do you remove # 3 from the can and run only front packing (#4)
i trace a line on it do you cut everything after this or you leave what seem to hold #3 in place in the can
thanks you and it is really loud or its resonable level (-100db)
 

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I just knocked the sparky out of the pipe with a punch and it seems to work well and its not too loud
 

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What type of material do you guys use for the 1.75" tube? Aluminum?
 
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