Gabe"s stock pipe mod

[HH400EX]

Can someone tell me where I can find it



Thanks

[DISHO1]

http://home.earthlink.net/~gellett/exhaust/index.htm

[Atomic83]

I'm fixing to get a yoshi pipe and wouldn't mind experimenting w/ this mod. How much power will it add, how much louder will it be.

[Wheelie]

Not trying to start anything here, but I tried that mod and didn't have good luck with it, it ended up blowing out the spark arrestor in a matter of minutes and I didn't notice much of a power gain. Ultimately I had to buy a new pipe after this to retain the spark arrestor.

Before I tried his mod I had one on my bike of my own creation that was quieter and in my opinion gave it a lot more power than stock and takes less time. You can check it out on my web site (http://w3.gorge.net/jeremiah/), look at the table to the left and you will find the link.

Any questions or problems please ask. I ran this setup for 3 or 4 weeks without a hint of trouble and it cost me $4 and I was beating piped EX's on comp. hill.

[4punksdad]

I tried a variation of gabes design.........and it worked well for me.

I removed the end cap from the stock pipe & cut the screened spark arrestor free from the end cap.

then I reached inside the pipe with a welder & cut 90% of the rear baffle plate out, leaving just enough to hold the original 3/4" orafice in place.

to cut with a welder, simply turn it up to max settings & use a very small rod..........it will blow a hole through most thin metals faster than a torch.

after I did this, I could see through my silencer from one end to the other without cutting it in half & welding it back together.

after putting the end cap back on the bike, I was done. The bike looks stock, says "spark arrestor" on muffler, sounds better (not too loud), and runs better. I too opened up my airbox and rejetted.

[Taco]

what did you rejet to 3punks?

that seems like a much better way to do it 3punksdad

punky brewsters dad..:D..did you have to cut the baffle plat into pieces to get it out or what...seems like that plate is to large to fit pull it out whole..also did you leave the end cap alone or modify that to the larger opening like wheelie

[86atc250r]

Keep in mind that when I did my pipe, the inner design was unknown to the internet community - it's easy to figure out better ways of doing it after you see the diagrams I made from cutting it open.

Another thing is the stock silencer has 3 chambers, by simply cutting the rear baffle, you turn it into a single chamber (since exhaust flows into the middle chamber first), which doesn't work really well for sound deadening. I kept all 3 chambers intact and opened each one up, which also took two 180 degree turns out of the exhuast path. This allowed the body of the silencer to still absorb/cancel some of the sound, while still flowing very freely. This pipe setup sounded very similar to the stock pipe, yet flowed much better and provided a good bottom and mid range power gain.

The way 3punks did it flows freely and is easier to accomplish, but likely outputs more noise, especially if the quietcore in the end cap is modified.

Also keep in mind that modifying the end cap will gain you NOTHING unless you work on the body of the silencer too.

Think of it this way - you have a 3/4" garden hose that flows 5 gallons per minute - would you screw on a 3" diameter tip on the end of the garden hose in hopes to get it to flow 10 gallons per minute? I hope not.

[4punksdad]

gabe,
you are right............the pipe is quite loud when revved up.............but if I want to stay off the fuel & creep through the woods undeteced, I can still do that. The bike sounds stock in the low & mid range..........it only barks on top end really.

I felt a more distinct power gain from my airbox mod than the pipe mod.

mgsucks,
the welder was cutting about 3/16-1/4" wide path while burning the rear plate............there wasn't much left after going around the edges.

the only mod I performed on my end cap was to cut off the spark arrestor screen.:)

tacostrk,
I rejetted to a 165

[86atc250r]

I felt a more distinct power gain from my airbox mod than the pipe mod.

As did I... The little things all add up...

With my pipe, the end cap became the limiting factor. Thru some testing we found that without the endcap, it ran as if there were no silencer at all. If I had the time and materials, I could probably come up with a design that was quiet and flowed well - maybe in the future....

while as soon as i get my motor back together we will see how loud my bike gets when i combine wheelies and gabes(treepunks dads style...think it might flow to much and have no back preasure or what cause i don't wanna mess anything up

[4punksdad]

Originally posted by McgrathSucks
while as soon as i get my motor back together we will see how loud my bike gets when i combine wheelies and gabes(treepunks dads style...think it might flow to much and have no back preasure or what cause i don't wanna mess anything up

try it out...heck, you might come up with a better idea than all of us combined!