[dewby]

i want to make a motogp style slip like darkhorses lean pipe but i want it to have some back pressure and not be so load, so i designed this.
the three solid black things are washers, the one in the middle is just a stopper that stops on the stop ring on the stock headers. the other two washers free sliding, i am hoping to have the ability to move it so i can adjust the sound like a trombone. when i find the noise i want just tac weld it into place. the bottom and top washers are attached to a perforated tube witch i'll wrap with muffler fiber glass. i didn't want the slip on to be too long, i feel like it would take away from the look i am going for so i think i am going to run the perforated tube down the stock exhaust tube. if the setup causes to much restriction i'll just drill holes into the washers. any input would be great. do you think the fiberglass will help with the sound deadening and backpressure? i shimmed my needles about 2mm do you think this will me out to much?

 

[Racer X]

One thing to think about is resinance. You may loose bottom end power .I never rode delow 9000rpm.

 

[dewby]

well i was hoping the fiberglass and washers would help with the resistance. would it not? i really don't know a whole lot about this kind of stuff.

 

[Jester]

Darkhorse was talking about resonance, not resistance.

 

[Racer X]

I cant explain it . I know there are charts and graphs for exhaust tube length. And collector position. It is something I wish I knew more about . It dose not matter any how . Just make it and try it out .What have you got to lose .
It will look great and sound wild . If yo want you could also use a wrap on the pipes to quiet it some .

 

[dewby]

ahh, sorry i just thought it was a typo lol. happens to me all the time.
what do you mean wrap on the pipes?

 

[Racer X]

Like an fiberglass cloth that wraps around the pipes . It keeps the heat in which is another thing about exhaust systems and efficiency .But it will quiet down the noise a little.
http://www.thermotec.com/exhaust-insulating-wrap.html?gclid=CP6tlruAsJgCFQHHGgod2icfVA

 

[dewby]

ya i ordered some off ebay. my friend said steel wool would work, any one ever try streel wool?

 

[Jester]

I think fiberglass is supposed to be better

 

[dewby]

that's what he said but he was like fiberglass will last like 7000 miles vs steel wool equals 15 years. lol i dunno he is like a 50 year old man that makes pressure vessels when he talks i listen, he is a lot smarter than me.

 

[Racer X]

That is the best way .
Listening will get you farther in life than talking

 

[dewby]

true dat dark.

 

[spooph]

I do also think that steel wool is a little more difficult to spread evenly, whereas fiberglass just wraps nice and even... Steel wool is also quite a bit heavier. If you're worried about back pressure, why not design a spring loaded flap inside the perf. tube. Kind of like a buttefly, but with a hing on one side, and a spring attaching it to the valve... then all you have to experiment with is how heavy the spring needs to be to open at the desired RPM...

This way you'd be making a cheap mechanical copy of yamaha's EXUP system, which basically means, with the right weight spring, you could keep your low-end back pressure, and have a straight-through pipe for the high end...

I think you do want to keep as much mid-range as possible, being that the stock cams are worked that way.... Now if you added eccentric cams and stuff, by all means, screw the back pressure and low/mid range... But that's a lot of money...

what do you say Darkhorse?

I'm also with the Dark, build it and see, and keep us posted with picts..

 

[dewby]

i am not sure if i am clever enough to do that. thats a bit beyond my means, but my buds brother is a motorcycle guru so maybe he can help me with that. i haven't asked him about the pipe yet been meaning to just to busy. but very clever and thankie spooph

 

[dewby]

maybe a thermostat for a car would work for this?

 

[dewby]

 

[crushedcamber]

wow, that looks good, i would love to have that, i thought about making one like that but i decided to go regular style... so if you make it and it works, ill buy one...

 

[spooph]

It's gonna be loud man, a lot louder than the $36 muffler...

 

[dewby]

does anyone have anymore ideas on how to diffuse this exhaust slip on, maybe some more washers at different angles etc.

 

[Guest]

I heard of this trick somewhere. Go to a machineshop. Get some big handfulls of steel chips. The kind that look like barbed wire. Stuff those into the spaces inside the muffler/pipe. Or steel pot scrubbers stuffed inside.
Sleepy