Author Topic: Str8 Pipe, Anyone?  (Read 2418 times)

jprestonian

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Str8 Pipe, Anyone?
« on: June 14, 2012, 02:18:33 AM »
Two questions:

1.) Anyone ever thought about having a muffler/custom shop make them a straight pipe for their scoot?

2.) Why I ask: My P250's exhaust has a big enough leak now to sound TOTALLY AWESOME. Think Buddy Blackjack + Prima pipe on testicle-shrinking, bodybuilding steriods.  ;)  That sucker has some bass notes you wouldn't believe. However, I am concerned about screwing up my exhaust valve by not immediately addressing this (payday is next Friday, ugh). How concerned should I be about damaging the valve?
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Vivo

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Re: Str8 Pipe, Anyone?
« Reply #1 on: June 14, 2012, 02:43:50 AM »
I had a bike with a loud pipe before.


The loud noise is cool if you're standing and the bike passes by...

But riding on a loud bike all day is a different story...

my opinion...

zombie

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Re: Str8 Pipe, Anyone?
« Reply #2 on: June 14, 2012, 02:49:58 AM »
How far back from the valve is the break, and about what diameter pipe? 6" on a 20mm pipe should be safe. 3/4" pipe would need as much as 9-10".
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streido

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Re: Str8 Pipe, Anyone?
« Reply #3 on: June 15, 2012, 08:24:24 AM »
I thought about getting a stainless straight-thro pipe made up in our pipe shop at work. Could get it done for free if i gave in a template or sample of exactly what i wanted. The only thing that put me off was that i wasnt sure about the whole back pressure thing?

Im sure i read that a scoot needs that pressure or it can burn up the valve or something? Maybe im mistaken, sure i read someone had ran their scoot with no exaust as it "sounded awesome" but others had replied about the pressure thing and told him he would burn up his engine like that. I assumed a straight pipe would give a similair effect to running no pipe?

Anyway, i just fitted a Leo Vince this week in place of stock instead, at least for now, that gives a lovely burble, my 50cc Agility almost sounds like a powerhouse now and i feel i gained a little mid-range power too (may just be the cool noise messing with my brain tho).

One thing tho, at 1st i wasnt sure i could live with the extra noise every day, i even almost got some ear plugs. Now ive ran it a few days i have got more used to it and it isnt so over bearing on my ears, i can kinda zone it out now on longer rides.
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zombie

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Re: Str8 Pipe, Anyone?
« Reply #4 on: June 15, 2012, 08:51:37 PM »
Zero back pressure is zero pipe. Even 1 inch of pipe has some pressure from forcing the direction of the gases. The exhaust is cooler than the combustion chamber so ANY gas's left in the pipe cool the open valve edges.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

streido

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Re: Str8 Pipe, Anyone?
« Reply #5 on: June 15, 2012, 09:32:31 PM »
Zero back pressure is zero pipe. Even 1 inch of pipe has some pressure from forcing the direction of the gases. The exhaust is cooler than the combustion chamber so ANY gas's left in the pipe cool the open valve edges.

So on theory in could get a fancy stainless pipe made up and run it on my 4t A50 then and it'd be ok?

Fancied maybe trying to get something that would exit out the middle, under my seat, that'd look cool as it sounded  :)
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zombie

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Re: Str8 Pipe, Anyone?
« Reply #6 on: June 15, 2012, 09:37:55 PM »
Anything over 1 foot in length will be safe, and better power. Thinner pipe will boost low end, and wider pipe is best for top end.
If you were to make one I would go oem pipe diameter (no muffler)to get the most boost out of it.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

streido

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Re: Str8 Pipe, Anyone?
« Reply #7 on: June 15, 2012, 11:37:24 PM »
Anything over 1 foot in length will be safe, and better power. Thinner pipe will boost low end, and wider pipe is best for top end.
If you were to make one I would go oem pipe diameter (no muffler)to get the most boost out of it.

Cool, and i just so happen to have my old stock pipe i took off on Tuesday, was going to bin it anyway so i can use that as a template for the downpipe, im half way there already......just need to buy some cakes to bribe the pipeshop manager now  :D
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zombie

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Re: Str8 Pipe, Anyone?
« Reply #8 on: June 16, 2012, 05:03:05 AM »
A custom pipe should be cake for an experienced bender. After getting the bends from your template you can cut off the old flange to attach to your new pipe. Stainless can be welded to mild steel with a TIG, and the correct rods. I just had a stainless bung welded to my mild steel pipe for the EGT probe. I would LOVE to find out if the Scorp. pipe can be made one off in stainless.
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zombie

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Re: Str8 Pipe, Anyone?
« Reply #9 on: June 16, 2012, 05:06:51 AM »
Oh Hey.... Those Ebay sellers that sell 50cc GY6 exhausts all sell header pipes for around 30.00 shipped. http://www.ebay.com/itm/130601793421?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649  This guy in particular. Tell him Zombie2009 referred you.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

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