 Straight Pipes
|
Joined: Jun 2007
Posts: 529
Adjunct
|
OP
Adjunct
Joined: Jun 2007
Posts: 529 |
I still have the stock pipes from my '07 and want to completely gut them out and put them on my '05. I found a local mechanic that will gut them for a great price. What I want to know, other than having to rejet, are there any negatives to running straight pipes on our bikes? Long term health of my power plant is way more important than short term performance.
2005 America, green/gray, gutted stock pipes, tall sissy bar w/ luggage rack, Saddleman's dual touring seat and Tourmaster saddlebags (and sissybar bag).
|
|
|
Re: Straight Pipes
|
Joined: Jan 2005
Posts: 3,753
Loquacious
|
|
Loquacious
Joined: Jan 2005
Posts: 3,753 |
lose of power, you need some backpressure. there are instructions in here that make it easy to do yourself. check it out
Frank
(Former)05 BA tbike pipes, ai removed, Freak, mikuni hsr 42's, 904, ported/polished head, 1mm oversized valves
NOW-2010 silver and black tbird
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
If you gut stock pipes be sure to leave the reducer cone in the end where they attach to the header and you won't lose bottom end torque.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Jul 2008
Posts: 1,440
Learned Hand
|
|
Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
If you gut stock pipes be sure to leave the reducer cone in the end where they attach to the header and you won't lose bottom end torque.
If I'm cutting the baffles away with a tool from the outlet end, is there a way to know when I'm about to hit the reducer? Or is this the sort of thing that's obvious once you're into the job?
Jack
'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy
|
|
|
Re: Straight Pipes
|
Joined: Jan 2005
Posts: 570
Adjunct
|
|
Adjunct
Joined: Jan 2005
Posts: 570 |
I've just taken out 3 complete baffles [each side] on my '07 Speemaster and really like the rumble I've achieved so far. There is one more baffle left that I might drill a couple holes in some day down the road. As I understand it, behind the fourth baffle is the "Cat" and then the reducer cone. I'm leaving all that in to keep the back pressure Dog talks about. You won't be sory with the Triumph "Note" you achieve.
"You're a long time underground!"
|
|
|
Re: Straight Pipes
|
Joined: Jun 2007
Posts: 529
Adjunct
|
|
OP
Adjunct
Joined: Jun 2007
Posts: 529 |
Another novice question: what all is in a stock pipe? Number of baffles, a cat, reducing cone?? Someone let me know what's all in there...lol.
2005 America, green/gray, gutted stock pipes, tall sissy bar w/ luggage rack, Saddleman's dual touring seat and Tourmaster saddlebags (and sissybar bag).
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
I have seen at least 3 different pipes now as far as contents go. Some of the older pipes before the cat had 3 baffles and others had 4. Later pipes had the cat in them and I guess 4 baffles from what Shutterbug says. (I haven't been in a set with a cat yet.) Then there are the pipes in the bafflectomy thread, The cone in those appears to be more than a cone.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Aug 2008
Posts: 1,048
Learned Hand
|
|
Learned Hand
Joined: Aug 2008
Posts: 1,048 |
Quote:
lose of power, you need some backpressure. there are instructions in here that make it easy to do yourself. check it out
Frank
Any evidence of this documented? I always here people say this, but logically it makes no sense. I mean an engine is an air pump. The less restriction the better. Now if there is some reversion in the pipes, or it ruins the scavenging effect I understand, otherwise I don't.
It's not true anywhere in physics so there must be something OTHER than back pressure reduction going on. NO engine NEEDS back pressure.
Clay
PS I'm not picking on you in particular. I'd just like to know what is happening really.
Last edited by frijoli; 09/21/2008 6:18 PM.
|
|
|
Re: Straight Pipes
|
Joined: Jul 2008
Posts: 1,440
Learned Hand
|
|
Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
Any evidence of this documented? I always here people say this, but logically it makes no sense. I mean an engine is an air pump. The less restriction the better.
This stretches my memory a bit, so don't quote me. The effect has to do with valve overlap. If flow in the exhaust pipe is unrestricted, the intake charge is diluted by the old combustion products. The effect disappears at higher RPM because there's insufficient time during the overlap period for the exhaust gas to reenter the chamber. This effect of overlap and dilution is also the reason racing cams require such extremely rich idle mixtures and produce little low end torque.
Jack
'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy
|
|
|
Re: Straight Pipes
|
Joined: Nov 2007
Posts: 1,883
Learned Hand
|
|
Learned Hand
Joined: Nov 2007
Posts: 1,883 |
The new pipes on my '07 speedie, are practically straight, and I have noticed a loss of power, not a lot but some. It sounds amazing,but I am ordering a baffle to put in the pipe that will hopefully help a bit.
I did take the bike in to make sure it was jetted correctly, it backfires like crazy, especially on deceleration, and when the engine is cool. The shop suggested, some back pressure in the pipes should help the backfiring. Any thoughts?
~Brent
-----
"Nothing you can be is more terrible than what I am." ~ 2007 Black Speedmaster!!
|
|
|
 Re: Straight Pipes
|
Joined: Jun 2006
Posts: 2,626
Loquacious
|
|
Loquacious
Joined: Jun 2006
Posts: 2,626 |
I changed my stock mufflers for JCWhitney 16" shorties, a straight-through pipe. I haven't really noticed any loss at the bottom end. I think if there was any loss of power it's offset by the loss of weight, about a case of beer's worth. 
Steelheart- '03 Speedmaster Black/Yellow
The Hayabusa Killa
16" Shorties/140 mains/Airbox drilled
Procom CDI
"There is no cure for Celibacy. But we can treat the symptoms."
|
|
|
Re: Straight Pipes
|
Joined: Jul 2008
Posts: 1,440
Learned Hand
|
|
Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
it backfires like crazy, especially on deceleration, and when the engine is cool
That sounds more like mixture than a need for backpressure. You probably need main jets about 127-130 if there are no other mods. Check Pat's jetting calculator.
Jack
'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
This could also indicate an exhaust leak somewhere.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Nov 2007
Posts: 1,883
Learned Hand
|
|
Learned Hand
Joined: Nov 2007
Posts: 1,883 |
Hey Jack and Dog, I was wondering about the jets. Is that something I can tell the shop to replace? I asked them, based on this board, to see if I need to rejet, they said no. Do I need to tell them what sizes to use, and that I want them replaced? They put it on the Dyno(?) and they said it was perfect. I don't really know what that means. I am running totally stock otherwise. I have not removed or disconnected the Air Intake. Should I? Dog, when I had it at the shop earlier this month, they checked for a leak, to make sure I had installed the pipes correctly, I don't think it is a leak. I am pretty mechanically impaired, as Soren can attest. Brian I also got my pipes from JCW (with your help) and they went on easy, but you have never had any backfiring problems? Did you rejet?  Thanks for all of the responses, it always get me to thinking...and that's never any good for the wallet. Take Care, Brent
~Brent
-----
"Nothing you can be is more terrible than what I am." ~ 2007 Black Speedmaster!!
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
If they have a sniffer on the dyno and it was far up the pipe as it should be then trust the dyno. Ask for the read out , even better if you could have witnessed the test and saw the read out first hand. If you trust them to be honest then take their word if they put it on the dyno and said it was good. Might ask them what the mixture was at several different RPMs across the range just to verify they know what they are talking about. Bottom line is the dyno with a guy who knows how to use it is the best way to set your mixture.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Jul 2008
Posts: 1,440
Learned Hand
|
|
Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
They put it on the Dyno(?) and they said it was perfect.
Straight pipes represent a drastic change for a motor that's set up for stock pipes. You certainly need to rejet the mains, and it's almost inconceivable that a dyno test wouldn't demonstrate this right away. I'm wondering if there might be a problem at the dealership, and if so, I woudn't trust them to work on the carbs. Maybe there's an independent service guy in your area who can change the jets for you. This is a simple job for any bike mechanic familiar with carbureted parallel twins.
Jack
'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
Quote:
Quote:
They put it on the Dyno(?) and they said it was perfect.
Straight pipes represent a drastic change for a motor that's set up for stock pipes. You certainly need to rejet the mains, and it's almost inconceivable that a dyno test wouldn't demonstrate this right away. I'm wondering if there might be a problem at the dealership, and if so, I woudn't trust them to work on the carbs. Maybe there's an independent service guy in your area who can change the jets for you. This is a simple job for any bike mechanic familiar with carbureted parallel twins.
Jack
True and if the jetting is stock go somewhere else where they will do it right.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Jun 2006
Posts: 2,626
Loquacious
|
|
Loquacious
Joined: Jun 2006
Posts: 2,626 |
Quote:
Brian I also got my pipes from JCW (with your help) and they went on easy, but you have never had any backfiring problems? Did you rejet?
I haven't rejetted, but I should. I get the old PAP-PAP-PAP on decell, but that's from the AI.
I ride almost everyday, it's my only transpo, so I'm reluctant to tear into a bike that's working reliably.
I know there's untapped power in there, though.
Last edited by BrianT; 09/26/2008 9:59 PM.
Steelheart- '03 Speedmaster Black/Yellow
The Hayabusa Killa
16" Shorties/140 mains/Airbox drilled
Procom CDI
"There is no cure for Celibacy. But we can treat the symptoms."
|
|
|
Re: Straight Pipes
|
Joined: Feb 2007
Posts: 23,248 Likes: 64
Fe Butt
|
|
Fe Butt
Joined: Feb 2007
Posts: 23,248 Likes: 64 |
That's bad Brian, you will eventually burn a valve if you are too lean. Jetting is very easy and not worth your engine to keep putting it off. Even a first time and pulling the carbs to boot should only take a few hours at most.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
|
|
|
Re: Straight Pipes
|
Joined: Jun 2006
Posts: 2,626
Loquacious
|
|
Loquacious
Joined: Jun 2006
Posts: 2,626 |
Maybe the dirty air filter is keeping it from being too lean. 
Steelheart- '03 Speedmaster Black/Yellow
The Hayabusa Killa
16" Shorties/140 mains/Airbox drilled
Procom CDI
"There is no cure for Celibacy. But we can treat the symptoms."
|
|
|
Re: Straight Pipes
|
Joined: Jul 2008
Posts: 1,440
Learned Hand
|
|
Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
True and if the jetting is stock...
Well Gawl-Dang... at least we agree on something. 
|
|
|
|
|
