custom fab'd pipes and performance

[hotrdd]

This is the way my intake is setup right now. After reading this I'm going to put some pod filters on the bike and see if it runs any better. I can't relay explain it but it's just off. I'd love to be able to get that intake to work so I may do some research and see if I can measure the airflow on each side and how I can make it calm and smooth.

 

[hotrdd]

From the MAF sensor images on Google it looks like a piece of bug screen might actually work to calm the air down and make it steady. That would be an easy thing for me to try.

 

[kenbel]

I have made my own two into one header pipe with the lengths both being the same and fitted a Dunstall muffler to it with excellent results, the change in torque right through the gears is nothing but amazing and the sound after extra fitting of fibre glass is something else.

 

[TwoJugs]

The more I read, the less I know. Is it suppose to work that way?

 

[hoffman900]

The more I read, the less I know. Is it suppose to work that way?

Yep.

 

[rayth]

Gents
Love all your blogs - very interesting reading - especially the come backs lol
................
Have MikesXs Part #07-0767 header system with Part #07-0112 muffler fitted and have been given a ticket for excessive noise - Mind I might have got a cranky cop- but it does a fair holler when I crack it open
Appears that it has a fixed perforated baffle that I don't / cant want to change - the bore measures 44mm or so (1.75 inch) but was thinking if I were to MIG a round reducer plate of say 1 inch OR 1.1/4 where I can reach in that it might reduce the Db without changing the tune
She has Boyer system/ Mikuni VM34 carbs jetted as supplied ; plug color is loverly
Any advice gratefully received
Cheers from the Old Fart Downunder

 

[RatyXS]

The idea of stepped pipes, is to enhance the exhaust scavenge affect. The more efficient this can be done the more power you will make. I have not read all the pages, but this often gets thrown in with back pressure, they are not the same. If the engine has been tuned properly it will make the power.

 

[rayth]

Thanks John
But I was enquiring as to what size baffle I might add to my muffler "without" causing backpressure problems
Will not do anything until I get some advice
Just hope I don't get booked again
Cheers

 

[jimmy xscafe]

making a fast xs and rideable street xs are 2 different animals;i rude my xs 650 and get there fast on my cb1100f

 

[pa-powerstroke]

If I recall, Shell Thuet preferred 1.75" exhaust 29" long, straight pipe. Thats with a lot of engine work though.

 

[59Tebo]

I always thought the old classic cars with the visible, flexible, exhaust pipes were really cool (i.e. Cord, Mercedes Benz, Gazelle, etc.), and wondered how it would transcend to motorcycles, specifically our beloved Xs. I know it's been done to the sideways (V-twin) motors, but have never seen it on a horizontal twin. Shouldn't stainless be able to handle the heat, especially near the heads? And if I welded flanges (Okay, if I contracted somebody to weld flanges, I can only weld rabbit turds...) to flexible pipe, and connected it to rigid exhaust pipe, I should be able to construct exhaust systems of virtually unlimited configurations, right?
I ask, because the only exhaust system that will work with the plans I have for my build, exist only in my mind (like most of the other parts...). Has anyone ever used (and had success with) flexible exhaust pipe? Believe me, it would save a $#!t ton of fabrication if it worked...

 

[Marlin72xs]

I think you should ask Rube Goldberg. He can usually work out any problem. LOL.

 

[Cafe Murdock]

Is back pressure really a myth? There are those with defined opinions who would argue other wise. I guess Super Trapp got it wrong with their tunable disc mufflers which was designed to adjust the outlet volume to vary back pressure to bias power performance in the mid range or for maximum top end performance. The trick to any engine in allowing it to breath better is looking at reducing back pressure but without hurting performance,it's all a balancing act. What works for your engine may not be correct for another.

Bak pressure is not a myth it's real u can suck valves n all kinda other shit by running a motor with no exaust or to big or not enough pipe u can go straight pipe but u need to run smaller pipe or longer pipe it's a balancing act on straight pipe take a chalk box with motor cold snap a line fire it up n let it idle wen it cum to temp watch the line start to burn off like a fuse for a fire cracker wen it levels off n stops burning that's where u chop it off cuz that's the end of ur Bak pressure

 

[Gator xs2]

Very interesting there Murdock

 

[TwoManyXS1Bs]

Could run one of these...

 

[GLJ]

Bak pressure is not a myth it's real u can suck valves n all kinda other shit by running a motor with no exaust or to big or not enough pipe u can go straight pipe but u need to run smaller pipe or longer pipe it's a balancing act on straight pipe take a chalk box with motor cold snap a line fire it up n let it idle wen it cum to temp watch the line start to burn off like a fuse for a fire cracker wen it levels off n stops burning that's where u chop it off cuz that's the end of ur Bak pressure

For God's sacks. My grade school teachers would all spin over in their graves if I put together a sentence like that. It's obvious you can speak English learn to write it. I almost passed out trying to read your post.

 

[GLJ]

I already called him out on this. Believe it or not, the post you reference is an improvement!!

The REALLY funny part is that he's wrong about what he said. Not just how he tried to say it.

Check post #3.

What was that that Forest said"stupid is as stupid does"

 

[Cafe Murdock]

I race pro stock n late modules for years man we built everything we raced Bak pressure is a real tangable thing as sure as the sun rises in the east and sets n the west . If u don't believe me take any engine with straight pipes any engine chalk a line n watch for where the line stops burning if u don't believe me . I know for a fact where the stops burning is the end of back pressure plain and simple .

 

[Jack]

Bak pressure is not a myth it's real u can suck valves n all kinda other shit by running a motor with no exaust or to big or not enough pipe u can go straight pipe but u need to run smaller pipe or longer pipe it's a balancing act on straight pipe take a chalk box with motor cold snap a line fire it up n let it idle wen it cum to temp watch the line start to burn off like a fuse for a fire cracker wen it levels off n stops burning that's where u chop it off cuz that's the end of ur Bak pressure

Been wrenching and building engines a long time and I have a grasp of whats happing when building and tuning a exhaust system. You will always
encounter some form of trade off when it comes to exhaust, cams, airboxes,ect . It's about choosing the components and tuning that correlate in achieving
the power curve for your engine and intended usage.
I'm not about to sacrifice engine bottom end grunt for alittle extra HP in a RPM range that I'll never use. I tune my engines to the RPM range where
spend most of my time in street riding and BP plays an important role in assisting engine braking entering a curve in an attempt to ease up on using hand braking.
Straight piping will never outperform a well designed muffler that allows the gas pulse to expand and contract in assisting the scavenging effect.
Back Pressure(resistance) can be your enemy and can also be used for tuning. Have never burnt an exhaust valve either.

 

[grizld1]

Amen, solo and Jack! The problem with the term "backpressure" is that some use it in a way that confuses restriction and resonant pulse.