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Discussion Starter · #1 ·
Getting my head gasket fixed within the week but i'v been reading around the site and thinking about trying to get a yosi exhaust system. But my question is is there that much differance in a full yosi exhaust and a white bros (which i have on now--just the slip on) exhaust with a good header?
 

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Getting my head gasket fixed within the week but i'v been reading around the site and thinking about trying to get a yosi exhaust system. But my question is is there that much differance in a full yosi exhaust and a white bros (which i have on now--just the slip on) exhaust with a good header?
You might have problems if you get the wrong inside diameter on the header wrong. Slip on is meant to as the name says. "slip right on" the stock header. FMF makes a power bomb header that has a expansion chamber with the stock inside diameter of the rest of the pipe. If you buy a full Yoshi you will ring up around 200-400 bucks used. If you go buy the power bomb you will spend maybe 125-200 used. I had a white brothers e2 slip on for a while. Works with stock pipe. Though it did look like it needed a aftermarket header too. Idk, instead of spending all that money on a full system. Try out a FMF Powerbomb with your White Bros. ;)
 

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pro circuit's slip on silencer was the same as the full but they had a reducer bushing to mate it to the stock head pipe. i dont know if other companies did the same thing, that would make it easy for you.

to answer the other question, yes you will feel the header. slip ons dont do much more than make noise compared to a full system, and the cost isnt that bad for a full system. (woodward was having a sale on barker exhaust, he may still be doing that!)

keep your eye on the classifieds on here, something always pops up for a good deal. or sell your slip on and bite the bullet and go for a new full system. it will be money well spent.
 

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I've got a nice full yoshimura system up for sale in the classifieds.

Slip on's do nothing but make noise, if you do a search, there's a big thread on this.

You're better off with a full matching system, wether it be the one i'm selling or any other. Systems are designed to work with each other, combinations may not work as well or produce as much horsepower as a fully r+d'd system.
 

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Did a little google search and the source of this info was not the best but IN MY OPINION I think it's fairly accurate. At the end of the day........you really do want a full exhaust but here's some info on slip-ons.........

Purpose

  • A slip-on muffler functions similarly to a stock muffler, directing the spent exhaust gases away from the rider as they exit the motor. The main difference is in the path the gases must follow as they exit. A stock muffler incorporates a series of chambers and baffles to reduce engine noise and gaseous emissions, impeding the exhaust flow in the process. The straighter flow offered by a slip-on muffler allows spent gases to exit faster, helping to pull a fresh charge of air and fuel into the motor to generate more power.

Benefits

  • Slip-on mufflers, if designed to maximize the exhaust flow, will provide a subtle increase in the motorcycle's performance, with most gains ranging between 1 to 5 additional horsepower. Reduced weight, due to the lack of baffles and chambers, also helps performance by reducing the motorcycle's power to weight ratio.

Misconceptions

  • Many motorcyclists believe that a slip-on alone is enough to create more horsepower. However, air and fuel intake must be increased to compensate for the sudden increase in exhaust, which leans the air/fuel mixture by allowing too much oxygen out of the motor. If left as is, a lean condition will create a loss of power, and overheating will occur. Installing a high-flow air filter and an aftermarket fuel-injection controller or carburetor jet kit will balance the air/fuel mixture and generate more power.

 

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Discussion Starter · #6 ·
Thanks guys. Guess its time to sell the white bros and go for a full system. And biggie that yoshi looks pretty nice.
 

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I've got a nice full yoshimura system up for sale in the classifieds.

Slip on's do nothing but make noise, if you do a search, there's a big thread on this.

You're better off with a full matching system, wether it be the one i'm selling or any other. Systems are designed to work with each other, combinations may not work as well or produce as much horsepower as a fully r+d'd system.
Well that's debatable. :lol
 

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Well that's debatable. :lol
I'm not explaining it all over again. Do a search for scavenging, you'll find the answer to why a slip on pipe does nothing but make noise. If you're not changing the way the head pipe processes exhaust pulses, you're doing nothing to improve the efficiency of your exhaust system.

It's not debatable, it's factual.
 

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I've learned why slip ons only make noise haha.. Thanks for clearing that up big
 

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I'm not explaining it all over again. Do a search for scavenging, you'll find the answer to why a slip on pipe does nothing but make noise. If you're not changing the way the head pipe processes exhaust pulses, you're doing nothing to improve the efficiency of your exhaust system.

It's not debatable, it's factual.
So you're saying that a slip-on will make ZERO difference?
Even with the jetting, and change in filter?

I am by no means a mechanic but I stand by the belief that if you remove a stock muffler for a muffler with higher flow you are letting more air out. If you in turn let more air in and then correct the lean condition by properly jetting...............you WILL have more hp. Seem like common sense.
 

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I have a question.....if you put on a full exhaust and do not re-jet and do nothing to the air box will you pick up power or will the quad run to lean and not add power?
 

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so you can say......putting on a full exhaust and not re-jetting will not add the power it should. Wait is this kinda like the debate over a slip on. If you just put on a slip on and don't re-jet and help the air flow it will just make noise and not do much if anything for power.
 

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here is how I look at an exhaust....

do a slip on and re-jet and add more air will add some power not a lot but some. Will make the sound A LOT better. You can do all this for the price of the full exhaust.

do a full exhaust and re-jet and add more air will add more power then just doing the above with a slip on. It will of course cost more. If you EVER plan on doing any engine mods you want to do the full exhaust over a slip on.

I think this is pretty simple to understand
 

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I haven't been drinking yet so what I post is my opinion but I also welcome everyone elses input and facts:D If you put in just a K&N filter in your stock bike, or take lid off, you will feel better response but may have to go up a size main jet because of better air flow.

If you put just a slip on stock bike, you are hurting it if you don't go up a size on main jet because of loss of back pressure which the stock bike runs best at but it will be louder.

If you put just a full exhaust on a stock bike then you will run in a leaner condition because of more air flow and not enough fuel dispersion, so it will not run at it's best.

If you just go up on main jet on a stock bike then you will run in a richer condition and bike will not be at it's best.

You can't just do one thing to it and not compliment it with another, it will hurt the performance of the 400. As of yet there has been no dyno runs from adding one thing at a time like slip on, no lid, k&n, jetting etc.... Until then, there will be people here giving their input and some will be arguing.
 

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so you can say......putting on a full exhaust and not re-jetting will not add the power it should.

That is correct, in fact it will hurt your power and it will run hotter.

Wait is this kinda like the debate over a slip on. If you just put on a slip on and don't re-jet and help the air flow it will just make noise and not do much if anything for power.
That is also correct and will also hurt your power.
 

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Backpressure and flow are negligent when you're talking about the stock headpipe. You still have a less efficient headpipe producing a weaker scavenging effect. You could put a open piece of tin on the end of it and still not see any noticible gains until you get a tuned head pipe. On a dyno you'll see MAYBE 1hp difference with a slip on simply because it would ever so slightly aid the scavenging effect of the head pipe. In my book that's not worth $200+. If you're going to spend your money, and you actually want power, you need a full system.

Jetting is necessary with a full system, not so much with a slip on. The z may not have been optimally jetted to begin with assuming you've never adjusted the jetting before.

Any stock vehicle could benefit from jetting as they're set on the edge of too lean from the factory to keep the epa happy. That alone could give you the hp that you think you see from a slip on.
 

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The defense rests...........:lol

and I quote:

"On a dyno you'll see MAYBE 1hp difference with a slip on"
 

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Maybe, but it's from the re-jetting, not the slip on. I'd like to see a dyno result of a stock exhaust, then a slip on without re-jetting, then a stock exhaust re-jetted vs a slip on re-jetted.
 

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:z400rules:this is fun.


Biggie I agree with you 99.98946% (can't say 100% don't want you to get a big head)

For the $396 I spent on my Z400 and the difference in power over my second stock Z400 same year and I didn't have to break into the motor in any way, I'm very happy with the gains I got.
 
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