Exaust design's (single vs. dual) Help

[wastedincome420]

Bike in question is my: 86 honda VFR 700 w/ V4
I'm qustioning whether 4-1 or 4-2 exaust is better
I'm sure that it all has to do w/ the type of engine,etc...BUT I AM asking bout a V4.........
Currently the bike has a old (discontinued) Yoshi' 4-1 system on it. But it has some leaks and I think a few of the header pipes may be bent a bit.
The shitty part is there's like NO body (descent) that makes exuast. So I think I'm forced to custom make a system (likely using the yosh as a guide). I figured I start off w/ picking a good can and go from there.
So any help on which design will be better for my bike?? what kinda cans should i look at??

[benVFR]

I believe 4-2-1 or 4-1 is best for the VFR.

The duals on the 02-04 model VFR is considered kind of silly by most.

VFRdiscussion.com should have the answer... ?

Ben

[Mad Max]

If you are going to make it custom, why not go 4-4?

[benVFR]

The idea being that for this engine configuration 4-2-1 or 4-1 are the optimal configurations.

AFAIK only twins benefit from having more than one exhaust pipe.

TLRMan and some of the other members can/have explained the technical reasons before.

Ben

[Karaya One]

The Honda RC-45 went through several different pipe designs through its years of service.

This included 4-2-1, 4-2-2, 4-1-2 and 4-1-1.

Even the WSB Muzzy Kawasaki tried a 4-1-2 at one time for Hockenheim.

You should go back and look at what the factory RVF750 Honda's ran back then in 85-87 in both World Endurance and F1. I believe it was a 4-2-1.

[02SuperHawkRdr]

I vote put on whatever came OEM. We're talking a nearly 20 year old bike here. Why spend extra time/effort/money when it's not going to do all that much extra for you?

[Stoneman]

Let's be honest here. There's about one chance in a million that the everyday layman will design and build a homemade exhaust that will even allow the bike to run properly, never mind run good. Doesn't matter what you use for a can. A TON of R&D goes into ANY exhaust, and there's a long list of reasons for this. Some quick research shows that there IS a coupla manufacturers out there that still have exhausts avaliable for your bike. I say bite the bullet and BUY one...

I'm not doubting your 'do it yourself' abilities. But this is not simply a 'bend it and install it' deal. This is NOT a project you should undertake unless you have devices that can measure back pressure, the effects of your exhaust on the exhaust valves, and an exhaust analyzer...

[beet]

stock exhaust on your bikes not that bad
even the best AM exhaust might make 2 hp more power only in the high rpms & loose 6 hp in the band you mostly drive in
if its just for noise then unstuff some packing out a your cans makes um fart
you dont need a big ass hole 1 fart good

[Paul_E_D]

I disagree that you can't make a good system at home. What you must copy carefully from a known "good" exhaust is the pipe diameter and EXACT length. Bend it pretty much any way you like, as long as the bends aren't 90 degrees or anything, you'll get pretty much exactly the same performance as the professional pipe. If you take your time, you can get some very trick looking pipes. On VFR, however, you're not going to see them

[wastedincome420]

Originally posted by Stoneman
Let's be honest here. There's about one chance in a million that the everyday layman will design and build a homemade exhaust that will even allow the bike to run properly, never mind run good. Doesn't matter what you use for a can. A TON of R&D goes into ANY exhaust, and there's a long list of reasons for this. Some quick research shows that there IS a coupla manufacturers out there that still have exhausts avaliable for your bike. I say bite the bullet and BUY one...

I'm not doubting your 'do it yourself' abilities. But this is not simply a 'bend it and install it' deal. This is NOT a project you should undertake unless you have devices that can measure back pressure, the effects of your exhaust on the exhaust valves, and an exhaust analyzer...

You DO bring up some valid points here Jay...But I wasn't planning on taking some pipe and bending it around a tree out back or something...............
I'll have to take a pic but the design of the pipes on my my bike are VERY simple.
So what did YOU find for "pre-made" systems??

Heres they way I see it: If the exuast that I have on it now has leaks,etc it aint performing the way it should to begin with

[wastedincome420]

Originally posted by beet

stock exhaust on your bikes not that bad
even the best AM exhaust might make 2 hp more power only in the high rpms & loose 6 hp in the band you mostly drive in
if its just for noise then unstuff some packing out a your cans makes um fart
you dont need a big ass hole 1 fart good

Beet you really crack me up....
I'm NOT looking to get he exaust any louder....In fact it wouldnt break my heart to quite it down a bit.

[wastedincome420]

Originally posted by Paul_E_D
I disagree that you can't make a good system at home. What you must copy carefully from a known "good" exhaust is the pipe diameter and EXACT length. Bend it pretty much any way you like, as long as the bends aren't 90 degrees or anything, you'll get pretty much exactly the same performance as the professional pipe. If you take your time, you can get some very trick looking pipes. On VFR, however, you're not going to see them

Thats pretty much what I was thinkin..... I wasnt planin of just throwing together a bunch of pipes. I was thinkin of using the Yoshi' as a template.

[Awesome]

I'll have to side with Stoneman on this. I recently read a very in depth book on performance sportbike tuning. Template or not, you're not going to be replicating any research or tuning at all on your bike. You're taking a shot in the dark and there's in no way you'll be able to measure or adjust to how a homemade system will effect back pressure and such things. If it were so simple don't you think you'd have heard of more people or racers having custom systems built? Why spend 800 on a full system if you could just copy your friends with some pipe and a bender from home depot?

[Paul_E_D]

MANY racers have custom built exhausts. I have one on my Ducati. It works as well as most aftermarkets, and better in some ways (mid range and torque) It was cheaper than a name brand full system and looks killer. (actually, it was cheaper than some aftermarket cans alone!)

Admittedly, the guy who built it had MANY hours of development work on the dyno, but it ain't rocket science. Length of headers, pipe diameter and taper, and collector style are really the only factors.

Canisters make little difference in HP as long as there is and end cap, they are all roughly the same. Bigger can = quieter exhaust.

The whole expansion chamber concept in 2 strokes came from guys building their own systems through trial and error. No science involved whatsoever. In fact, it's still difficult for them to explain why some pipes work better than others.

If you used the same basic dimensions as a known product, you can lay it out any way you like and get results that are nearly identical. Especially for a street bike, I think it would be a fun and rewarding project. You're not exactly squeezing that last HP out of a VFR on the banks of Daytona anyway.

I say GO FOR IT! Post the pics of your progress.

[Rye]

Pipe bending and flare tools can be had for very cheap too!

[wastedincome420]

Originally posted by Rye
Pipe bending and flare tools can be had for very cheap too!

Hey Rye How ya been
Well I was thinking of leaving the actual bending & flaring upto a Pro to do...

PS: You happen to have a pic of the front of your bike (showing headlites)

[wastedincome420]

I'm gonna have to take some pics of the exaust I have now...It'll show that it didnt really seem like much R&D went into it....

[Dianne]

Tons of websites to buy exhaust from...

Less time fooling with exhaust on bike means more time for ???? And, oh yeah, more time for riding the bike too.

[Rye]

Originally posted by wastedincome420
Hey Rye How ya been
Well I was thinking of leaving the actual bending & flaring upto a Pro to do...

PS: You happen to have a pic of the front of your bike (showing headlites)

Not bad. I don't have any with the bike in street trim but that can be seen all over the net. Type a search for 93-95 ZX7 and your bound to find a snap. Why? If your planning on grafting the nose, be sure you will know all the costs involved!

[RandyO]

Glad to hear you doin well Rye.....
Well I was more or less thinkin bout using a double round headlite set up...Still unsure

[Rye]

It will be a pain Randy. You'll have to use the existing mount on the lights which may not correspond close enough to the Honda's mount. Wait....for the SV or the VFR? If SV, and you only want the lights from a ZX7, I'd say it could be done with some creativity. You also have the option of using early CBR900RRRRRRR lights also. The ZX7's were round and in a solid fixture from the years 91-95. The 96+ ZX's have the "Asian Eye" lights that would not really offer a nice bikini style dual setup. Or, maybe a place like Baja Designs would sell a real dual sport setup which would light the road up like a landing strip (helpful for your dual-sport type riding). The only issue may be with the weak charging systems common to our bikes. I t may require a stator rewind to up the juice. Just speculation of course. Let me know how it goes.

[TLRMan]

Originally posted by Paul_E_D
The whole expansion chamber concept in 2 strokes came from guys building their own systems through trial and error. No science involved whatsoever. In fact, it's still difficult for them to explain why some pipes work better than others.

I'll totally agree on this one...Heat, and where the pipe is in the airstream makes a difference...there is some science involved but more mathematics....but when you build the pipes, you need to know rpm's, exh temps, exhaust timing, etc. Playing with stinger lengths and diameters, make a lot of differences too, as well as belly size/length, and cone angles...Been there....

Look up Dr. Gordon Blair, he teaches at university Belfast....The guy is a genius...

[wastedincome420]

Originally posted by Rye
It will be a pain Randy. You'll have to use the existing mount on the lights which may not correspond close enough to the Honda's mount. Wait....for the SV or the VFR? If SV, and you only want the lights from a ZX7, I'd say it could be done with some creativity. You also have the option of using early CBR900RRRRRRR lights also. The ZX7's were round and in a solid fixture from the years 91-95. The 96+ ZX's have the "Asian Eye" lights that would not really offer a nice bikini style dual setup. Or, maybe a place like Baja Designs would sell a real dual sport setup which would light the road up like a landing strip (helpful for your dual-sport type riding). The only issue may be with the weak charging systems common to our bikes. I t may require a stator rewind to up the juice. Just speculation of course. Let me know how it goes.

Hey Rye....Sorry but the message above was from ME and NOT RandyO..... I was considering double round headlites for my VFR But not so sure now.
Who knows what Randy really wants to do w/ his lites

[legalspeed]

4-1, less weight.

How about 4-2-1-2-4?

[wastedincome420]

Hey Dan......
Well since YOU have the "Hook Up" for part from LP, you gonna get me 4 new cans?? Honestly I'm gonna see what LP carries for cans and see if you get get me a good deal