4 in 1 or 4 in 2 exhaust

  • floridamba
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Re: 4 in 1 or 4 in 2 exhaust

08 Dec 2006 12:21
#98282
you will go deaf faster without the megaphone

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  • martijn
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Re: 4 in 1 or 4 in 2 exhaust

08 Dec 2006 12:30
#98285
Problem is that when it's to loud pulling hard at traffic lights it will attend some cops.... and the do also have fast bikes.....

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  • racer54
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Re: 4 in 1 or 4 in 2 exhaust

06 Mar 2011 12:46
#435565
Ever look at a pro-stock motorcycle lately? Most if not all of the inline bikes use basically a straight pipe instead of a megaphone. Not up on the science of this but they say it doesn't really make any difference between straight pipe and megaphone. Any of you scientist out there able to explain this?
1980 LTD (changed over the years), 1979 LTD (being rebuilt), 1977 KZ turbo and various KZ's in various states of build. KLX110

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  • gane
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Re: 4 in 1 or 4 in 2 exhaust

06 Mar 2011 14:47
#435640
Couple assides, 1, 4-2's regardless of being staggered generally collect side by side....thus render greater center ground clearance so +1, 2 mufflers, -1..."Jardine" cans were light guage & few have stood the test of time...& in MHOP are only slightly better looking than "weed burners". 4-1's...Huge collectors....Look at any/all & check for "flattened" pipes. Sidewinders.... Loss of @ 30% r/h turn clearance..& require mods to clear brake pedal... your' call G
[img][/img] 1977 KZ1000A1

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  • Nebr_Rex
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Re: 4 in 1 or 4 in 2 exhaust

06 Mar 2011 19:35
#435739
The Milkman wrote:
You could probably get as many opinions as there are people on the board. I'll be the first to weigh in I guess. Most of the enthusiasts here seem to prefer a 4 into 1 over the stock exhaust because it gives better scavenging therefore giving more power.
Personally, I prefer my 4 into 2 Jardin system because of the way it's made. Cylinder #1's pipe crosses over so it connects with #4 and goes out the right side, while #2 and #3 connect and go out the left side. This also gives an even pulsing of the exhaust so it scavenges better too.
I guess I just like the looks of the dual exhaust better.
Hope this helps,
Les

Just like the KZ650sr,one of my sr's has a 750,24mm Mikunis,pods and had the stock sr pipes.
Switched to a Mac 4/1,started changing jetting and ended up with what I started out with the stock pipes.
I also have some nos Jardine head pipes,did they quit making pipes for the KZs?
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


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  • kzr750r1
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Re: 4 in 1 or 4 in 2 exhaust

06 Mar 2011 19:51
#435743
Remus had a 4-2-1 for the ZR motors but it looks like they pulled Kawi all together from their line.

Larry and Jeff have points about proper design, your trying to have a proper wave form.

This is one of the huge limiting factors for my build with the ZR750 motor. The Kerker has a HUGE collector and the header pipes are probably really too large as well.

It works but there a limits to it working better.

One of these days I'm going to build a 4-2-1. Mainly so I can design around not taking my pipe off for an oil/filter change. Better state of tune is a plus but almost secondary.
KZ750R1 + 1991 ZR750 = KZR750R1
Better to be shot out of a cannon then squeezed through a tube. - HST

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  • martin_csr
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Re: -

07 Mar 2011 08:08 - 11 Feb 2013 18:11
#435842
-
1981 KZ650 Competition Sports and Road
Last edit: 11 Feb 2013 18:11 by martin_csr.

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  • Jack
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Re: 4 in 1 or 4 in 2 exhaust

07 Mar 2011 14:28
#435951
racer54 wrote:
Ever look at a pro-stock motorcycle lately? Most if not all of the inline bikes use basically a straight pipe instead of a megaphone. Not up on the science of this but they say it doesn't really make any difference between straight pipe and megaphone. Any of you scientist out there able to explain this?

Certainly no scientist but somebody way smarter than me told me a straight pipe will work with 2 valve motors, 4 valves like megs -that would help explain the PSM's or ProMod's with no megs. I'll let you know my findings when the track opens, putting a straight pipe on my Murray,although my reason is more for clearance than performance.
79 KZ 1075 MKll
79 KZ 1500 MKll dragbike
Gone but not forgotten:
3 X 73 Z1's
1 X 74 Z1A
1 X 75 Z1B

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  • wireman
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Re: 4 in 1 or 4 in 2 exhaust

07 Mar 2011 16:16
#435982
so was yosh that far ahead of the game in the 70s then? B)
posting from deep under a non-descript barn in an undisclosed location southwest of Omaha.

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  • nads.com
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Re: 4 in 1 or 4 in 2 exhaust

07 Mar 2011 16:44 - 07 Mar 2011 16:47
#435983
Jeff.Saunders wrote:
Others can probably explain this better than I can, but the collector size contributes significantly to the engines ability to scavenge effectively. Backpressure in the exhaust system is crucial to good performance at lower RPM - that's why a totally open exhaust system will usually feel very tame at lower RPM.[/quote

I had a 4 to 2 straight pipes on factory head pipes and man the low and mid torque was through the roof (felt like I was onboard a REAL bike! All that went out the window when I pulled the baffles my dad made for it.

But the top end came alive!
Put the baffles back in and took them out within 5 miles (no top end pull anymore like before.

The baffles were made exactly to the stock as far as diameter and holes.

I went to attaching car pipe onto the head pipes and then I got a better bottom end and top both, the bottom end still didn't come even close to the old set up.

Want a good broad powerband with stump pulling low end the tighter pipes is key.

Engines run "loose" with wide open pipes, most times it's so mushy you won't like it at all.

And that's my 50c

coyote in the cattle heard! :woohoo:
Last edit: 07 Mar 2011 16:47 by nads.com.

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Re: 4 in 1 or 4 in 2 exhaust

07 Mar 2011 16:48
#435984
nads.com wrote:
Jeff.Saunders wrote:
Others can probably explain this better than I can, but the collector size contributes significantly to the engines ability to scavenge effectively. Backpressure in the exhaust system is crucial to good performance at lower RPM - that's why a totally open exhaust system will usually feel very tame at lower RPM.

I had a 4 to 2 straight pipes on factory head pipes and man the low and mid torque was through the roof (felt like I was onboard a REAL bike! All that went out the window when I pulled the baffles my dad made for it.

But the top end came alive!
Put the baffles back in and took them out within 5 miles (no top end pull anymore like before.

The baffles were made exactly to the stock as far as diameter and holes.

I went to attaching car pipe onto the head pipes and then I got a better bottom end and top both, the bottom end still didn't come even close to the old set up.

Want a good broad powerband with stump pulling low end the tighter pipes is key.

Engines run "loose" with wide open pipes, most times it's so mushy you won't like it at all.

And that's my 50c

coyote in the cattle heard! :woohoo:

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  • gd4now
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Re: 4 in 1 or 4 in 2 exhaust

07 Mar 2011 16:57 - 07 Mar 2011 18:00
#435988
This attached file explains the exhaust process and how and what some of the things are that go into header design. I found this on the internet, so am in no attempt trying take credit for its creation. But the location I found it did not give an indication as to who did create it. I just found it to be a pretty quick read that explained the process.

Attachment understanding_exhaust.txt not found

1977 KZ650 B1
Pods and Denco header

OLD KAW OWNERS SMILE ALOT

Attachments:

Last edit: 07 Mar 2011 18:00 by gd4now.

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