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Discussion Starter #1
1. what is the difference between 4-1 headers and 4-2-1 headers besides that the 4-2-1 has an extra step in there?
2. yosh has a duplex system what is and what does the duplez system do?
and yes it is a proven fact that i am the village idiot lol

thanks in advance


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'99 gsxr 750 with some nice scratches on the left side oops lol
 

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4-1 is a little seen pipe design today.

quick power lesson, most bolt-on parts move hp. an exhaust is one such part (though some improve just about everywhere just because of better materiels).

a 4-1 (where all 4 header pipes join into the collector at the same time) is designed for top-end power only and generally hurts mid-range.

a 4-2-1 (where the header pipes mate up into pairs, then into the collector) is designed to keep some mid-range compared to the 4-1. these are way more popular. most bikes have this design stock and most aftermarket headers are pretty close in their bends to the stock pipes.

as for yosh's duplex. i haven't seen one in a while, though i think they still make them for gsx-r's.

the last one i saw up close, was a 4-1 pipe, with two cannisters each can was connected to two pipes, kind of like a cross-over pipe on a mustang, but smaller and just after the first bend in the headers, near the exhaust ports.

the idea is when exhaust velocity is low, it acts like a 4-2-1 pipe, with exhaust hases filling the cans (harley also uses this kinda idea to get some power on the sportster motors, though i don't think the exhaust ever flows fast enough for the latter effect). when exhaust flow is high, it by-passes the duplex cans and acts like the 4-1.

yosh used to make a lot of power with these pipes (back in the day). i don't know for sure if they're still using them even (for newer bikes).


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Tony

the views and opinions expressed by tony (cbrf2boy) are the ramblings of a total idiot. sbw.com, it's administrators, moderators, and members don't necessarily agree with and are not responsible for anything this idiot has to say.

for more ramblings try http://geocities.com/cbrf2boy

[This message has been edited by cbrf2boy (edited July 27, 2000).]
 

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Discussion Starter #3
hey thanks for the info.. now im off to see what kind of system i wanna buy... too many choices these days
thanks again for the info

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'99 gsxr 750 with some nice scratches on the left side oops lol
 

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my suggestion is m4.

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Tony

the views and opinions expressed by tony (cbrf2boy) are the ramblings of a total idiot. sbw.com, it's administrators, moderators, and members don't necessarily agree with and are not responsible for anything this idiot has to say.

for more ramblings try http://geocities.com/cbrf2boy
 

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Okie, here is what ya wanna do, go and get an Akrapovic. Yeah they are like $1000 but it only weighs 9 lbs. and a full Yosh titanium duplex is like $1500 and it weighs 7 lbs. It isnt worth the extra $500 for 2 lbs. Plus not to many have the Akrapovic. Later.

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Discussion Starter #7
i wish i could afford the akro. but i will have about 5-700 to spend since i have to buy that damned $329 power commander but im deciding between m4, yosh, D&D, and micorn but i dont know much about micron

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'99 gsxr 750 with some nice scratches on the left side oops lol
 

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Heh whats up. About your Hp desire for your nice 99 gixxer with the cosmetic blemishes well I have done a tonn or research and if you remember last year in Sport bike rider they tested 12 systems with that exact system the 99 gixxer and the power commander
Hindle and Muzzy netted the most power gains
I went with Hindle and found after alot of testing that the Power commander makes alot of difference but it worked better with it set on the stock settings not the race pipe settings. This is a much more agressive setting than the bikes own computer and it works damn well. In a few days aug 4,5,6 I will be able to give you detailled figures on HP and Tourque. If you have any questions feel free to email me I might be able to save you alot of money and time cause in Canada your dollar goes alot further
[email protected]

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If you are not on a gixxer what are you waiting for??
 
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