Exhaust for YZF 1000
S. Sancewich
I own a 97' YZF 1000 and have a question pertaining to the exhaust. Can
I put a full system on the bike without sacrificing performance? I have
spoken to some dealers and they say to only put on a slip-on. This because
the bike an exhaust valve in the headers. The exhaust valve is said to
regulate the exhaust flow and increase performance. Does anyone have any
experience with a full system on the YZF? Any thoughts about this would be
helpful, since I have heard varying opinions on this question. Can I
expect a substanstial increase in performance from a slip-on and retting?
Daytona12
>I own a 97' YZF 1000 and have a question pertaining to the exhaust. Can
>I put a full system on the bike without sacrificing performance? I have
>spoken to some dealers and they say to only put on a slip-on. This
>because the bike an exhaust valve in the headers.
There are those who will swear by the EXUP valve and a race can and those who
swear AT the EXUP valve and run full systems...
I just got rid of my EXUP and Micron race can set up in favor of a full system.
The EXUP and Micron (or any other slip on) is a no brainer....no jetting
required at all, just richen up the idle mixture a very small amount. No big
difference in power, maybe 3-4 hp peak and you get a better sound for your
efforts. The main cork in the system is the EXUP valve for all out flow.
Yes, the EXUP helps at low rpm but realistically, how much time do you spend
below 3500 rpm? The difference isn't huge down there anyway. However, after
3500-4000 rpm the full system on a bike that is jetted correctly will produce
much better power throughout and you will be cutting off a lot of weight too.
Again, good carb set up is the key. You can't just slap in a jet kit and
expect it to be perfect. It's going to take some trial and error to get it
optimized. Have fun!
-
Jim
Dayt...@aol.com
http://members.aol.com/daytona12/daytona12.html
***********************************************************
1997 Yamaha YZF1000R "Thunderace"
1995 Triumph Dayona 1200 "Bumblebee" 4 sale!!
***********************************************************
* EXUP Brotherhood * AMA *
* Metro Triumph Riders of Michigan *
ey
I just heard the same thing this weekend that due to the EXUP valve train
it's slip on's only.
EY
S. Sancewich wrote in message ...
> I own a 97' YZF 1000 and have a question pertaining to the exhaust. Can
>I put a full system on the bike without sacrificing performance? I have
>spoken to some dealers and they say to only put on a slip-on. This because
S. Sancewich
Any recommedations for a slip-on? Do you need to re-jet?
Daytona12
>I just heard the same thing this weekend that due to the EXUP valve train
>it's slip on's only.
First of all, the EXUP valve has nothing to do with the valve train of the
bike. The EXUP valve is a metal butterly in the collector section which
remains mostly closed during lower rpm use and opens gradually as determined by
the throttle position sensor. This butterfly also is a restriction in the
exhaust gas flow even when it's wide open. The power curve on a stock YZF
stops climbing at 10,000....due to the EXUP valve being in the way. Even
without rejetting, a full system will allow the bike to keep making more power
all the way to 11,300 or so. A properly designed full system for the YZF1000
(Hindle or Indigo Sport) suffers NO loss of power at lower rpm with a properly
jetted bike. Again, some poorly designed systems in the past for some EXUP
equipped bikes may have been a problem but it's by no means a problem on the
YZF1000.
Gizmo
A friend of mine offered me a 'Sorpion' system (full one) for my own YZF1000
(I bought the new bike from him) this system was on his bike but has since
sold the bike, he claims that the system produced "7Hp more at the top end
and 10 in the midrange with a weight saving of 15Kg".
This all sounded to good to be true, but, then thinking to myself about the
EXUP and throttle positioner, I asked him about what happens to these
items?, his response was, "they are removed from the bike" (remove
EXUP=weight saving).
The price was very fair, ½ new price (AUS$700) but my decision was to fit a
new 'Staintune' slip-on (looks good, polished S/S) so as to avoid all the
hassles of removing gear from the bike and getting it rejetted as well.
The Staintune muffler has a restristor fitted (at the outlet) that can be
removed by undoing a 10mm bolt & using a slide hammer (tight sealing fit),
penalty of removing the restrictor is IMHO "excessive noise" for my ears
anyway, and you tend to use about 1000-2000rpm extra above normal
gearchange point just so you can hear the lovely exhaust note (I am talking
about city riding here, different for the bush). The muffled bark with the
restrictor fitted is still quite enjoyable but attracts less attention from
the constabulary.
Pete (Current Toy: 97' YZF1000RK)
Previous toys, 90S, 100LT2, CR125, YZ125D
K250, T500, CB750K,RD400 , XJ750RH, XS1100LH
XJ750RJ, CB900F2, Pepsi GAG, FJ1100, FZR1000D.
ey wrote in message <34f48...@news3.paonline.com>...
>I just heard the same thing this weekend that due to the EXUP valve train
>it's slip on's only.
>
S. Sancewich
Who do you contact to get these slip-ons? What are more of your
thoughts on this EXUP valve, because I hear from other sources that
removing it will decrease performance even with a full system? Besides
what do you lose, p a pound by eliminating the E Where do you ride
your bike now? Commuting? Back road burning? My YZF rips and it
completely stock, but I can always use some advice on mods. XUP?