2 Cycle Setup on a Pipe

[Brian Young]

Maybe Dean can discuss this too.

I can tell you on my 1.45s I reduced the fuel pressure
to cure a midrange richness. I know others who did the
same. By doing this I was able to achieve a great
running engine. I may have been skinning the cat the
other way. 


--- randy10926 at comcast.net wrote:
> Man that describe my 145.  It is my second one and
> still low mileage, but mid range is a problem.
> 
> Randy
> > You might still wish to shorten the pipe, be on
> the lookout for mid-throttle 
> > hysteresis. If you are not flying at mid throttle
> for most of your level lines, 
> > you might not be looking for this. The symptom is
> an inconsistent power level 
> > when you pull back or throttle up to the same
> middle-stick position. 
> > Hope this helps,
> > 	Dean
> > 
> > -----Original Message-----
> > From: Brian Young [mailto:b4598070 at yahoo.com]
> > Sent: Wednesday, March 31, 2004 4:11 PM
> > To: discussion at nsrca.org
> > Subject: RE: 2 Cycle Setup on a Pipe
> > 
> > 
> > ;)
> > 
> > I tried this over the past weekend, Ive seen you
> > mention this before. It didnt richen at all. 
> > 
> > --- Dean Pappas <d.pappas at kodeos.com> wrote:
> > > Reasonable question!
> > > The box width, or 5 seconds, or 50,000 miles:
> > > whichever comes first.
> > > Did it not richen at all, or just not enough to
> > > burble?
> > > I take it that you got out and flew during the
> last
> > > hour.
> > > Dean
> > > 
> > > -----Original Message-----
> > > From: Brian Young [mailto:b4598070 at yahoo.com]
> > > Sent: Wednesday, March 31, 2004 2:37 PM
> > > To: discussion at nsrca.org
> > > Subject: RE: 2 Cycle Setup on a Pipe
> > > 
> > > 
> > > Ok, how long is a long shallow dive at full
> > > throttle.
> > > 10 seconds, 30, ......
> > > 
> > > I did this w/ my 26.5" setup for about 5-10
> seconds
> > > and no burble.
> > > 
> > > --- Dean Pappas <d.pappas at kodeos.com> wrote:
> > > > Hello Randy and Bob,
> > > > The pipe length from piston face (the plane of
> the
> > > > exhaust port) to the reflector baffle is
> > > > approximately proportional to the exhaust
> timing.
> > > > The suggestion to start by shortening the 160
> pipe
> > > > by 0.5" to 1"  Dave gave you is based on this,
> and
> > > > his running of both engines. You do not want
> to
> > > > shortenn for maximum ground RPM, you want to
> start
> > > > long, and fly. After verifying the "correct"
> > > needle
> > > > setting, try a long 5-degree full throttle
> dive.
> > > If
> > > > the engine gurgles rich, shorten a bit, and
> try
> > > > again. When the engine no longer richens, in
> the 5
> > > > degree dive, stop. Any further shortening
> 
> > > sacrifices
> > > > flexible running characteristics for only the
> > > > tiniest real horsepower inprovement. 
> > > > Dean
> > > > 
> > > > -----Original Message-----
> > > > From: Brian Young [mailto:b4598070 at yahoo.com]
> > > > Sent: Wednesday, March 31, 2004 1:55 PM
> > > > To: discussion at nsrca.org
> > > > Subject: Re: 2 Cycle Setup on a Pipe
> > > > 
> > > > 
> > > > Randy Im at 26.5 from the exhaust flange right
> > > now.
> > > > The 1.60 runs fine at this length, but im only
> > > > getting
> > > > 7700 rpm on a 17x12 which I think is low.
> > > > 
> > > > I had suggestions of 27 inches for a target
> from
> > > the
> > > > 1.45, less about .5"-1" for the 1.60. But on
> Ed
> > > > Hartleys website I notice someone running as
> long
> > > as
> > > > 30". 
> > > > 
> > > > FWIW the exhaust timing I measured on the 1.60
> is
> > > > 140
> > > > degrees, and on the 1.45 is 147.
> > > > 
> > > > --- randy10926 at comcast.net wrote:
> > > > > Does anyone else have the ppe lenght for the
> > > Webra
> > > > > 160?  Hos much change would be need to
> replace
> > > my
> > > > > 145 with a 160.
> > > > > 
> > > > > Randy
> 
> > > > > > Don't know, Randy.  I don't know the
> timing of
> > > > the
> > > > > Webra 160 and no one has
> > > > > > let me borrow one.  I own the Webra 145,
> > > OS140,
> > > > > Mintor 170 and regularly use
> > > > > > these in testing.
> > > > > > --Lance
> > > > > > 
> > > > > > ----- Original Message ----- 
> > > > > > From: <randy10926 at comcast.net>
> > > > > > To: <discussion at nsrca.org>
> > > > > > Sent: Tuesday, March 30, 2004 3:17 PM
> > > > > > Subject: Re: 2 Cycle Setup on a Pipe
> > > > > > 
> > > > > > 
> > > > > > > Is the pipe length for the Webra 160 the
> > > same
> > > > as
> > > > > for the Webra 145?
> > > > > > >
> > > > > > > Randy
> > > > > > > > Ditch the MC carb during testing and
> put a
> > > > > regular 1.45 carb on it.  The
> > > > > > > > bench mount it.  I have been testing
> > > > AeroSlave
> > > > > carbon pipes for a year
> > > > > > now
> > > > > > > > and have a great setup for quickly
> getting
> > > > > tuning length and rpms.  I
> > > > > > have a
> > > > > > > > "trombone" made from two pieces of
> silicon
> > > > > coupler with a short length
> > > > > > of
> 
> > > > > > > > aluminum header pipe in between. By
> > > starting
> > > > > with everything extended to
> > > > > > the
> > > > > > > > extremes and sliding the whole mess
> > > together
> > > > I
> > > > > can watch a tach and take
> > > > > > > > readings real time.  Takes about 5 min
> to
> > > > get
> > > > > the numbers and then setup
> > > > > > the
> > > > > > > > flying lengths.
> > > > > > > > --Lance
> > > > > > > >
> > > > > > > > ----- Original Message ----- 
> > > > > > > > From: "Brian Young"
> <b4598070 at yahoo.com>
> > > > > > > > To: <discussion at nsrca.org>
> > > > > > > > Sent: Monday, March 29, 2004 3:16 PM
> > > > > > > > Subject: 2 Cycle Setup on a Pipe
> > > > > > > >
> > > > > > > >
> > > > > > > > > I have recently been tuning on my
> > > exhaust
> > > > > and have a
> > > > > > > > > basic understanding but want some
> more
> > > > > information.
> > > > > > > > >
> > > > > > > > > I have a Webra 1.60 w/ MC carb and a
> > > Webra
> > > > > pipe w/ a
> > > > > > > > > disk baffle.
> > > > > > > > >
> > > > > > > > > Im gradually shortening this pipe
> setup
> > > > > hoping to hit
> > > > > > >
> 
=== message truncated ===


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