Okay, this is weird - I have a MOTORCYCLE TECHNICAL QUESTION

 


I have a 1999 SV650 (yes, it rides like a truck compared to the Duc) and
am due for a fork rebuild.  I am considering:  slightly stiffer springs
and the Race Tech Cartridge Emulator kit.  These supposedly make the
crappy damping rod forks behave like cartridge forks - though only on
the rebound - compression damping is still apparently a function of
fork oil weight.

Anybody here have experience with these puppies?

Thanks in advance.

- Michael

PS this is a spam trap address, reply in the group.

 

wrote:

Michael, I have a great deal of experience with the Race Tech
cartridge emulatotors, having had them installed on two EX500 club
race motorcycles, and also on two Ducati 750SS club racing bikes.
They work terrifically when set up with the proper rate springs and
proper spring preload and the correct weight oil for your application.

The forks are both more responsive in that they absorb more small
bumps and ripples, while being less likely to bottom under extreme
braking or when you hit larger bumps.  They are also less likely to
pack up and chatter in hard corner carving where there are multiple
ripples and bumps in the corner itself.

I'll note that in none of these cases did I actually set the forks up
myself; I had a suspension tuner set them up for my weight and lap
times at the various tracks where I was racing.  I can highly
recommend Max McAllister and Traxxion Dynamics, although I believe
that he (they) now have his (own) cartridge emulator that competes
with Race Tech.

Hope this helps!
--

Tim Morrow,
Herndon, VA

 

Tim M. wrote:


Yes, thanks.  Next payday... ;-)

 

wrote:


Wrong. The emulators blow off excess pressure on the *compression
stroke*.

This allows you to experiment with heavier weight fork oils to control
the rebound stroke, because you won't have as much problem with fixed
orifice area limiting the oil flow.

Go to the Race Tech web site and read up on it, or read Kevin
Cameron's book on sportbike technology. You can search the pages of
the book on Google Books.

 



In case none of the usual professional bloviators knows it, the
problem with *unvalved* damper rod forks is that the amount of
compression damping and the amount of rebound damping are *exactly*
the same going either way.

But you don't *need* equal amounts of damping on compression and
rebound,
because you have the fork spring to resist compression.

You only need about 25~30% as much compression damping as rebound
damping.

So the *infinitely adjustable* emulator allows you to fine tune
compression damping to avoid harshness as you ride over sharp-edged
bumps or frost heaves.

Then you can change to a heavier weight oil to adjust the rebound
damping and readjust the emulator to blow off earlier in the
compression stroke.

My early model GSXR-750 has Suzuki's positive damping force (PDF)
valves that have four discrete positions of compression damping
adjustment.

The original intent of PDF was to allow adjustment of fork dive under
heavy braking, but they work the same way as Race Tech's cartridge
emulators.

However, the *real* cartridge fork on my FZR does work better over the
frost heaves on the Angeles Crest Highway.