750sx impeller questions
Troy Hoehner
I ride a '93 750sx with the following mods:
sano pad
SXI lanyard switch
rule 1100 bilge
aquavain intake grate
ocean pro "ocean" ride plate
vortex flame arrestor
primer kit
boysen reeds
skat trak 14-17 impeller (installed by previous owner)
I am looking for more bottom end without loosing much top end if thats
possible. I just had .060" milled from the head, but noticed no change?
the compression barely changed 5 psi. (maybe they cut too much in squish
band?) I have been told that I need a 9-17 impeller not the 14-17 ?
What changes will I see if I make this change ? My top speed is not
much better than stock will it go down by changing the impeller ?
Also, Does anyone know what the pitch is for the stock impeller, I
still have it and wonder if it might be a better choice than the 14-17
Skat Trak.
Thanks
Troy Hoehner
simonw
Troy Hoehner <thoe...@texoma.com> wrote:
>I ride a '93 750sx with the following mods:
>sano pad
>SXI lanyard switch
>rule 1100 bilge
>aquavain intake grate
>ocean pro "ocean" ride plate
>vortex flame arrestor
>primer kit
>boysen reeds
>skat trak 14-17 impeller (installed by previous owner)
>
>I am looking for more bottom end without loosing much top end if thats
>possible. <snip>
>much better than stock will it go down by changing the impeller ?
>Also, Does anyone know what the pitch is for the stock impeller, I
>still have it and wonder if it might be a better choice than the 14-17
I would definitely NOT reinstall the stock impeller; it's aluminium.
Virtually any stainless prop (even the wrong pitch) will work better
than the stock aluminium prop.
I've seen the Skat-Trak 9-17 advertised for use in stock and limited
750SX's, according to Jet Express' latest supplement in Splash
magazine. Or for a bit more top-end you could try the 10-18.
I have a Solas in my ski, I'm pretty sure it's a 14-19 and the low end
is quite nice (but could be better). Then again I haven't compared it
against anyone else's 750 so it might be great. But I haven't had
any problems with cavitation at low or high speeds, so chances are
it's pretty close to spot on. I think your best bet is to speak to
both Skat-Trak and Solas, tell them the mods you have and they will be
able to give you a better idea.
If you're so keen on bottom-end, why not try the Swirl props?
Unfortunately you'll lose a bit of top-end. Nothing's free I'm
afraid!
Michael J. Halberstadt
In <318E87...@texoma.com> Troy Hoehner <thoe...@texoma.com>
writes:
>I ride a '93 750sx with the following mods:
>sano pad
>SXI lanyard switch
>rule 1100 bilge
>aquavain intake grate
>ocean pro "ocean" ride plate
>vortex flame arrestor
>primer kit
>boysen reeds
>skat trak 14-17 impeller (installed by previous owner)
>
>I am looking for more bottom end without loosing much top end if thats
change?
>the compression barely changed 5 psi. (maybe they cut too much in
squish
>band?) I have been told that I need a 9-17 impeller not the 14-17 ?
>What changes will I see if I make this change ? My top speed is not
>
>Also, Does anyone know what the pitch is for the stock impeller, I
>still have it and wonder if it might be a better choice than the 14-17
>
>Thanks
>Troy Hoehner
I don't know what the stock prop is and can't find it in the manual.
On my 94 SX which is basically like yours without the head mod I have
run a 9-17 and 10-18 Skat Trak (my wife has a 750SS) so I tried both on
each ski. Both are much better than stock. AS you would guess the 9-17
comes out of the hole better than the 10-18 but the 10-18 has a little
more top end. What I really notice with the 10-18 on the SX is the
speed at 1/2 to 3/4 throttle is much more than the stock and it seems
to hold that speed easier. I'm talking feel. I don't have a radar set
up. I ended up with the 10-18 on the SX and the 9-17 on the SS. I'd
prefer the 9-17 on both but don't want to fork out another $300. By
the way the 9-17 and a scope grate transformed my wifes 750 SS.
Mike, San Diego (Vista really)
Jim Cuviello
Troy,
The stock 750sx came with a 14/19 alum.. A Skat-Trak 9/17 or Solas 13/18
is the prop you need. I can say you will notice considerable difference
most likely all around. I don't want to say exactly what difference
because I am not really sure what prop you have on your ski. Skat did
make some race props that had a three degree difference for the 750s and
they do make props for the 550s that are 14/17 but they will not fit on
the 750s. Keep in mind that if you put an exhaust system on that you
might want to consider a different prop. I say might because I had a
750sx that I ran with a Solas 13/18 and it ran great. I lost a little on
the top but the bottom was strong and power throughout the entire power
band was smooth. I tried several other props on the same ski but it is a
long story.
Who did you head? You should have been able to specify what you wanted
your compression to end up with.
Jim Cuviello
Water Ways
Performance Watercraft
Ocean City - Maryland
1-800-886-3322
http://www.water-ways.com
GER
I suggest using the Skat 9-17 on your boat because it doesn't have a lot
of mods. This smaller prop will be great out of the hole and will likely
put you in good shape for a hole shot. I use this prop on my Limited race
boat and often get the hole-shot. I also use a Factory Limited pipe, Jet
Dynamics top loader + ride plate, reed stuffers, a bit more compression,
and a few internal tricks. Good Luck.
GER
Rick Fisher
In article <318E87...@texoma.com>,
Troy Hoehner <thoe...@texoma.com> wrote:
>I ride a '93 750sx with the following mods:
>sano pad
>SXI lanyard switch
>rule 1100 bilge
>aquavain intake grate
>ocean pro "ocean" ride plate
>vortex flame arrestor
>primer kit
>boysen reeds
>skat trak 14-17 impeller (installed by previous owner)
>
>I am looking for more bottom end without loosing much top end if thats
>possible. I just had .060" milled from the head, but noticed no change?
>the compression barely changed 5 psi. (maybe they cut too much in squish
>band?) I have been told that I need a 9-17 impeller not the 14-17 ?
>What changes will I see if I make this change ? My top speed is not
>much better than stock will it go down by changing the impeller ?
>
>Also, Does anyone know what the pitch is for the stock impeller, I
>still have it and wonder if it might be a better choice than the 14-17
>Skat Trak.
>
>Thanks
>Troy Hoehner
Troy
I have a 1992 750SX. The prop (14-17) is just an older numbering system. It
is probably 99.9% the same bend as the new one. However, the 17 pitch is
better for stock motors and conducive to low end power. A 19 pitch would
increase top end but decrease low end power. It would take longer to get to
the new faster top speed. It's a trade off. However, you can offset the
loses by boosting engine power in the area your hurting. An example is
putting in reed stuffers (which accelerate the fuel charge and thus
increases acceleration) when you install a taller (higher number) prop. You
lose a little acceleration to the prop but make it up with the reed
stuffers. I could go on and on but I wont.
Something is very suscpicious about the mill job. 60 thou should have
boosted psi more than 5psi. However, I would not have shaved the head
alone. I would have had the head RE-WORKED that means reashaping the head
after the milling. i ahve just such a head and it works fine. If you need
another head (now) buy a stock one from a 750 SXi or 750ZXi. The SXi will
will keep you on pump gas and the ZXi head MIGHT make you run race gas
$$$$. try to remember that Kawasaki spent many years designing the engines
and they must know something about it. I am buying a factory head instead
of aftermarket, even though it costs more.