Page 1 of 2 1 2 LastLast
Results 1 to 10 of 11
  1. #1
    mrbtd's Avatar
    Join Date
    Jul 2005
    Location
    Lindenhurst, Illinois, United States
    Posts
    4,309
    +1
    2

    Time to work on the bottom of the ski

    Ski is a 2001 12r - 145lb Comp, Open FA's,Rejet,VF2 reeds,05 Pump w/stock 14/20 (verified 14/20) Running a Jims FF plate and Shortened R&D tabs.

    I know to clean up all the nicks/gouges with MarineTex.

    Verified the grate/pump shoe is not below the flat spot in front of the intake grate (a nickel).

    From 3" in front of the Intake grate back to the middle bottom of the plate I get a 1.287" measurement and there is no bouncing. Tabs are shimmed down with .50 washers (all 8 bolts).

    Anything else to look at under there ?

    I am @ 68.5-70.2 (on the seat) depending on fuel and conditions - RPM's = 7110 in the heat.

    Ski accelerates hard, mid range is very crisp, plugs are good, PV are good.


  2. #2
    Brian Thomas's Avatar
    Join Date
    Apr 2007
    Location
    East TN
    Posts
    246
    +1
    10
    Quote Originally Posted by mrbtd View Post
    Ski is a 2001 12r - 145lb Comp, Open FA's,Rejet,VF2 reeds,05 Pump w/stock 14/20 (verified 14/20) Running a Jims FF plate and Shortened R&D tabs.

    I know to clean up all the nicks/gouges with MarineTex.

    Verified the grate/pump shoe is not below the flat spot in front of the intake grate (a nickel).

    From 3" in front of the Intake grate back to the middle bottom of the plate I get a 1.287" measurement and there is no bouncing. Tabs are shimmed down with .50 washers (all 8 bolts).

    Anything else to look at under there ?

    I am @ 68.5-70.2 (on the seat) depending on fuel and conditions - RPM's = 7110 in the heat.

    Ski accelerates hard, mid range is very crisp, plugs are good, PV are good.
    Which intake grate are you running? I have very similar setup but with stock reeds and my rpm in the heat is actual about 30-40rpm less but the speed is 72.5-73.5mph(90 degree temps) This with box stock 14/20 DF thru 85mm nozzle, jims FF plate, 800 grate, and stock unshimmed tabs. -BT

  3. #3
    mrbtd's Avatar
    Join Date
    Jul 2005
    Location
    Lindenhurst, Illinois, United States
    Posts
    4,309
    +1
    2
    Its a 1200 grate and 87 nozzle. I suspect that is 1-1.5mph diff and 40-70 rpm's.

    I am ok with this but want to be sure the ski is "right".

  4. #4
    Brian Thomas's Avatar
    Join Date
    Apr 2007
    Location
    East TN
    Posts
    246
    +1
    10
    Quote Originally Posted by mrbtd View Post
    Its a 1200 grate and 87 nozzle. I suspect that is 1-1.5mph diff and 40-70 rpm's.

    I am ok with this but want to be sure the ski is "right".
    Cool, yea, mine measures out .920", again tabs with no washers. -BT

  5. #5
    Quote Originally Posted by mrbtd View Post
    Ski is a 2001 12r - 145lb Comp, Open FA's,Rejet,VF2 reeds,05 Pump w/stock 14/20 (verified 14/20) Running a Jims FF plate and Shortened R&D tabs.

    I know to clean up all the nicks/gouges with MarineTex.

    Verified the grate/pump shoe is not below the flat spot in front of the intake grate (a nickel).

    From 3" in front of the Intake grate back to the middle bottom of the plate I get a 1.287" measurement and there is no bouncing. Tabs are shimmed down with .50 washers (all 8 bolts).

    Anything else to look at under there ?

    I am @ 68.5-70.2 (on the seat) depending on fuel and conditions - RPM's = 7110 in the heat.

    Ski accelerates hard, mid range is very crisp, plugs are good, PV are good.
    Am I correct in assuming you dont have the 2" pump extention? The washers under the tabs will shave a little speed but if your happy with the handling I would leave them.

  6. #6
    mrbtd's Avatar
    Join Date
    Jul 2005
    Location
    Lindenhurst, Illinois, United States
    Posts
    4,309
    +1
    2
    Thanks for the input...

    No 2" extension. I am thinkiking I will remove the washers from the tabs and lessen the angle on the plate. Figure its a trade off either way and its free to try.

    I need to fill some holes also.

    Any other ideas ?

  7. #7
    Like a chimp with a ball-peen hammer smackwave's Avatar
    Join Date
    Dec 2005
    Location
    Annapolis, MD
    Posts
    621
    +1
    22
    It sounds like you're on the right track. Reduce the plate angle to close to .950", swap in an 800 grate, remove the shims from the tabs, plug all bolt holes, change to an 85mm nozzle and you're close to or over 73 on the buzzer in smooth water. If you haven't already, remove the bilge siphon from the pump nozzle for a bit more RPMs and speed, then work on truing your hull. Other things to consider: Advent CDI or 3 degree keyway, hole shot kit, 2" pump extension, removing trim tabs altogether. That should get you close to 75 and possibly in need of a repitch.

  8. #8
    Brian Thomas's Avatar
    Join Date
    Apr 2007
    Location
    East TN
    Posts
    246
    +1
    10
    Quote Originally Posted by smackwave View Post
    It sounds like you're on the right track. Reduce the plate angle to close to .950", swap in an 800 grate, remove the shims from the tabs, plug all bolt holes, change to an 85mm nozzle and you're close to or over 73 on the buzzer in smooth water. If you haven't already, remove the bilge siphon from the pump nozzle for a bit more RPMs and speed, then work on truing your hull. Other things to consider: Advent CDI or 3 degree keyway, hole shot kit, 2" pump extension, removing trim tabs altogether. That should get you close to 75 and possibly in need of a repitch.
    May reopen a can of worms..........but, IS there a speed GAIN with the 2" pump extension?

  9. #9
    2000 GPRXP 4tec shooter98xpl's Avatar
    Join Date
    Dec 2005
    Location
    Charleston SC
    Posts
    2,717
    +1
    3
    I have been wondering the same thing Brian.
    Remember the old 95xp800 with the 2 inch pump extension. That thing use to porpoise bad at top speed. Then the 96xp800 came out and the porpoising was gone. It didn't have the 2 inch pump extension.
    I have been wondering the same thing on the GPR's. But have not had time to swap out the 2 inch extension to see if it made a difference. I know everyone says its faster, but then I've heard a lot of bullshit being spilled out in the past.
    SHOOTER

  10. #10
    just GOT TO DO IT! great lakes gpr 1200's Avatar
    Join Date
    May 2006
    Location
    muskegon michigan
    Posts
    798
    just food for thought:
    I did back to back testing on removing the washer behind the impeller. with the washer gone so the impeller set back, I lost 1.4 mph at 74.2 . pulled it apart, on the ramp, put the washer back, and got 75.6 mph on the next runs.
    This tell me the point of balance was changed? I am not sure. but I do not want a 2" extention to make my pump longer? Becuase I thing that would change my skis balance.
    Now I run the old pump in my ski too..
    This Is just what I rean across when playing with my pump.

Page 1 of 2 1 2 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 5
    Last Post: 06-26-2016, 04:03 PM
  2. How hard is it to work on the new 2012 RXP or RXT ?
    By Makesumwake in forum Sea Doo Open Discussion
    Replies: 2
    Last Post: 10-02-2013, 06:02 AM
  3. Went to work on the ski, hit a snag right off the bat...
    By burtonrider10022 in forum Polaris Open Discussion
    Replies: 3
    Last Post: 07-10-2013, 05:53 PM
  4. Time to get on the water, Problem with seal.
    By xBigDaddyx117 in forum 4-Tec Performance
    Replies: 8
    Last Post: 04-01-2010, 06:09 PM
  5. Riding Hours vs Working on the Ski Hours
    By jack in forum 4-Tec Performance
    Replies: 12
    Last Post: 11-27-2005, 03:39 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •