Results 1 to 8 of 8
  1. #1

    Join Date
    Nov 2009
    Location
    NC
    Posts
    782
    +1
    29

    Can you stop a GP760 from porpoising?

    Installed a Pro-Tec intake grate and Riva ride plate (shimmed with 2 washers in back) on my '97 GP760 in hopes that the porpoising would stop. Had one smooth run on virtually "glass" water. Turned around to come back and the porpoising returned. What else can I do? Am I better off buying a 2001 GP800R or do they porpoise too?


  2. #2
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    Moved this to the old school section there are quite a few threads in here regarding porpoising on this ski, it is the same platform as the GP1200.

  3. #3
    Dave Sharp dav_dman's Avatar
    Join Date
    Aug 2005
    Location
    louisville Ky/so. IN
    Posts
    1,453
    +1
    1
    which riva plate..the groovy is garbage..the longer one is good. You need trim tabs..you can make them or have them made..dwgs on here..

  4. #4
    Old Ski Insanity w/rpm500's Avatar
    Join Date
    Aug 2005
    Location
    Crystal River Fl
    Posts
    2,208
    long plate is good!! you'll need approx 1/2 inch stack of washers at the rear along with the requisite longer bolts!! this will help the 760 hull...
    depending on model year's (your 97' and thru mid year 98' ) you'll need those trim tabs also..

    handleing will improve in steps with the hull angle change,thou along with a drop in ultimate speed.. please add your washers in steps ..I have found on my 97 gp760 .44 was ideal ! also remember you have nozzel trim angle capability!
    the 760's seem to require a 'nose in' setup as apposed to the 1200 's nose lifted out setup (shims front), due to weight, hp and pump capabilitys...

    every ski is different so experiment (IMO, shims rear for you ,up to 1/2 inch)

  5. #5
    Budman's Avatar
    Join Date
    Jul 2008
    Location
    Montana
    Posts
    341
    Also make sure your sponsons are in the lowest position.

  6. #6
    Flying Scotsman's Avatar
    Join Date
    May 2006
    Location
    IllINOIS
    Posts
    6,514
    +1
    4
    Turn it into a 1200 and you can set it up to porpouse only at low speed.
    Then you dont go slow so you dont porpouse.
    A gp1200 will porpouse more in stock form because it cant maintain the lift to keep the nose up.
    Once you add a little more power it settles down.
    A 760 will always have a hard time maintaining lift thats why they all shim the rear insted of the front bolts.
    If you want to go fast and cure the porpouse do a swap to moded 97-99 GP1200.

  7. #7
    Old Ski Insanity w/rpm500's Avatar
    Join Date
    Aug 2005
    Location
    Crystal River Fl
    Posts
    2,208
    Quote Originally Posted by Flying Scotsman View Post
    Turn it into a 1200 and you can set it up to porpouse only at low speed.
    Then you dont go slow so you dont porpouse.
    A gp1200 will porpouse more in stock form because it cant maintain the lift to keep the nose up.
    Once you add a little more power it settles down.
    A 760 will always have a hard time maintaining lift thats why they all shim the rear insted of the front bolts.
    If you want to go fast and cure the porpouse do a swap to moded 97-99 GP1200.
    always gunning for those 1200 swaps !!!

    a GP760 is what he has, so the 'NEEDED' set up is shims at the rear..

  8. #8
    Flying Scotsman's Avatar
    Join Date
    May 2006
    Location
    IllINOIS
    Posts
    6,514
    +1
    4
    GP1200
    Thats what I would do if I had a GP760.
    I am sure you guys know what your talking about shiming your ride plates in the rear on the GP760.
    I just put a brand new ride plate on the 97 it was a bitch to get any angle on it.I have it shimed so its the thickness of a piece of paper between the plate and the pump.I could only get 2 washers/shims under the front
    I bought it to test it against a stock plate that was on there and it will be for sale in a couple of weeks if anyone is interested.
    I think this Pro tec plate would work well shimed in the rear on a GP760 it is not looking good for speed on the 97 although it should handle quite well.
    I think you want to go big bore and use one of the top porters so you can make max power.
    Power is whats needed to stop the porpouse.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Can you split the feed from an O2 sensor?
    By tornado34 in forum 4-Tec Performance
    Replies: 0
    Last Post: 04-19-2015, 02:42 AM
  2. Can you stop a GP760 from porpoising?
    By toyterrific in forum Yamaha Open Discussion
    Replies: 0
    Last Post: 05-18-2010, 07:25 AM
  3. can you seperate the top deck from the hull?
    By Mr Bill in forum Yamaha PWC Performance (2-stroke)
    Replies: 9
    Last Post: 07-28-2008, 04:52 AM
  4. What can you tell me from this photo?
    By NZUltra in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 04-27-2008, 10:02 AM
  5. What Can You Do To stop Porpoising 99 gp1200
    By DONALDBUCHANAN in forum Yamaha PWC Performance (2-stroke)
    Replies: 11
    Last Post: 08-03-2007, 07:01 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
  •