Results 1 to 5 of 5
  1. #1
    PWC Newbie
    Join Date
    Aug 2009
    Location
    Sweden
    Posts
    29

    Popoff pressure for 1050 big bore?

    I have rebuilt my Seadoo GSX Limited now with a 1050 kit, 91.89 mm pistons which make a total of 1037cc. The ports have been raised a fair bit, if that matters?

    I'm going to start adjusting the carbs now, and I'm wondering what popoff pressure I should be aiming at? I have Prok's with Outerwears, 95 lows without accpump, 172.5 highs, 2.3 N&S with 95 gram springs.

    According to the popoff chart that should be 20psi of popoff, is that fine or should I change something?

    Will start a new thread when the tuning begins.


  2. #2
    SURFnTURF's Avatar
    Join Date
    May 2007
    Location
    Australia
    Posts
    878
    +1
    11
    IMO your highs are too rich even with the adjusting screws closed.I have a 1050 with white pipe that will rev into the 7200s easily and running 2.0 N/S 167.5s closed 95 lows open 1.5 turns black spring 21 psi pop off.Gets up and goes with rinnaldi reeds,stock head,ignition advanced 2 degrees, off set bores with lightened flywheel and no outer pto.Excellent surf boat.

  3. #3
    PWC Newbie
    Join Date
    Aug 2009
    Location
    Sweden
    Posts
    29
    I have now measured the popoff to about 17 psi, maybe a tad bit higher. Should I try to adjust it to closer to 20 psi, or can I use it as it is?

    It runs quite well now, but not higher than 6400 rpm, regardless of the Rave-springs removed or not. I didn't have a very good spot to run it on, so I couldn't do a proper chop run. Could my large high speed jets together with 2 turns out on the high speed adjusters make it limited to that rpm? I just wanted to make sure that it didn't run lean, and as said before I didn't have a good place to do my tuning.

    Would it be safe to do a short WOT run with the high speed adjusters closed?

  4. #4
    SURFnTURF's Avatar
    Join Date
    May 2007
    Location
    Australia
    Posts
    878
    +1
    11
    Quote Originally Posted by Sandell View Post




    Would it be safe to do a short WOT run with the high speed adjusters closed?
    I would get it at 20-21 as the higher the pop off the crisper the throttle response.But 20-21 is good with after market filters.

    I didn't realise you where at 2 full turns out on the 172.5 jets. YES way too rich this would choke your engine with fuel and hold revs down as you are experiencing. Every time you open the adjuster screws 1 turn you deliver approx 5 more points of fuel so you are about 182.5 on your jets.


    YES CLOSE THEM and watch your revs climb.Still scared ? then turn them in 1 turn and see a difference but a 1050 bore doesnt require much more fuel than a stock bore as you havent increased its revs just displacement.
    But 167.5 closed or if you have to 170 closed as long as you run 95 lows will get your revs back in the 7000s dependant on prop.

  5. #5
    PWC Newbie
    Join Date
    Aug 2009
    Location
    Sweden
    Posts
    29
    Very interesting and many thanks, I will try this tomorrow and update the thread with my results.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. FS - Parts 1200 big bore for 900/1050
    By 1FASTXC in forum Polaris Classifieds
    Replies: 13
    Last Post: 06-09-2016, 10:28 PM
  2. 1050 Big Bore
    By gitrdone in forum 2-Stroke Performance
    Replies: 8
    Last Post: 04-28-2008, 09:22 PM
  3. ? Where to go for best big bore kits ?
    By blasterboy1980 in forum Yamaha PWC Performance (2-stroke)
    Replies: 2
    Last Post: 03-13-2008, 02:49 PM
  4. 1050 big bore
    By stvdrag225 in forum 2-Stroke Performance
    Replies: 7
    Last Post: 09-24-2007, 01:02 PM
  5. Big Bore kit for GP1200R
    By croskel in forum Yamaha PWC Performance (2-stroke)
    Replies: 12
    Last Post: 05-09-2006, 01:58 AM

Posting Permissions

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