Results 1 to 3 of 3
  1. #1
    GPHOTROD's Avatar
    Join Date
    Apr 2006
    Location
    Dearborn Heights, Mich
    Posts
    65

    Still Chasing RMP loss

    I have two 1300s built the same, both have always run the same rpm and the same speed. Now all of a sudden one of them lost 50-60 rpm and about 1 mph.

    Thing I have already checked include.

    I have changed head gasket
    Checked the reeds - OK
    Checked and adjusted power valves - OK
    Tried a different EFI controller - no change
    Pulled pump and checked bearing - OK
    New plugs side gapped and indexed
    Checked Compression - still the same

    Anybody have any ideas?

    2003 1300 GPR 75.9 @ 7090
    Unported and Injected.
    Fercho's Package, and 3 deg key
    Head by Lowell Horning.
    Rossnemos Sonic Boom TB Mod.
    Jims FF Mod Plate & Trim Tabs.
    14/23 Solas DF Frecho Spec from Impros.
    Riva 1200 Grate.


  2. #2
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
    Join Date
    Nov 2005
    Posts
    6,194
    +1
    536
    Check to see if the pump shoes bolts are tight, If any of them have come loose at top speed the pressure will push the shoe down and create drag. Also check the ride plate bolts and trim tabs. Also check the pump shoe seal job make sure no sealer has blown out of the pump shoe. I have seen a few that have blown out at the rear of the shoe between the shoe and transom plate.

  3. #3
    GPHOTROD's Avatar
    Join Date
    Apr 2006
    Location
    Dearborn Heights, Mich
    Posts
    65
    All look good . I'm going to check the jetworks gasket next to make sure it's not leaking, and letting to much water into the water box. Then if I have to the keyway.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Chasing RPM loss
    By AReiter in forum 4-Tec Performance
    Replies: 43
    Last Post: 11-09-2013, 04:04 PM
  2. Still chaseing speed or am i just chaseing a dream
    By RXP TJEEZE in forum 4-Tec Performance
    Replies: 26
    Last Post: 08-17-2012, 10:13 PM
  3. Still chasing RPM loss!!!!
    By GPHOTROD in forum Yamaha PWC Performance (2-stroke)
    Replies: 11
    Last Post: 08-14-2007, 09:20 PM
  4. Still Chasing RPM loss
    By GPHOTROD in forum Yamaha PWC Performance (2-stroke)
    Replies: 1
    Last Post: 08-14-2007, 06:46 AM
  5. Still Chasing RPM loss
    By GPHOTROD in forum Yamaha PWC Performance (2-stroke)
    Replies: 1
    Last Post: 08-13-2007, 07:59 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
  •