Page 1 of 2 1 2 LastLast
Results 1 to 10 of 19
  1. #1
    ryanf117's Avatar
    Join Date
    Jun 2012
    Location
    Bloomingdale, Illinois, United States
    Posts
    32

    rear piston scoring ?

    bought my ski about two years ago, it didnt run right when i bought it took the head off and the rear cylinder was scored. i replaced the piston and had the cylider fixed. i was told the carb for that cylinder needed to be rebuilt, so i had it rebuilt. after having everything fixed i took it out about six times, the 6th time a cooling line poped off and lets just say it needed a top end again that rear cyilinder was the worst out of the three and it needed to be sleeved, after having it all fixed again it went into storage for winter. i took it out this year and only got about three hours out of it, and it started running like shit, took the head off and the rear cylinder was scored again, the other two are perfect. WHATS GOING ON ???? CARB ? each carb has its own fuel line to tank. also when it started running like shit the cylinder that got scored the air filter had fallen off


  2. #2
    A child of five would understand this. Go get one. pierowman's Avatar
    Join Date
    Sep 2011
    Location
    Seattle, WA
    Posts
    280
    +1
    7
    Check oil lines. Sounds like the problem has never been root caused so you keep fixing it over and over again. If the oil has been blocked off, are you premixing and at what ratio?

    You said cooling line popped off, does water come out of all the pissers? There could be a blockage if not.

    What ski are we talking about here?

  3. #3
    ryanf117's Avatar
    Join Date
    Jun 2012
    Location
    Bloomingdale, Illinois, United States
    Posts
    32
    premix 50:1 yea water is coming out of pisser

    thanks

  4. #4
    ryanf117's Avatar
    Join Date
    Jun 2012
    Location
    Bloomingdale, Illinois, United States
    Posts
    32
    it came off last year, not because of it being blocked but because the hose clamp was lose.

  5. #5
    A child of five would understand this. Go get one. pierowman's Avatar
    Join Date
    Sep 2011
    Location
    Seattle, WA
    Posts
    280
    +1
    7
    What model ski are we talking about?

  6. #6
    ryanf117's Avatar
    Join Date
    Jun 2012
    Location
    Bloomingdale, Illinois, United States
    Posts
    32
    97 gp1200

  7. #7

    Join Date
    Aug 2006
    Location
    Indiana
    Posts
    1,274
    +1
    81
    You should check the carb and gaskets for leakage, but also do an engine pressure test to see if you have an air leak. A leaking rear crank seal will cause the rear cyl to run lean and score the piston pretty easily. The info on how to do that is in the FAQ section.

  8. #8
    ryanf117's Avatar
    Join Date
    Jun 2012
    Location
    Bloomingdale, Illinois, United States
    Posts
    32
    thanks ! if i do a leak down dose it matter what position the piston is in ? and could i do a cylinder at a time, or should i have them all plugged when i test it ?

  9. #9
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    A 2 stroke leak test is way different then a typical 4 stroke leak down test you are talking about. In a 2 stroke, the crankcase is "part" of the intake manifold (so to speak) so you need to see if its leaking anywhere. Most commonly the rear crank seals in situation you're having.

  10. #10
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    GP1200 65U pressure test
    pressure Testing a 65U SUV
    Pressure Testing

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. 07 gpr lost rear piston
    By Bryonjodinolan in forum Yamaha PWC Performance (2-stroke)
    Replies: 29
    Last Post: 06-30-2016, 09:26 PM
  2. Oil lines good,pressure tested,reeds look good still toasted the rear piston ??? Help
    By chevydog in forum Yamaha PWC Performance (2-stroke)
    Replies: 11
    Last Post: 07-10-2013, 10:48 PM
  3. Carb issue? too much fuel going to rear piston.
    By Integragated in forum Yamaha PWC Performance (2-stroke)
    Replies: 3
    Last Post: 08-08-2012, 09:23 AM
  4. Piston scored, where to go from here? (sl700)
    By jared4brack in forum Polaris How To & FAQs
    Replies: 9
    Last Post: 01-16-2012, 05:43 PM
  5. GP1200r rear piston lunched
    By BombThreat in forum Yamaha Open Discussion
    Replies: 0
    Last Post: 08-01-2010, 07:33 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
  •