Page 1 of 2 1 2 LastLast
Results 1 to 10 of 14
  1. #1
    skigolfnut's Avatar
    Join Date
    Jun 2009
    Location
    League City TX
    Posts
    1,979
    +1
    33

    785 Piston wash and domes questions?

    I had to take the ADA head off to see the wash after the last run,
    this is what I found, they look to be a little lean,
    first will be mag, then center then pto,

    The domes that were in say PO7823 on them,
    The other domes I have say PO7825 and PO7821 which ones would run the highest compression?


    the compression gauge I borrowed from Orielly auto was crap, it was reading 70-72-72 on the cylinders,
    then I went to the stock 785 wich runs 62 mph on gps and it was reading 50-51-51??

    I thing the gauge was junk,
    the piston walls look good on the race ski, I can still see the cross honning and they look clean,
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	new polaris 049.jpg 
Views:	72 
Size:	82.8 KB 
ID:	262786   Click image for larger version. 

Name:	new polaris 043.jpg 
Views:	69 
Size:	109.1 KB 
ID:	262787   Click image for larger version. 

Name:	new polaris 039.jpg 
Views:	70 
Size:	106.7 KB 
ID:	262788   Click image for larger version. 

Name:	new polaris 046.jpg 
Views:	52 
Size:	108.4 KB 
ID:	262789  


  2. #2
    785 Pro Mick's Avatar
    Join Date
    Sep 2006
    Location
    Homer Glen, IL
    Posts
    700
    From what I remember, the 7825's were about 160lbs and the lowest compression of the 3.

  3. #3

    Join Date
    Aug 2006
    Location
    Homer Glen Il.
    Posts
    8,702
    +1
    109
    the 23's should be around 170-185 lb the 21's are around 190-200

  4. #4

    Join Date
    Aug 2006
    Location
    Homer Glen Il.
    Posts
    8,702
    +1
    109
    the mag is starting to destruct around the egde
    the cen and pto are a touch lean but not that bad
    what octane fuel are you running ??

  5. #5
    skigolfnut's Avatar
    Join Date
    Jun 2009
    Location
    League City TX
    Posts
    1,979
    +1
    33
    I mix vp110 and premium pump gas around 92 octaine equally,
    and I use 40/1 oil ratio,
    it was hard to get a good picture of the mag piston with the sun,
    should I fatten up the highs or lows a little bit?
    what do you think is up with the mag?
    I still have that slightly bigger water line hooked up to that one?
    standing by,

  6. #6

    Join Date
    Aug 2006
    Location
    Homer Glen Il.
    Posts
    8,702
    +1
    109
    Quote Originally Posted by skigolfnut View Post
    I mix vp110 and premium pump gas around 92 octaine equally,
    and I use 40/1 oil ratio,
    it was hard to get a good picture of the mag piston with the sun,
    should I fatten up the highs or lows a little bit?
    what do you think is up with the mag?
    I still have that slightly bigger water line hooked up to that one?
    standing by,
    i would open the cen and pto an 1/8 of a turn on the highs and the mag a 1/4 turn on the highs and run a 75/25 mix on fuel 75 110 oct

  7. #7
    skigolfnut's Avatar
    Join Date
    Jun 2009
    Location
    League City TX
    Posts
    1,979
    +1
    33
    thanks

  8. #8

    Join Date
    Aug 2006
    Location
    Homer Glen Il.
    Posts
    8,702
    +1
    109
    get a good compression gauge also

  9. #9
    skigolfnut's Avatar
    Join Date
    Jun 2009
    Location
    League City TX
    Posts
    1,979
    +1
    33
    I will do that next,
    a better picture of the mag piston,
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	new polaris 047.jpg 
Views:	137 
Size:	116.3 KB 
ID:	262809  

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,327
    +1
    29
    Quote Originally Posted by 785 lugs View Post
    the mag is starting to destruct around the egde
    That's what I thought I was seeing too.

    Quote Originally Posted by 785 lugs View Post
    i would open the cen and pto an 1/8 of a turn on the highs and the mag a 1/4 turn on the highs and run a 75/25 mix on fuel 75 110 oct
    I agree with that ^^^, but maybe go a bit more than 1/4 out on the MAG. Better to be rich, and lean it out, then be too lean and hole/damage the piston.

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. Piston wash and ADA head domes part II
    By skigolfnut in forum Polaris Open Discussion
    Replies: 0
    Last Post: 02-02-2012, 08:29 PM
  2. Piston Washing and other questions
    By Chrisrokc in forum Yamaha PWC Performance (2-stroke)
    Replies: 14
    Last Post: 09-29-2010, 04:32 PM
  3. Piston Wash and Cylinder pics ?
    By SpeedJunky in forum Yamaha PWC Performance (2-stroke)
    Replies: 14
    Last Post: 03-04-2008, 10:24 AM
  4. Check piston wash and valves W/O taking off the head
    By 800AMSOIL4U in forum Yamaha Open Discussion
    Replies: 7
    Last Post: 09-14-2006, 07:15 PM
  5. Check piston wash and valves W/O taking off the head
    By 800AMSOIL4U in forum Polaris Open Discussion
    Replies: 2
    Last Post: 09-13-2006, 11:09 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
  •