Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 21
  1. #1
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31

    780 head on a 750. Any problem?

    I bought an OP 780 head that is written 26cc on it. Besides checking squish, does anyone see a problem with me using it on a 750 bored .20 over? Thanks


  2. #2
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Location
    Campbell, Ca.
    Posts
    14,100
    +1
    105
    Does the bore size match that of the dome?
    If it does, I'd install it and check compression to see what what fuel you'll need to run.
    Then like you said check the squish and see if you need to alter it.
    I'm not home so I don't know the bore size of the 780 stock versus the 750 .020 over.

  3. #3
    Bing-A-Ding-Ding-Ding, Brrrrrap! Brrrrrrrrrap!!! Polaris_Nut#1's Avatar
    Join Date
    Aug 2006
    Location
    Pittsfield, MA
    Posts
    3,350
    +1
    26
    I bought one of those heads on ebay years ago for my 750 and then resold it after talking to GroupK or somebody I can't remember. Whoever it was said that the single heads seal better because you don't have to worry about any height differences between cylinders (could possibly blow the gasket out). Definitely check your compression. They might be fine. Anybody running them that would like to tell us about them?

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    OK those are the checks I intended on doing, just seeing if someone had another take on it. Thanks

  5. #5
    Water Bum Rodneyae's Avatar
    Join Date
    Dec 2006
    Location
    Roanoke, Va
    Posts
    3,083
    Send it to me. LOL I will give it a year or two of checking. LOL

  6. #6
    Bing-A-Ding-Ding-Ding, Brrrrrap! Brrrrrrrrrap!!! Polaris_Nut#1's Avatar
    Join Date
    Aug 2006
    Location
    Pittsfield, MA
    Posts
    3,350
    +1
    26
    Cool let us know how it works out for ya. I never hear anything about them on here.

  7. #7
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Location
    Campbell, Ca.
    Posts
    14,100
    +1
    105
    I've heard detonation is the issue with those domes due to their little twist and lack of squish. If you are using original parts and gaskets, I've never seen any of them lose a gasket but then again I've never seen a 750/780 lose a cylinder due to detonation caused by the OP dome assembly.
    I have one I'm using right now, it's been working great for roughly 4 months.

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    [quote=.
    I have one I'm using right now, it's been working great for roughly 4 months.[/quote] What do you have it on? I'm planning on using this little baby on the 650/750 conversion with the PSI dry pipe, V Force II, PRO 785 CDI and aluminum flywhweel with stocjk 38mm carbs. It's going to be a real arm jerking, wave jumper for my girl.

  9. #9
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Location
    Cleveland OH
    Posts
    17,330
    +1
    31
    I don't think this is going to work without some modifiying. FYI: a 780 head won't fit onto a 750 cylinder without elongating the holes and vice versa.

  10. #10
    Water Bum Rodneyae's Avatar
    Join Date
    Dec 2006
    Location
    Roanoke, Va
    Posts
    3,083
    Then the 650 head might not fit my 780 heads that I have. I will try tomarow, and let you know.

    R

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Can I use 780 carbs on a 750?
    By SlpFirehawk415 in forum Polaris How To & FAQs
    Replies: 3
    Last Post: 05-26-2015, 06:13 AM
  2. high comprssion heads on sl 750 or 780
    By lxman88 in forum Polaris PWC Performance
    Replies: 8
    Last Post: 09-19-2010, 11:05 PM
  3. Milled heads on a 750
    By roscofisher11 in forum Polaris Open Discussion
    Replies: 11
    Last Post: 12-09-2009, 07:25 PM
  4. Pro 785 head on a 750 or 780???
    By jkindt in forum Polaris PWC Performance
    Replies: 4
    Last Post: 11-30-2009, 05:22 PM
  5. 780 carbs on a 750
    By gvnitup in forum Polaris Open Discussion
    Replies: 8
    Last Post: 05-14-2007, 12:36 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
  •