Results 1 to 6 of 6
  1. #1

    1997 slt 780 piston question?

    I am rebuilding my engine over the winter and I have two good pistons and cylinders that are already bored 50 over. The third cylinder needs a bore job, would it be alright to run two pistons bored 50 over and one bored 60 or 80 over?

    Also does anyone have a good 780 head for sale?


  2. #2
    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
    Ther is no 60 or 80, but the next step up would be .75mm over.

    How badly damaged the cylinder is dictates what size piston it would need, A deep gouge may not be removed by going only 1 size over.

    Most aggree that keeping the pistons the same size are preferred, but 1 piston SLIGHTLY oversized should be acceptable. Most preferably in the CENTER cylinder for balance purposes.

    John Zigler just posted a 780 he's parting out, give him a shot. He's a great guy to deal with. MANY happy customers.

  3. #3
    john zigler's Avatar
    Join Date
    Aug 2006
    Location
    WI
    Posts
    2,545
    +1
    33
    Quote Originally Posted by xlint89 View Post
    Ther is no 60 or 80, but the next step up would be .75mm over.

    How badly damaged the cylinder is dictates what size piston it would need, A deep gouge may not be removed by going only 1 size over.

    Most aggree that keeping the pistons the same size are preferred, but 1 piston SLIGHTLY oversized should be acceptable. Most preferably in the CENTER cylinder for balance purposes.

    John Zigler just posted a 780 he's parting out, give him a shot. He's a great guy to deal with. MANY happy customers.
    thanks kevin!!

    yes, i do have a 780 here, we are about to take apart, but the motor is a good runner, and i do not wantto break down the short block. ( i would sell you the motor, if you want).

    personally, i would never run different sized pistons. i can get you a complete top send kit, with all three pistons, and gaskets at a pretty reasonable price. ( like kevin said, you ned to be sure what size you need). i also have cyls, and heads here.

    send me an email, if i can help out at all.

    thanks.

  4. #4
    Thanks for the advice, I guess I install the same size piston.

    I already have a new .50 piston and a new sleeve, around how much does it cost to get the new sleeve installed in the cylinder, or is there anyway to do it yourself?

  5. #5
    Quote Originally Posted by dustin88 View Post
    Thanks for the advice, I guess I install the same size piston.

    I already have a new .50 piston and a new sleeve, around how much does it cost to get the new sleeve installed in the cylinder, or is there anyway to do it yourself?
    for your cyl I would look for one in the bore size u need, a re sleeve is a little pricey

  6. #6
    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 Originally Posted by dustin88 View Post
    Thanks for the advice, I guess I install the same size piston.

    I already have a new .50 piston and a new sleeve, around how much does it cost to get the new sleeve installed in the cylinder, or is there anyway to do it yourself?
    If you've got the piston already, then just buy a used cylinder from John and have it bored to fit the .5 you have.

    It will be cheaper than re-sleeving a cylinder and then boring it .5mm oversized.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 1997 slt 780
    By randyz in forum Polaris Open Discussion
    Replies: 1
    Last Post: 07-19-2009, 11:12 PM
  2. 1997 SLT 780 issue
    By CamaroRacing12 in forum Polaris PWC Performance
    Replies: 6
    Last Post: 06-26-2009, 11:20 AM
  3. 1997 slt 780
    By oldcyfan in forum Polaris Open Discussion
    Replies: 6
    Last Post: 05-06-2009, 11:43 PM
  4. slt 780 idle question?
    By dustin88 in forum Polaris Open Discussion
    Replies: 6
    Last Post: 08-29-2008, 09:48 AM
  5. looking for engine for 1997 slt 780 or 750
    By jayzauto64 in forum Polaris Classifieds
    Replies: 2
    Last Post: 07-04-2008, 09:51 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
  •