Results 1 to 5 of 5
  1. #1

    bought 780 rebuilt no compression

    The guy I bought this off of said it was rebuilt and it has new pistons and the cyl. have been bored out.My question is will it have compression if it isnt timed which he didnt do he said?

  2. #2
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Campbell, Ca.
    If it cranks and it's assembled, it has to have compression, timed or not.

  3. #3
    somthing is def wrong! hope it's the gauge! even a finger on the plug hole can confirm some compresion! zero is hard to do! even for the worst engine builder! maybe 650 pistons in a 785 would do zero

  4. #4
    Your right the engine fired aftrer I took off the head bolt acorn nuts and used the ones that are open at the top I guess the nuts were bottomed out.Awesome compression now all I have to do is figure out the triple fuel pump hookup.The motor starts right up when I put fuel in the carbs.It only has a gallon of gas in it will the pump pick it up?They installed a primer and took out the choke for some reason.Will an electric pump work?

  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    It should pick up a gallon of gas as long as the ski isn't too tilted up or down.

    I advise against an elec fuel pump.

    You'll need to wire it, then regulate it. Just buy another fuel pump from John Zigler for $26 USD.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Replies: 26
    Last Post: 08-19-2010, 08:00 PM
  2. 780 Mods no water separator and primer instead of a choke
    By johnnyrod in forum Polaris How To & FAQs
    Replies: 7
    Last Post: 07-27-2008, 10:37 PM
  3. Yamaha no compression on middle cylinder
    By mbateman55 in forum Yamaha Old School Skis
    Replies: 1
    Last Post: 08-23-2007, 10:56 PM
  4. Just bought sl 900 no spark
    By slxcrazy in forum Polaris How To & FAQs
    Replies: 15
    Last Post: 03-20-2007, 08:48 PM
  5. 1300 no compression rear cylinder
    By OCFZR in forum Yamaha PWC Performance (2-stroke)
    Replies: 25
    Last Post: 08-31-2006, 08:05 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