Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 24
  1. #1

    1390 Build Questions

    I am going to be building an EFI 1390 from the ground up, piecing everything together. But I have some questions where my lack of knowledge shows

    So far I have a set of 1300r efi cases and stator, a HotRods T&W crank from CrankWorx and I've got 1200r PV Cylinders.

    Do I need to use a 1200r or 1300r head with the 12r pv cylinders and 13r cases? I know it's something with the annodes, but not sure what I can use, but I do know that the 13r head is 1 piece and the 12r is 2. So i guess my question is, can I use a 1300 head with 1200pv cylinders???

    Do I need a 1200r or 1300r FlyWheel? I know the 12r has 2 pickups on the flywheel where the 13r has 3... Do I need a 13r since I'm using 13r cases??? Or does it not matter?

    I already have 12r pv cylinders.... Should I buy 1200r exhaust manifolds? Then I was thinking I could send those off with the cylinders and have them matched.

    What do I do about the intake manifold? Being that I have 1200 pv cylinders and I am doing EFI?



    I've wore out the search button and haven't been able to find definite answers.



    Everyone's help is much appreciated!!!! I've already learned so much from you guys I look forward to learning a lot more as I go through this build. Thanks in Advance... John


  2. #2
    This is going to be and EFI motor yes?

  3. #3
    Quote Originally Posted by Pale Rider View Post
    This is going to be and EFI motor yes?

    It's going to be an EFI ski



    Oppsie thanks Andy!!!!

  4. #4
    WATER WOODY's Avatar
    Join Date
    Aug 2005
    Location
    Minden, Nevada, United States
    Posts
    10,664
    +1
    11
    Do you have all the EFI electronics? ECU,tank/fuel pump/etc....

    Cases need to have the pulse line holes filled unless you have 03' on up cases(efi/1300),use the 1300 head and gasket.Electronics,flywheel/stator etc need to be used.1200 cylinders are perfect for a 1390.I recommend the use of the 1200 exhaust manifold,and entire 1200 pipe.

  5. #5
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
    Join Date
    Nov 2005
    Posts
    6,194
    +1
    536
    Hello John going efi you must use all efi electronics including stator and flywheel. 1200 cylinders are great for 1390 BB use the 1200 head and you have the 1300 cases that will work fine, If you were to use 1200 cases all you would have to do is fill in the pulse pipes.
    Exhaust manifolds are the same. If you need any questions answered feel free to call me all the big bore efi ski's in Tampa are running 80 MPH. plus.

  6. #6
    I do have all the EFI electronics... This motor will be going into an 05+ GPR so all that stuff is already there.

    The cases I bought from James K... I know they are EFI cases, but I believe they are 06 or 07 cases. So I won't have to worry about filling the pulse pipes. (Thanks Jim!!!)

    So I am going to buy a 1200 manifold because they are cheaper than a 1300 manifold


    What is the reasoning behind using an entire 1200r exhaust? Rather than the 1300? So I'd need the manifold, u-pipe and stinger? Then use the 1300 waterbox?


    Also, If anyone has any gas power valves they want to sell.... Please let me know.... I will pay top dollar for them!!!
    .
    .
    .

  7. #7
    WATER WOODY's Avatar
    Join Date
    Aug 2005
    Location
    Minden, Nevada, United States
    Posts
    10,664
    +1
    11
    You can use the 1200 or 1300 exhaust.I just stated that i used the 1200 setup,both work.

  8. #8
    I'm going to buy a manifold from a pv ski. I was told they are tuned differently than those from a non pv ski. They aren't very expensive 20 bucks. That way I can send it out with everything else to have it port matched.

    What am I supposed to do on the intake side? Am I going to need an intake manifold from an efi ski????

  9. #9
    WATER WOODY's Avatar
    Join Date
    Aug 2005
    Location
    Minden, Nevada, United States
    Posts
    10,664
    +1
    11
    Are you running the VF3 reeds/spacer?

  10. #10
    Yes, I will be.... with stock throttle bodies for now.. maybe get aftermarket eventually

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. 1390 EFI Question
    By Gipper in forum Yamaha PWC Performance (2-stroke)
    Replies: 6
    Last Post: 08-13-2008, 10:46 AM
  2. GP1200R engine re-build questions
    By Metal4130 in forum Yamaha PWC Performance (2-stroke)
    Replies: 13
    Last Post: 04-02-2008, 08:46 AM
  3. GP 1300 Build Questions
    By dsolie in forum Yamaha PWC Performance (2-stroke)
    Replies: 4
    Last Post: 03-11-2008, 10:46 PM
  4. 1390 Build @ the right time
    By Gatorcountry in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 10-19-2007, 06:33 PM
  5. gp 1200 build question
    By carl sagan in forum Yamaha Old School Skis
    Replies: 19
    Last Post: 05-21-2007, 10:11 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
  •