650 jammer tuning question
pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    PWCToday Regular
    Join Date
    Jul 2011
    Location
    mn
    Age
    35
    Posts
    137

    650 jammer tuning question

    Well primary testing done, had to run really low popoff to get an off idle bog to go away, but then picked up a 1/4 throttle to wot rich bog (I think). Thinking a may have to trim a spring to get in between mikuni numbers. Any ideas?

    Stock 650 lx motor with an sbn 44, 120 pilot, 120 main, 1.5 ns, 65gr spring (gave me 28psi?) L screw at 1 1/4, H at 1 1/8. Choke delete and a screen in fa removed. Plugs at wot are a light brown and seems to hold a steady rpm for as long as I can keep it hooked up lol.

    With the stock 95gr spring I would get 36psi popoff (should be 43 right?), and it would almost die it had such a lean bog. Any ideas on how to get rid of that mid range rich spot but not loose the low end hit, if you call call it that lol.

  2. #2
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
    Join Date
    Aug 2006
    Location
    Al-ugh-bam-ugh
    Posts
    27,610

    Re: 650 jammer tuning question

    Install a 2.0 needle and seat with the 95 gram spring to lower the popoff
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  3. #3
    PWCToday.com Is My Home Away From Home Yamabooeey's Avatar
    Join Date
    Sep 2008
    Location
    City of Blasters
    Age
    57
    Posts
    6,887

    Re: 650 jammer tuning question

    2.0 and 80 spring and drop the main to 115 with aftermarket f/a
    Thanks to

    Optima Racing
    C57 Racing Products
    NorCal Watersports
    Newmiller Machines
    Boyko Racing
    Fly Racing
    Jettribe
    Impros
    Jettrim
    Traci Cottle Photography
    Greg Barnhart Photography
    Rhaas Products
    Rad Dudes
    DJSA Racing
    Serano Tile/Stone





  4. #4
    PWCToday Regular
    Join Date
    Jul 2011
    Location
    mn
    Age
    35
    Posts
    137

    Re: 650 jammer tuning question

    It's the stock fa, I just pulled 1 of the 3 mesh out of it and eliminated the choke plate and put a primer kit in.

    I don't think I would need to go to a bigger n/s, my idle to wot has no bog, but if I'm 1/4 throttle to wot it takes a sec or two for it to clear out and go. I wish I had a 115 main to drop in but won't be here tel next week. The thing is though I'm at 1 1/8 turns out on the high speed screws and the plugs are light brown at wot, and I wouldnt want to go any lower to be safe?

    Maybe I'm looking at it wrong but according to the manual it would be a pilot or main jet issue or a combo of them plus popoff?

  5. #5
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
    Join Date
    Aug 2006
    Location
    Al-ugh-bam-ugh
    Posts
    27,610

    Re: 650 jammer tuning question

    Quote Originally Posted by millnoff View Post
    It's the stock fa, I just pulled 1 of the 3 mesh out of it and eliminated the choke plate and put a primer kit in.

    I don't think I would need to go to a bigger n/s, my idle to wot has no bog, but if I'm 1/4 throttle to wot it takes a sec or two for it to clear out and go. I wish I had a 115 main to drop in but won't be here tel next week. The thing is though I'm at 1 1/8 turns out on the high speed screws and the plugs are light brown at wot, and I wouldnt want to go any lower to be safe?

    Maybe I'm looking at it wrong but according to the manual it would be a pilot or main jet issue or a combo of them plus popoff?
    Two people that know stuff just recommended you go with a 2.0 needle and seat, but you don't feel that you need to, if you got this then why post here ?
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  6. #6
    PWCToday Regular
    Join Date
    Jul 2011
    Location
    mn
    Age
    35
    Posts
    137

    Re: 650 jammer tuning question

    Quote Originally Posted by WFO Speedracer View Post
    Two people that know stuff just recommended you go with a 2.0 needle and seat, but you don't feel that you need to, if you got this then why post here ?

    I guess asking a question isn't allowed?

    I was just maki ng sure there was no dif between the stock fa with a screen pulled and an aftermarket fa? That is all, I wanted to be safe. Sometimes people read things wrong? Sometimes people write stuff wrong? You know that type of deal.

    Thanks for the help, I'll give it a shot today and see what happens.

  7. #7
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
    Join Date
    Aug 2006
    Location
    Al-ugh-bam-ugh
    Posts
    27,610

    Re: 650 jammer tuning question

    The popoff changes the way or the amount of fuel that can pass through the jets at a given RPM, this is why sometimes you can just change the popoff without fooling with the jets.

    1.5 is really a ridiculous needle and seat size that only works on bone stock skis with restrictive flame arrestors, free up the air flow and you need lower popoff and a bigger needle and seat.

    Actually all the needles are the same size, it's the hole in the seat that is larger or smaller depending on the needle and seat size, all this being said what you run into when you start modding stuff is that the fuel pump cannot push enough fuel through the small needle and seat to keep the fuel chamber full of fuel, this is when you move up to a larger needle and seat.

    Personally I want more than enough fuel flow so it will not lean out thus my recommendation for the 2.0 needle and seat.

    There it is more info than you ever wanted to know about needle and seat sizes.
    Last edited by WFO Speedracer; 07-16-2016 at 02:21 PM.
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  8. #8
    PWCToday.com Is My Home Away From Home
    Join Date
    Oct 2013
    Location
    funky town
    Age
    89
    Posts
    7,401

    Re: 650 jammer tuning question

    Are you sure?
    I'm only here to make you mad



    I'll tell your girl you said "hi".


  9. #9
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
    Join Date
    Aug 2006
    Location
    Al-ugh-bam-ugh
    Posts
    27,610

    Re: 650 jammer tuning question

    No all of tHe above is just BS
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  10. #10
    PWCToday.com Is My Home Away From Home jetskijockey's Avatar
    Join Date
    Dec 2007
    Location
    Eau Claire, WI
    Posts
    2,947

    Re: 650 jammer tuning question

    Let's all get drunk and party!


    Sent from my iPhone using Tapatalk

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

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

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0