pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Page 2 of 2 FirstFirst 12
Results 11 to 15 of 15
  1. #11
    PWCToday Newbie PiranahIndustries's Avatar
    Join Date
    Nov 2016
    Location
    Chicago, IL
    Posts
    26

    Re: 1986 JS550/750 Conversion Build

    Quote Originally Posted by fastgtfairlane View Post
    have you done anything on the pump besides just the impeller? such as bored nozzle or stubby pump cone?
    Thanks for the idea about the flame arrestors. The motor I picked up came with an extra set so I'll try this on one set and compare the two to see if there is any noticeable improvements. So far, the impeller is the only thing I've changed on the pump. I've got a second nozzle I plan to bore out before I ride next. I also have access to a 3D printer and wanted to try modeling and printing a stubby cone (or set of them) to experiment with that.

    3. Try a traction vent in the rideplate. Get a stock 550SX rideplate, they are longer than the earlier 550 plates and cheap and easy to find. Then cut a traction vent hole (1" semi-circle shape - curve facing aft) 1 cm aft of where the reduction nozzle attachs to the pump vein stator.

    4. Try a top loader Intake grate.
    The plate I had on there originally traction vent, but was shorter like the earlier plates. I've thought about welding on an extension, but I was quite impressed with the ocean pro plate so I think I'll stick with that for now.
    I trued the hull over the winter, so I'm thinking trying out a top loader intake grate is the next step. Thanks for the ideas!
    1987 JS550/750 Conversion
    1990 550sx - stock

  2. #12
    PWCToday.com Is My Home Away From Home theVetteman3's Avatar
    Join Date
    Jul 2008
    Location
    Chicago / Portage, MI
    Age
    35
    Posts
    3,840

    Re: 1986 JS550/750 Conversion Build

    Quote Originally Posted by PiranahIndustries View Post
    I live further south in Mokena, but if you ride in Portage, the lake we are on is about 30 minutes south near Three Rivers. If it would work out, it would be sweet to have an expert like you to look everything over and give me your opinion. Not sure when I'll be up next though, likely toward the end of July.
    Sounds good man, hit me up with a pm if you're interested to ride then. We will be out July 4th weekend (1st and 2nd) then end of the month as well, weekend TBD.

    We ride on Austin Lake in Portage or at our friend's lake in Battle Creek
    1985 JS550/800 "Pretty Red": Newmiller 800, Rhaas 750 pump conv. [56.3mph gps]
    2009 1100 SJ:
    Kawi 1100
    2009 SJ MINT:
    KP steering adaptor, Worx 228 intake [45.6mph gps]
    1987 WJ650:
    6M6, JD Intake Grate, 17/20, cheater pipe [42.4mph gps]
    1994 XiR: 830cc Superstock, PJS side draft, 13/18 swirl [53.7mph gps]
    1998 SXI PRO:
    3DR hull mods [TBD]



  3. #13
    PWCToday.com Is My Home Away From Home theVetteman3's Avatar
    Join Date
    Jul 2008
    Location
    Chicago / Portage, MI
    Age
    35
    Posts
    3,840

    Re: 1986 JS550/750 Conversion Build

    From a good amount of experimentation, we have found stubby pump cones give you a tiny increase in low end for a relatively larger decrease in top end. Try it and post up your own thoughts. I've had better luck incrementally messing with nozzle sizes.
    1985 JS550/800 "Pretty Red": Newmiller 800, Rhaas 750 pump conv. [56.3mph gps]
    2009 1100 SJ:
    Kawi 1100
    2009 SJ MINT:
    KP steering adaptor, Worx 228 intake [45.6mph gps]
    1987 WJ650:
    6M6, JD Intake Grate, 17/20, cheater pipe [42.4mph gps]
    1994 XiR: 830cc Superstock, PJS side draft, 13/18 swirl [53.7mph gps]
    1998 SXI PRO:
    3DR hull mods [TBD]



  4. #14
    I dream skis Bob Gruen's Avatar
    Join Date
    Jun 2013
    Location
    Atlanta, Ga
    Posts
    501

    Re: 1986 JS550/750 Conversion Build

    The JS hull gets unstable around 45mph. The topic has been discussed at length here on the forum, but in a nutshell the flat section in front of the pump is a bit too wide and it lifts the bulk of the ski's weight, pulling the pressure off of the chines. Nothing but scratches in front of the intake or fins on the flat of the ride plate will help.

    Bob

  5. #15
    PWCToday Newbie PiranahIndustries's Avatar
    Join Date
    Nov 2016
    Location
    Chicago, IL
    Posts
    26

    Re: 1986 JS550/750 Conversion Build

    I found some time last weekend to swap out the half-gutted stock water box with the coffmans, and it made some very noticeable improvements!
    To start - what was left of the baffle in the stock box had been blown out and was rattling loose in there. I didn't have any exhaust leaks, and the inlet/exhaust rivets still held - but I noticed a hesitation when getting on the throttle quick - a bit different than the first few times I rode.
    The coffmans box is quieter (slightly), but allows the motor to breath way more - eliminated the hesitation on the throttle, and gave me 2 mph on the top end.
    The swap took only 15 minutes - which isn't bad, but to anyone building a conversion ski now - an AM waterbox is a must.
    1987 JS550/750 Conversion
    1990 550sx - stock

Page 2 of 2 FirstFirst 12

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