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  1. #1

    GP1300R Basic Mods - good or bad?

    Hi all from the UK. Just joined the forum having bought a GP1300R a few weeks back and wanted to start by picking your brains to point me in the right direction! Basically I have decided to invest some cash in doing some mods to my GP1300R and have come up with the following list of stuff to do:

    D plate and cat con (already done as cat was broken up)
    Solas 13/19 prop (already done when I bought it)
    Riva 2 bar top loader intake
    87mm nozzle
    Pump seal kit

    The question is that is this a good basic set up or am I wasting money anywhere? I am thinking of leaving the ride plate stock and the same for the sponsons - what do you guys think? Or should I actually be doing something else as well?

    I don't want to go to the expense or hassle of a full Riva Stage 1 or 2 upgrade as I don't use the ski that much.

    I am also a little unsure about the 87mm nozzle as I don't really see what it will do for me over the stock 85mmm nozzle (2mm doesn't seem much!) however trawling back through previous threads on here seem to indicate its a good thing to do - why?

    Finally the ski also came with a new Solas 14/20 in a box. From what I can see the 13/19 is a better prop for low down performance but is this true - also is it worth keeping the 14/20 if the mods I want to do will be mild?

    Sorry there are so many questions but best get them off my chest all at once!!

    Any help would be appreciated.

    Thanks

    Nick


  2. #2

    Join Date
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    phil did a nice job on starting points

    http://rivaforums.com/eve/ubb.x/a/tp...4/m/9511019071
    read that then come back here

    later cd

  3. #3
    Moderator RX951's Avatar
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    Welcome to the Forum Nick98 !

    check these two threads out


    STEP by STEP - One alternative to building a fast rec ski.
    http://www.greenhulk.net/forums/showthread.php?t=8829


    Looking to get over 70 with ease
    http://www.greenhulk.net/forums/showthread.php?t=8380&highlight=gp1300r+mods

  4. #4
    One question for you that will make a big difference in some of your parts to purchase is what year 1300 is it? 05 and 06 were set up a little different than previous years. Depending on the year I like the DF 14/20 with even a stock motor on my 05.

  5. #5
    qbzonk's Avatar
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    in order to help you better, let us know what type of riding you are trying to set this ski up for. Are you going to race it? Do you want it to handle better and don't care about speed or do you want more top end and could care less about handling?

    Keep us posted.

  6. #6

    Red face

    Thanks for the help so far guys. The links are a really good read but I think they are a bit extreme for what I am trying to do - I don't really want to strip the engine as it is good enough for me stock.

    As for what I want to use it for then not really racing just good all-round recreational use. I am a bit of a speed freak but the waters off the UK don't often allow for flat out performance as the sea is too rough. Where I live there are no lakes or inland waterways so saltwater it is! Thus better handling, faster acceleration with not much loss of top end would be my dream ticket.

    I started on the mod route simply because the cat was broken up so did the d-plate and 'cat con' mod. The Solas was already on there so then I thought what next?

    Having looked at forums on here (and another well known site !!) it seems the GP1300Rs suffer from cavitation and porpoising and the standard mods seem to be intake grate and stepped sponsons (I have actually done the stepped sponsons mod today in the garage).

    The intake grate then made me think that I needed to do the pump seal kit to get maximum benefit (well thats what I read anyway!).

    But being a newbie I don't really know if thats the best use of my cash?

    As for the 87mm nozzle then as per my first post I don't really know what that will do for me - it just seems that everyone does it !!

    By the way - in reply to another question it is a 2003 model with 87 hours on it.

    Thanks in advance for continued help.

    Nick
    Last edited by Nick98; 08-27-2006 at 03:16 PM.

  7. #7
    Chrisrokc's Avatar
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    Quote Originally Posted by Nick98
    Thanks for the help so far guys. The links are a really good read but I think they are a bit extreme for what I am trying to do - I don't really want to strip the engine as it is good enough for me stock.

    As for what I want to use it for then not really racing just good all-round recreational use. I am a bit of a speed freak but the waters off the UK don't often allow for flat out performance as the sea is too rough. Where I live there are no lakes or inland waterways so saltwater it is! Thus better handling, faster acceleration with not much loss of top end would be my dream ticket.

    I started on the mod route simply because the cat was broken up so did the d-plate and 'cat con' mod. The Solas was already on there so then I thought what next?

    Having looked at forums on here (and another well known site !!) it seems the GP1300Rs suffer from cavitation and porpoising and the standard mods seem to be intake grate and stepped sponsons (I have actually done the stepped sponsons mod today in the garage).

    The intake grate then made me think that I needed to do the pump seal kit to get maximum benefit (well thats what I read anyway!).

    But being a newbie I don't really know if thats the best use of my cash?

    As for the 87mm nozzle then as per my first post I don't really know what that will do for me - it just seems that everyone does it !!

    By the way - in reply to another question it is a 2003 model with 87 hours on it.

    Thanks in advance for continued help.

    Nick
    Hey whats up, I am the guy that is the focus of one of the threads posted. I think the BEST bang for the buck would be a "MODDED" ride plate from island racing or jim if you can get one. Add 4mph on the top end or so and involves a little bit of grinding on the pump nozzle and stuff for it to fit. Right now I have a stock R&D plate but plan to get it modded out this winter.

    I have...

    Riva GP1300R Intake Grate
    Riva Pump Plug Kit
    2005 Pump
    14/20 Dynafly
    R&D Rideplate (stock for right now)
    Riva Race Flame Arrestor
    Riva D-Plate
    Riva EFI Controller
    Drilled front bucket and hood under the visor

    I have a 87mm nozzle I am going to play with even though I don't think I will see any gain from it on this pump. I also plan to possibly take out the bildge line in the nozzle to see if there is any gain. I am going to buy a gp800r grate when I get the chance to see if that helps too.

    GOOD LUCK in your hunt for cheap and easy speed! I say get the ride plate, screw the bigger nozzle, and get a impeller. D-plate is also a good idea! That should get you 70 mph possibly. If not throw on a gp800r grate and that should help some.

  8. #8
    Chris

    Sorry - I read the first link which seemed to be going down a road of serious upgrade and didn't see the second link to your thread

    Now checked it out and very useful. Looks like I will better off keeping the 85mm nozzle as I don't think I will change the pump yet (unless I can find a used one for sensible money)

    Am I still right in thinking that with a two bar top loader intake I will need to do the pump seal kit?

    Thanks

    Nick

  9. #9
    Chrisrokc's Avatar
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    Quote Originally Posted by Nick98
    Chris

    Sorry - I read the first link which seemed to be going down a road of serious upgrade and didn't see the second link to your thread

    Now checked it out and very useful. Looks like I will better off keeping the 85mm nozzle as I don't think I will change the pump yet (unless I can find a used one for sensible money)

    Am I still right in thinking that with a two bar top loader intake I will need to do the pump seal kit?

    Thanks

    Nick
    Yea do the Intake Grate and Seal kit at the same time.

  10. #10

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    Nick

    Yoiu are headed in the right direction. Sealing the pump and getting a double bar 1200 intake and sealing the pump are the right choices. They will help in any direction you decide to take your GPR as far as modification. They are the "must do" mods. Another "must do" is to make absolutely sure that your shoe is recessed as much as possible with a lot of sealant between the shoe and transom plate.

    You do not need a "kit" to seal, but the shoe area does need to be sealed. Some guys have simply bought a couple of tubes of silicone and filled all of the dips and cut outs on the shoe, then sealed it all into the hull. Using sillicone as a sealant is much cheaper (and messyer), but it will perform its function. Save your money and use silicone. Do a search on pump sealing... there is a discussion on this issue. Others have done it.... myself included.

    By far and without a doubt, the 3 degree nozzle is the single best modification you can do for your GPR in ocean water. It will cause a 1.5 to 2mph loss in smooth water, but will out perform in every way shape and form a 5 degree nozzle in water over 2 foot high. In water over 3 feet (1 meter), it will outperform the 5 degree in top speed and reduce rider fatigue.

    I use to race in ocean water and would never consider racing with a 5 degree nozzle.

    To regain the top speed that you would loose with the 3 degree nozzle, modify the ride plate like others have suggested.

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