SBT Jetski Engines, Parts & Accessories

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  1. #1
    Joined
    Apr 2012
    From
    ocala,fl
    Posts
    14

    Default 01 gp800r need some help/advice on pop off pressure

    Just got another gp800r got a good deal since it needed carbs rebuilt,has 120psi on both cyl and motor has been leak tested with no leaks.my issue is after going through carbs with mikuni kits and installing riva flame arrestors ,choke butterflies still remain,my issue seems that even with the high speed needles at almost 3 turns out,i still can't get enough fuel and the plugs are white.I have only made a few quick attempts to get a reference so i dont damage the engine.I also rejetted the rear cyl main jet up from a 155 to a 157.5 to match the front cyl as recommended by group k to prevent seizing the rear cyl with flame arrestors.all the info I can find on f/a settings for these carbs is 1-1/2 out on the low and 1-1/2 out on the highs and no info on pop off and I'm way past that setting and should have black plugs in theory.my pop off was set at 75psi which is in the middle of the specified range.when I went through the carbs I installed new 1.2 needles and seats which are stock size.I was wondering if you guys have any info as to what my pop off should be with flame arrestors and if its possible to accomplish it with my 1.2 needles or will I have to go up to a 1.5 or will that be too much since engine is stock and flame arrestors and a riva free flow tube that gets rid of the silencer box after the waterbox

  2. #2
    Joined
    Apr 2012
    From
    ocala,fl
    Posts
    14

    Default Re: 01 gp800r need some help/advice on pop off pressure

    I'm running premix amsoil dominator 40:1
    Also

  3. #3
    Joined
    Mar 2003
    From
    SBT
    Posts
    21,545

    Default Re: 01 gp800r need some help/advice on pop off pressure

    Lower the pop-off to about 45 since your running the aftermarket flame arrestors.
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  4. #4
    Joined
    Apr 2012
    From
    ocala,fl
    Posts
    14

    Default Re: 01 gp800r need some help/advice on pop off pressure

    I was able to get it down to 50psi with a diff spring,both carbs are exactly at 50psi and needle only drops 2psi before closing,so i got both set perfect,I will put it back in water tomorrow and see how it affected it and inform you on the results,I would much rather tune out a rich condition,rather than shell a motor trying to richen it up

  5. #5
    Joined
    Apr 2012
    From
    ocala,fl
    Posts
    14

    Default Re: 01 gp800r need some help/advice on pop off pressure

    I also noticed when ski sit tank builds pressure like its supposed to,but running it has no pressure,what would cause this,I have pressure tested the system,gushed doesn't drop at all and double checked everything with soapy water and I have no leaks at all,filter is new,I pulled and inspected sending unit and replaced and tested check valve and gas cap seal

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