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  1. #11

    Join Date
    Aug 2016
    Location
    Panama city
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    Kinda see where your are going....I run 1.5 seats, because the Mikuni Manual says they are the smallest seat that will flow all the fuel the carb needs...For popoff. 1.2 seat with 115g spring at 85psi vs 1.5 seat 115g spring at 55psi, will run the same on the engine in the real world. Note: Fuel pressure normall only varies from 1 to 6psi (800pv, after balancing mod is 1 to 4psi) and has very little effect with engine running popoff setting...On a running engine, it is done with venturi effect vacumm and some intake vacuum (restrictions) on the diaphragm, which compresses the spring, and allowing fuel pressure to pump it in, until fuel chamber is at the level to balance the venturi effects/vacumm on the diaphragm One step lighter spring allows the venturi effect/vacumm to unseat the needle earlier and increases fuel level slightly (riching the mixture)in the chamber prior to resetting the needle. (about one pilot jet size)..Thoughts?..kev
    Last edited by Crazypirate; 06-21-2017 at 09:33 AM.

  2. #12

    Join Date
    Apr 2016
    Location
    Clearwater, FLorida
    Posts
    13
    +1
    2
    I agree.

  3. #13

    Join Date
    Aug 2016
    Location
    Panama city
    Posts
    327
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    Cool..., Thanks for the discussion. Just got done testing xl800 with flame arrestors and a 95g spring...Did not like either,... FA added to much noise (did add 160rpm), and 95g springs where too rich with 110p & 150m (no accelerator)..So let's try 92.5p, 155m, 115 spring, accelerator, amd some small holes in a Stock FA to start with! (I liked the 160rpm, just want less noise....lol...

  4. #14
    So basically, on a stock 800 motor throw the 1.2's away...install 1.5's witha 115g spring and set the pop-off at around 50. Then water test and tune.

  5. #15

    Join Date
    Aug 2016
    Location
    Panama city
    Posts
    327
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    Use 115g spring, then either 1.2 seat (less chance of a dribbler) or 1.5 seat ( will flow all the fuel carb can handle)...As with most things it a give or take relationship....Except for the Balancing Mod in the FAQ section, that is a MUST DO mod (use an orginal 90 pilot for the return...... and I personally will not reuse original pilot jets on a PV motor, any slight corrosion/imperfections will lean it out even further then the emission lean jetting yamaha installed..( I presently have 92.5 in, versus 90 stock)...kev

    1.2 seats are fine for thousands of stock 800s...No aftermarket/modified flame arrestors, milled head, ect.
    Last edited by Crazypirate; 06-22-2017 at 08:31 AM.

  6. #16
    Maybe bringing an old thread to life but I need help. I installed the 1.5 seat but kept the 90 and 150 jet. What would my low/high speed screws initially be set to. Right now I start it up and it revs really high and I have to just kill it. Iím scared to let it run long and get hot and cause a run away. Iím going to adjust my cables as I think they might be too tight

  7. #17

    Join Date
    Jul 2019
    Location
    Buffalo, NY
    Posts
    616
    +1
    40
    If it revs up too high you either have an air leak around the carbs or the idle screw is out of adjustment

  8. #18
    Quote Originally Posted by Jonesyfxr View Post
    If it revs up too high you either have an air leak around the carbs or the idle screw is out of adjustment
    My accelerator cable was way to tight and pulling. I did seal everything now and the idle screw is all the way out. Will test tomorow and see what happens


  9. #19

    Join Date
    Jul 2019
    Location
    Buffalo, NY
    Posts
    616
    +1
    40
    Quote Originally Posted by Zulu989 View Post
    My accelerator cable was way to tight and pulling. I did seal everything now and the idle screw is all the way out. Will test tomorow and see what happens
    That’ll do it!!

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