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  1. #1
    cmherrera's Avatar
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    Pop off pressure 1.2 n/s

    What is the pop off pressure with 1.2 n/s gold spring??stock carbs


  2. #2
    Moderator OsideBill's Avatar
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    I tested some the other day and they popped at 90psi I had to put clamps on the hoses from my tester to keep them from blowing off.

  3. #3
    PolarisNut's Avatar
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    Do you guys get enough fuel with those tiny N/S setups? I know the experts say they "should" flow as much fuel as the engine can use, but I've personally found that they can cause issues. I tried 1.5s in a couple setups, and there was always a bog on WOT throttle application when coming out of a turn, that couldn't be tuned out with the pilots/low speed screws. Even if it was loading up rich at idle and in the mid, it would still hesitate. Low pop off, high pop off..still did it. Went back to a 2.0, and bam, it was gone. These were Novi's and Full Spectrum carbs, not stockers.

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    Moderator RX951's Avatar
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    http://www.greenhulk.net/forums/show...b+spring+color

    post #3. Will give you a rough reference of anything above 1.2. The lowest on the chart is 1.5. I would agree with what Osidebill said.

  5. #5
    cmherrera's Avatar
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    I had it up to 85-90psi. I thought it would never pop. Thanks bill.

  6. #6
    Moderator OsideBill's Avatar
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    Make sure you do it wet with WD-40, put some in the cavity and hold the needle valve open and allow it drain under the valve, then do the test.

  7. #7
    Moderator OsideBill's Avatar
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    Quote Originally Posted by PolarisNut View Post
    Do you guys get enough fuel with those tiny N/S setups? I know the experts say they "should" flow as much fuel as the engine can use, but I've personally found that they can cause issues. I tried 1.5s in a couple setups, and there was always a bog on WOT throttle application when coming out of a turn, that couldn't be tuned out with the pilots/low speed screws. Even if it was loading up rich at idle and in the mid, it would still hesitate. Low pop off, high pop off..still did it. Went back to a 2.0, and bam, it was gone. These were Novi's and Full Spectrum carbs, not stockers.
    Personaly I never run 1.2's, 1.5 is the smallest I will go. There is a good thread in the how to section on jetting specs for the GPR. The left turn bog goes away when you run the shafts perpindicular instead of parallel this was proven a long time ago, but I forget by whom.

  8. #8
    305coco's Avatar
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    Quote Originally Posted by OsideBill View Post
    Personaly I never run 1.2's, 1.5 is the smallest I will go. There is a good thread in the how to section on jetting specs for the GPR. The left turn bog goes away when you run the shafts perpindicular instead of parallel this was proven a long time ago, but I forget by whom.

    bill i see that when everybody rejets their carbs they put 1.5 n/s in there
    i tried them on my 1200r and could not tune it no matter what spring i put in there, it would always have a bog so i ended up with the stock 1.2 and stock springs and it runs great,
    ohh,,, and it has vf3's and heads which i assume would need more fuel but no matter what spring i put in there with the 1.5 n/s it would not run right

  9. #9
    Moderator OsideBill's Avatar
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    Quote Originally Posted by 305coco View Post
    bill i see that when everybody rejets their carbs they put 1.5 n/s in there
    i tried them on my 1200r and could not tune it no matter what spring i put in there, it would always have a bog so i ended up with the stock 1.2 and stock springs and it runs great,
    ohh,,, and it has vf3's and heads which i assume would need more fuel but no matter what spring i put in there with the 1.5 n/s it would not run right
    Not sure what the rest of your set-up looks like, but all I have worked with on the 1.5 run great. This was done back early in 00 by Fercho and has been a great mod ever since. Tried and used by countless people on here. When set-up with the rest of the jetting formula it works period. The VF-III's and head do not affect the jetting, Triple's or porting do.

    There are a lot of factors that will affect carb performance, RAD, F/A's or stock air box, water socks, fuel pressure, fuel supply etc.

  10. #10
    All hail the Chief! fullboogie's Avatar
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    1.5's are the way to go for the vast majority of us. If you're having tuning problems, there's either an issue with the tuning or with something mechanical (i.e. incorrect popoff). You've got to put some time into tuning these dang carbs, but once you have it it's cake.

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