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Another carb question

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  • Another carb question

    Looking for advice before I dig back in...
    Little history
    Only rode bike for 10 miles home after buying it and knew there were issues with the fuel system.
    It is a 98 750 with 24k on the odo
    Disassembled carbs and took note that they have been apart before with more than normal rust in bowls.
    Cleaned circuits with carb cleaner and air, reassembled with dynojet kit
    Had 114 main jet and replaced it with new 114 jet.
    Needle valve had the clip on #1 groove, replaced it and installed on #3 grove
    Set float height to 13mm and mixture screws 2.5 turns out.
    Ran bike with new ngk plugs, aux fuel tank.
    Idle fluctuated and wouldn't hold while attempting to sync carbs unless idle was set to 4k, sprayed carb clean around and unable to find any vacuum leaks. All pipes were hot and measured with infrared temp sensor.... cyl 1 was 265-280f cyl 2 and 3 was in mid 500's and 4 was in mid 600
    Reading carbs 101 it was said to set float height to 14.6.
    The bike has stock air box, new emgo air filter, new fuel filter, yosh pipe with stock headers.
    Any suggestions on settings and what to look...going to take them apart later today and double check everything again.
    Last edited by rperry03; 08-04-2017, 11:50 PM.

  • #2
    Hmm 13mm might make it run a little to rich

    Check this site helped me set my bike up
    “Anything that happens, happens. Anything that, in happening, causes something else to happen, causes something else to happen.
    Anything that, in happening, causes itself to happen again, happens again. It doesn’t necessarily do it in chronological order, though.”
    ― Douglas Adams


    • #3
      Thanks, I adjusted float height to 14mm and set mixture screws to 2.75 out. I disassembled, cleaned, inspected everything and ended up replacing the o rings on the jet needle stoppers, 2 were questionable. Not really sure what If that was an issue or not, but ran way better this go round all the way up to operating tempature. Haven't had a chance to sync them yet.


      • #4
        Your idle will change during syncing. You'll have to readjust back to 1800 rpm as you go. Any drastic change in idle indicates a severe imbalance between carbs..
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        • #5
          Thanks guys, sync carbs and all seems ok for now and will know more once I can test ride it....but I'll have to wait till front upper brake hose and grips arrive.
          Of course knowing nothing about the history of this bike the number 4 petcock/sync port was gunked up and busted off. Knocked out old piece, drilled and tapped a valve from the sync tool lol used thread sealer and o ring to seal.

          Last edited by rperry03; 08-06-2017, 04:35 PM.