Carby NT Carb Tuning Basics

Discussion in '2-Stroke Engines' started by AussieSteve, Dec 27, 2009.

  1. crassius

    crassius Well-Known Member

    if you have acorn nuts on those studs, be sure they're not binding at the top - either break the tops off, replace with regular nuts, or add enough washers to give them more room inside
     

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  2. mrbg

    mrbg Member

    Ya i got rid of the acorns
     
  3. mrbg

    mrbg Member

    I was riding home last night and my bike started actin funny, it would die when I stopped it would start with full choke and run while I fiddled with the choke between open and closed. I made it home, luckily I was only 2 mi.out. today I cleaned up the motor and started process of elimination fuel line, filter, sparkplug dry n tan. I pulled the carb slide out and the mainjet had rattled out so I pulled the carb cleaned the jet put loktite on,figured while it's open I'll check float height it was at 5/8" or16mm i set it 21mm,i took it for a ride it runs good @WOT,but it has flat spot in the middle, needle is set on topnotch. Anyone have a suggestion?
     
  4. butre

    butre Well-Known Member

    sounds lean
     
    mrbg likes this.
  5. mrbg

    mrbg Member

    Ya I was gonna raise the needle a notch and see that helps or raising the float a hair
     
  6. rcastro3185

    rcastro3185 New Member

    So do i need a new main jet?

    My bike starts to choke out? Bog down? After 75% trottle. Does that mean its to rich or lean? What size main jet would i need? Please help thank you.
     
  7. crassius

    crassius Well-Known Member

    could be too rich, but 2-strokes will do this of revs aren't high enough to take extra throttle opening - if you are slowly building up speed & this happens, I'd try lowering float level to see what happens & if it helps, I'd try a smaller jet
     
  8. willwills90

    willwills90 New Member

    hey guys, what is the advatage of these 35 euro high performance racing carbs anyway?
     
  9. crassius

    crassius Well-Known Member

    they allow more air to flow when you have made performance mods to the motor
     
  10. bikejock

    bikejock Member

    Great tuning tips for the NT. This little carburetor is a good design. Simple & way less quarky than the 4 stroke carburetors the HS142 Honda clone engines use which I've had nothing but problems with. The NT carbs almost never seem to fail & are easily modifiable. I replaced a 4 stroke carb with the 2 stroke NT carb on my HS142 4 stroke engine & it starts up every time with no issues. Gas mileage seems to be a bit less with the NT carb on there but I think it was worth it.
     
  11. mrbg

    mrbg Member

    I got a email about using the the NT on the Huashang. Where's the info for swapping out the stock carb with the NT ? I've got a NT with 66 thru 70 jets, I'm at 100' ASL.
     
  12. bikejock

    bikejock Member

    I use a manifold adapter I bought from bikeberry. Had to get shorter bolts & cut out a new gasket for it though but works like a charm.
     
  13. mrbg

    mrbg Member

    Thanks I'll take a look on bikeberry . what about the jet
     
  14. Ed kendall

    Ed kendall Guest

    Me and my son are building a motorized bike it's sort of a cheap 80cc black motor but we ordered us high performance carburetor the motor is bogging down when we give it gas and not running properly we can hear that I've tried changing the spark plugs do you have any ideas on how I might be able to make this motor run better it will barely pull you down the road without pedaling thanks for your time
     
  15. Chreelou

    Chreelou New Member

    Did you ever figure out the issue? Mine is doing same thing..
     
  16. gary55

    gary55 Well-Known Member

    Check for proper torque on the head bolts, could also be a jetting issue.
     
  17. Chreelou

    Chreelou New Member

    Torque is good on bolts i did indeed check those. It's odd because it ran fine had to replace the throttle assembly though it went together good bike runs good, just bogs when given throttle
     
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