Carby NT Carb Tuning Basics

crassius

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#81
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
 


mrbg

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#83
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?
 
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#86
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.
 

crassius

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#87
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
 
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#90
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.
 

mrbg

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#91
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.
 
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#92
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.
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.
 
E

Ed kendall

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#94
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
 

Chreelou

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#95
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
Did you ever figure out the issue? Mine is doing same thing..
 

gary55

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#96
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
Check for proper torque on the head bolts, could also be a jetting issue.
 

Chreelou

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#97
Check for proper torque on the head bolts, could also be a jetting issue.
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
 

JAM Power

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Jim, first point - it's not good practice to 'serial post', effectively replying to yourself. Better to edit your first post to add afterthoughts. It keeps the thread neater.

Regarding changing the float level, you said it yourself:- "my float tang was bent"
To adjust the float level, you bend the little brass tangs that contact the top of the float.

Is normal for it to be bent (for the cost and materials of those NT Carbs) but you can un-bend it with a hammer. Soft, very soft please. Put it upside down over a flat surface and with a wood block over the beñly of thr float tank you can give soft knocks to correct the problem.
 

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