good power-no idle

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leo

leo

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Jul 20, 2015
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southern wv
i just took off my rt carb until i get around to ordering a new jet set, and put my nt carb back on.
it runs MUCH better, but dies as soon as i let go of the throttle. i'm thinking it just needs cleaned out, but am unsure if a partially stopped up jet could cause this. there doesn't seem to be any air leaks, none that i found anyway...
i also had a hollow banana pipe on, i put the stock muffler back on thinking maybe back pressure issue, but it started raining before i could test that one.

i took the nt off a month (or so) ago and it was fine then, would das dry out and stop it up that fast? any other suggestions i should look at?

as always, any advise is greatly appreciated.

Leo
 
crassius

crassius

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Sep 30, 2012
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if your idle screw is all the way in, that usually means you need to drop the needle a bit
 
2door

2door

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Sep 15, 2008
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Littleton, Colorado
Is you clutch disengaging completely? Maybe you need to tighten the clutch cable just a bit. Or, as Crassius suggested, maybe it's as simple as an idle speed screw adjustment. In is faster idle, out slows the idle speed. It is not an air/fuel adjustment screw but simply a mechanical stop that determines how far the throttle can close.

Tom
 
leo

leo

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Jul 20, 2015
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southern wv
it's on the bottom notch now, still running nearly wide open. the idle screw doesn't seem to make much difference either. i turned it out and the engine just died.
 
leo

leo

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Jul 20, 2015
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yes 2 door, the clutch is disengaging as it should.
but the engine is not going down to idle speed. it just revs up and stays there.
 
crassius

crassius

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Sep 30, 2012
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bottom notch is raising the needle - you'll want the clip set nearer the top to lower the needle
 
Chaz

Chaz

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Jun 3, 2012
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Vancouver, British Columbia
Leo, your high idle issue sounds like the cable may not be the right length. Maybe you can adjust it? Also have you checked the throttle slide in the carb to see if it's going all the way down?

When I say length I mean the ratio of inner cable to outer sleeve.
 
leo

leo

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Jul 20, 2015
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southern wv
it has the same cable it had before, and i have tried the clip at all of it's settings. it's in the middle now.
sometimes it goes wide open, sometimes it just dies. idle screw has little to no effect either way.
i re-re-rechecked the cable, slide mechanism, float, and bowl. all seem fine, no leaks found.
when i hold down the clutch, it will either go WOT, or die...
 
2door

2door

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Sep 15, 2008
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The throttle cable for the NT and the RT is not the same length. They aren't interchangable.

Also a high/fast idle is a symptom of an air (vacuum) leak somewhere downstream of the carburetor. Check the intake manifold gasket first. It's usually the culprit. Crankshaft seals can also be a problem. A bad seal will give you a high idle and will impact overall performance.

Tom
 
leo

leo

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Jul 20, 2015
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southern wv
the carb and cable on it now are the stock ones that came with the motor.
i am going to go ahead and get a gasket set and a jet set, sooner or later i will need them all, i'm sure...

does this look decent for the gasket set??
http://www.ebay.com/itm/Complete-En...0CC-/281270744292?hash=item417d0af4e4&vxp=mtr

and this one for the jets...
http://www.jnmotorsbikes.com/product_p/jnm1130.htm

one more thing, on my stock carb, the jet looks to be a long one. not like those pictured above. it screws in to the top the bowl housing and goes down into the center of the float. the head (the jet itself, at the bottom) doesn't screw off. total length is around an inch or so, one piece brass.
 
2door

2door

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Sep 15, 2008
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Littleton, Colorado
I believe if you look closely you'll see the jet does in fact screw into the brass tube. Most of the tubes have wrench flats and the jet has a screwdriver slot. I have a seen a couple of NT tubes that did not have the flats so they required using vice grips to loosen the jet. Just don't over do it with vice grips. Clamp just tight enough to allow the jet to unthread. As a rule they aren't super tight from the factory.

There are inconsistancies. I've seen tubes that were hexagonal their full lenght and some are cylindrical. Some have wrench flats, some don't. I've also run into a couple that were oversized and wouldn't fit through the center hole in the float from another carburetor. All were NT carbs.

Tom
 
leo

leo

Member
Jul 20, 2015
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southern wv
you are probably right 2door, i more than take your word for it... lol

i guess i will probably get the ones posted earlier... http://www.jnmotorsbikes.com/product_p/jnm1130.htm

0.68,0.70, 0.72, 0.74,0.82 and 0.84 should have fairly wide range for testing, dial it in better later if needed.
and the gasket set, can't hurt to have spares.

oh well, i'll put it back the way it was until i get them.

all i know for sure, is that tomorrow is opening day of squirrel season, buck season opens in 2 weeks... ;-)

thanks again man, very much appreciated.

Leo
 
crassius

crassius

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Sep 30, 2012
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not in shop right now, but as I recall hex tubes have pointy needle with more taper while smooth tubes have blunt needle with less taper - smooth tubes usually run leaner
 
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