carb size??

rwalton3563 · Jul 16, 2009

anyone have info on the carborator thats on the china 80cc?? like what the size of the bore is? or how to measure the carb?....any info is helpful...i was thinking about getting a carb that can be tuned by adjusting a screw instead of a clip and pin type!!...thanks dance1

old motorbike · Jul 16, 2009

I believe it's a 16mm bore. There are other more sophisticated carburetors out there and price goes up. Do a google search.
The clip needle is still being used in some m.cycles (that aren't fuel injected yet).
It's a simple system to set up, but mine, I had to also use a smaller jet also to run better.

motorhead419 · Jul 21, 2009

If I'm not mistaken the majority of the carbs are 13mm..

azbill · Jul 21, 2009

I have seen 16mm with a pic of the digital mic

motorhead419 · Jul 21, 2009

I just got out a new carb from a 80(66)cc kit and got 13.8mm..(.545 inches) I checked it twice. The slide is 14.5mm (.569) so the carb can't be 16mm....They do have the new style 80cc carb which is a little bigger and it has the fuel shut-off valve on the right side of the carb..

xlite · Jul 21, 2009

motorhead419 said:
I just got out a new carb from a 80(66)cc kit and got 13.8mm..(.545 inches) I checked it twice. The slide is 14.5mm (.569) so the carb can't be 16mm....They do have the new style 80cc carb which is a little bigger and it has the fuel shut-off valve on the right side of the carb..

I also get 14mm for the slide and AFAIK NT carbs have always had inlets on the right.

Jets on 4 of my 80cc were just narrowed and all of them ran smoother. No big increase in top speed but no roughness at WOT now.

motorhead419 · Jul 21, 2009

I know they have inlets on the right side ,but if you go to SPOOKYTOOTH you will see the new style 80cc carb with the shutoff valve right on the carb itself..It's the new style NT carb 66/80cc

motorhead419 · Jul 21, 2009

I'm trying to get a good used 18mm Mikuni...I had a new one on ebay in my grasp for $50.00 and let it go..They got other new ones for $65 + shipping. I'm just looking for a good $25.00 used one..I got plenty of Mikuni Jets and needles. So if anybody out there has a good used one give me a shout.

xlite · Jul 22, 2009

motorhead419 said:
I just got out a new carb from a 80(66)cc kit and got 13.8mm..(.545 inches) I checked it twice. The slide is 14.5mm (.569) so the carb can't be 16mm....They do have the new style 80cc carb which is a little bigger and it has the fuel shut-off valve on the right side of the carb..

Ahhh... I thought you meant as opposed to left side. Thanks for the tip. I've been waiting for an 80cc NT carb for years. It explains the 16mm comments too. I wonder what that screw is on the right side?

Spooky don't appear to sell parts. Anybody know where one might buy one of these new carbs?

motorhead419 · Jul 22, 2009

I just got one from spookytooth..and it isn't 3mm bigger as they say..I'll go remove it off my bike and measure it right now..The slide measures .589 (14.9mm) I couldn't go by my carb on the bore size because I've already reamed it out, but I'd say they are 14.6-7 mm, so you gain about 1mm in carb size. I taper bore them out for better flow. I just tried to download a pic but they said it was too big. Here's my email [email protected] I'll send you some pics of it. I'll sell it for the price I just paid for it if you're interested, because with my mods I really need a 18mm.

radrob · Jul 22, 2009

spooky tooth has 2 upgraded carbs to chose from. nt for $25 cns for $40

the $40 comes with throttle ,throttle cable ,and k & n style cone airfilter. has choke lever on handlebars. adj air fuel

xlite · Jul 22, 2009

motorhead419 said:
I just got one from spookytooth..and it isn't 3mm bigger as they say..I'll go remove it off my bike and measure it right now..The slide measures .589 (14.9mm) I couldn't go by my carb on the bore size because I've already reamed it out, but I'd say they are 14.6-7 mm, so you gain about 1mm in carb size. I taper bore them out for better flow. I just tried to download a pic but they said it was too big. Here's my email [email protected] I'll send you some pics of it. I'll sell it for the price I just paid for it if you're interested, because with my mods I really need a 18mm.

So maybe I'm back to square one if it's not really much bigger. I can't see any links for parts on Spookytooth site. Do you have a link to that carb?

Also the picture shows a screw on the right. What's that for?

motorhead419 · Jul 22, 2009

spookytoothcycles.com will get you there..The bolt with the phillips head in the middle is the fuel inlet. It fastens the little petcock to the carb

xlite · Jul 22, 2009

motorhead419 said:
spookytoothcycles.com will get you there..The bolt with the phillips head in the middle is the fuel inlet. It fastens the little petcock to the carb

Hey thanks. I needed to go back to the home page and find parts from there.

I thought the phillips might be for mixture. If it's really only 1mm bigger that don't seem a real improvement. Even 3mm sounds iffy. Maybe I should start eyeing those 18mm too.

bee187 · Dec 8, 2010

hi to all been reeading all ur tips 4 months now but only just joined so thanks heaps. now iv had 2 of these engines first one was **** from the start and died with in 3 months and sencond one is still going strong.i am currently playing around with different carbys atm iv got a 125 Mikuni carby on it and i must say it goes harder then ever b4 but when i pull up it doesnt seam to drop rpms for some reason,do you think its just to big of a carby,or maybe i could re jett it?

motorhead419 · Dec 8, 2010

What size is the Mikuni? I use a 18mm..Any bigger than that and you will hurt your performance..I got jets to help you tune it if necessary. .wee.

Nashville Kat · Dec 8, 2010

I measured the bore of the two NT cabs last week-

I'm talking about the opening itself, not the size of the mount, which is identical otherwise.

The old standard NT carb is 13mm
and the newer NT66 Speed carb is 14

1 mm larger opening just like adverstised- the jet is larger too they claim

the billet intake measures exactly 14 mm before extra reaming- My old one is reamed to 15mm
I have an old stock intake I'm not sure if I reamed or not that measures more like 15 on the opening-

It doesn't make sense to put a carb with a larger bore on an intake that still measures the same, the opening is still the same
except when, like the billet intake, it moves the carb closer to the motor-

that seems to make a big dif.

The billet really needs no extra reaming with a carb of 14mm bore, except on the engine side perhaps.

culvercityclassic · Dec 8, 2010

I have run both carbs and intakes and it's really down to how well you tune them. IMO

Ccc

motorhead419 · Dec 8, 2010

You have to use a Manic Mechanic (Jim) straight billet intake and open it up to get your bigger carb to work properly. xct2

Nashville Kat · Dec 8, 2010

Outside of the center rod notch, isn't the idle about all you can adjust on an NT carb?

The billet intake opening matches the newer bigger NT Speed carb- 14mm.
The billet's recently been shortened in length by 1/4" to get even closer to the motor and have more frame clearance behind- I got one for a 1/2 price song on Cyber Monday.

pictures: http://motorbicycling.com/f3/what-good-carb-25591-3.html

It works great with either carb, but I've just started the newer carb, and not really tested it.

carb size??

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