Looking for a good carb

F

fischer550

Member
So reading on this forum, seems like the NT is a good carb for STOCK engines, however, I may be wrong but I would consider my engine heavily modified.

-Stock bottom end
- Ported and decked cylinder
- torquer pipe from arrow
- fred head
- boost intake from fred
-piston cut

So, AFTER BREAK IN, I want to get a better carb. I live at 6,500 ft above sea level. I preferably want something thats very easily tunable and adjusted, but am leaning against walbro because I would have to take off my fred intake. If I could just slap it on the fred intake (which is stock size diameter), that would be best. Thoughts? (Note: I'm willing to drop the money on something pricey)
 
With a STOCK diameter intake, a carb change is useless for more power.
Others will argue different, but you can only get so much air through a pinhole.
The NT is cheap, stone simple and easy to tune.
Not true of almost ANY other "performance" carb.
 
I agree, the stock NT will do just fine even on a modified engine... There are a lot of sellers who like to call their carbs "performance carbs" when they're nothing but a different carb for a different application, then they don't tel you that in order to get them working you'll be going crazy trying to figure out the jetting, needle settings, fixing air leaks because they don't fit our manifolds, and the list goes on... they just get them cheap, call them performance parts and mark up the price, and they could care less if you get it running right or not...
 
I can actually order a bigger diameter intake from fred. That being said, any ideas? I heard about the mikuni 18mm but some say it's too big for the motor.
 
stick with the NT or the RT carb in my opinion, Jake's sells an 18mm Mikuni and he has the intake for it, he runs them on his bikes but those type carbs are not for the noob, to get them set up right there are multiple things that have to be change or tweaked.

The NT carbs and the RT carbs work great on a modified china girl engine, some even have good results with the CNS carbs which I plan to tinker with a little in the future myself, but honestly good power and good top speeds can be had with the simple little NT or RT carbs, my fastest top speed was on a bike running an RT carb, the engine has several mods and with that little carb I GPS'd 50.3 mph I have another bike with less mods and Im running the NT Speed carb on it and it cruises nice in the low 40's and pulls a 36T rear sprocket with my 200+lbs on it just fine.

beware of the snake oil out there... lots of it and some of us can teztify to it because we have been there done that and tried some of the fluff stuff just to find out that those dollars could have been better spent somehwere else.

bottom line is that if your looking to have a good strong bike that will cruise in the 30's all the way up to the low to mid 40's, the little NT or RT will both be plenty of carb to do that for ya and as it has already been said by other very knowledgable people here, these carbs are simple to tune and very reliable and like the old saying goes" if it ain't broke, don't fix it ".

map
 
fischer550 said:
I can actually order a bigger diameter intake from fred. That being said, any ideas? I heard about the mikuni 18mm but some say it's too big for the motor.
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Some are just plain wrong about that and prolly don't have carby concepts down well enough In My Experiance. I just wanted to get this across.

At my very high elevation I use a 21mm on a 49cc Morini engine. Works absolutly flawlessly and I would do it again in a heartbeat , knowing what I know now. Dang carb is almost the size of my piston! Here is the deal tho like Dave said. Your the one stuck trying to tune it. I was on my own lol. I had to read charts etc and learn! It sucked for a while man. Finally got it as I would simply not give up!

Took me awhile 21mm Dellorto. What I walked away from learning wise. Not so bad at all with good ol 20/20 hind sight..

These folks suggesting a RT or NT carb are giving you a very very easy and simple way out! Yes these carbs are very forgiving tune wise.


The bigger carby gave me more power and RPM's. A better seat of the paints feel. ''After taming'' Not confused at all about this!

Any of them ''some folks that are saying'' if they are near sea level? Well it gets even easier to simply slap a big carby on! The game is air. I have at least 4 freinds here with H.T. engines that have 19,20,21 size carbs at 6000 feet. Two of those were used carbs resurected from a small engine shop of the likes of some old engine. Would not recommend any biger than 21mm tho.

After carb tuning 101, they all run perfect...Some carbs were easy other nearly seamed impossible. In the end they were ''''''all''''' possible. We have intake manafolds to match...

This is mandatory to me as of now. ''Sea level I am not'' Would love to try out some thicker air at sea level. My best high speed runs here at altitude has been in the winter with more dense air.

A big carb is just not a Newbee type suggestion. There are implications to tuning. Running too lean or rich. Knowing what to do to a carby to correct that. How the carb works through the entire power band and Idle circuit is a pita as well. It is a edjumacation most folks may not understand or ever be able to fix.

Folks that say it cannot be done don't know what they are saying in my humble opinion. Cuzz I got'em running just fine!!! Every carby a learning curve in it's own right.

Those little RT NT carbs have itty bitty tiny float bowls and somtimes you get a lemon. One where the needle float assembly is a bad omen. It may leak somtimes and somtimes not. My bigger carbs have a bigger float set up. So they have a float with enough ''float power'' to shut the float bowl needle off. This alone makes me happy.

I had a NT for over 8000 miles. That float bowl ALWAYS HAD A ATTITUDE.

When I worked in a small engine shop the crappy tiny chinese carbs and them tiny float assemblies were a joke at times. I would have done a tune up everything flawless, perfect no gas dripping or anything. Go to deleiver it and the float bowl was flooded. This of course could happen with any carby big or small.

Bottom line none of this stuff works unless you have the patients and understanding to match...

You know that little bit of ump that comes from port matching? Do it with a bigger carb is my motto.

Like Manic said what good is a carby being fed through a pin hole lol. All that porting for nuttun. laff laff

All this said if you don't have a clue get what these folks are suggesting to you... Smaller carb
 
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The bigger carbs are fine for the experienced but not for a newbie, when I can build a china girl and get good power and high 40's to a max top speed of 50 mph using the small Dellorto Clone "RT" carb, I know I can honestly and safely say that it will easily do all the biggest majority of china girl owners will ever need.

Yes a well ported and correctly set up engine can benefit from a larger carb if the engine is set up to handle it, if things aren't done right its like putting a Holley 1050cfm Dominator on a 9.0:1 compression 283cid small block Chevy that has a little RV cam grind and some small 1 1/2" tube headers and 2:73 gears in the Differential.

Some people have been fighting serious battles from the get go just trying to get their bike going to the point of being able to keep it running and having enough reliability to go 3-4 miles and back, so the last thing I aim to do is to suggest in any way that they should go down another road filled with what will certainly be a big barrel of more trouble for them like using a carb that requires a lot of know how and experience to ever get going right.

Just my honest opinion on the big carb vs keep it simple st.... carb like the NT and the RT, personally I like the NT carbs better for the most trouble free and ease of tuning that they provide, and they give good performance all the way into the mid to possibly upper 40's MPH range if all else is capable of doing it.

map
 
mapbike said:
The bigger carbs are fine for the experienced but not for a newbie, when I can build a china girl and get good power and high 40's to a max top speed of 50 mph using the small Dellorto Clone "RT" carb, I know I can honestly and safely say that it will easily do all the biggest majority of china girl owners will ever need.

Yes a well ported and correctly set up engine can benefit from a larger carb if the engine is set up to handle it, if things aren't done right its like putting a Holley 1050cfm Dominator on a 9.0:1 compression 283cid small block Chevy that has a little RV cam grind and some small 1 1/2" tube headers and 2:73 gears in the Differential.

Some people have been fighting serious battles from the get go just trying to get their bike going to the point of being able to keep it running and having enough reliability to go 3-4 miles and back, so the last thing I aim to do is to suggest in any way that they should go down another road filled with what will certainly be a big barrel of more trouble for them like using a carb that requires a lot of know how and experience to ever get going right.

Just my honest opinion on the big carb vs keep it simple st.... carb like the NT and the RT, personally I like the NT carbs better for the most trouble free and ease of tuning that they provide, and they give good performance all the way into the mid to possibly upper 40's MPH range if all else is capable of doing it.

map
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I can get to 50 mph long before you can every single time with my set up. Waiting a long time to go 50 mph is not my forte or very exciting IMHO . I like the power I have from stop to go BIG TIME. No Happy time with a little carby 1/3 the size will ever compare to that. Thats a straight up fact jack!!

Wanna race?dnut

As for these fragile peice of work near garbage HT engines. Don't do anything to them and above all don't hotrod them. They fall apart to easy. I have to agree with Map there. Where this conversation is going? It can very hard to give advice with less than optimal equipment.

As for my personel favorite Morini 49cc. I got some 20,000 miles on it and still have cross hatch in the bore. Top to bottom. I beat the bujeebers out of this thing constantly . Gotta imagine being the quickest kid on the block no matter what. Ayup! Undefeated too. Funny thing tho that engine lives for it. ''morini'' It runs flawless to this day.


As for what the top dogs at the California races are doing at a professional race track? The top dogs are not doing it with little bitty carbys. Confident I can say that lol.laff

Now back to these carbys mine, all of mine idle perfectly. They do the rest in spades as well.

I will always get to fiddy faster than you can Map with my Uber Kewl carby. Nana Nana Nana boo B00

We already played barrio competition over here a long time ago. I am ready for anything! The kids here gave up trying against me a long time ago.

Change of gears and I can do sixty and more any time I want. About 40 mph max for me and a lot of power to go with it too. This means around the block quicker than the rest.


Now one of my little Morini 49cc engines came with a Dellorto Clone syle AKA "RT". I don't use them for a reason......at the time I was doing everything I could to not have it running any way near like some generic H.T. laff It would have run that way fine prolly forever . Yet for me why bother. No HT can touch this............

There was nothng wrong with it . I mean it ran good.

That motor was happy with it. No where near the power I have now tho. I am only speaking from experience and only ever will..

Wanna keep it simple? By all means put a little carby on it. Want to be the quickest down the block well??

My old ''stock'' little Volks Wagon could do 100 mph. Have to wait a long dang time to do it too. Gee Guess I could nonchalantly say my Car is the fastest thing ever!! lollaff ''NOT'' wanna race? I get so tired of reading about stuff that is so wrong.... Sombody wants to know the best way to get power and then the opinions start poring in. All I wanna do is clearly say whay a bigger carby is better.

I have to agree with Map however. As difficult as these words are to convey. Put a small carby and ride it. If you get smarter about what you are doing and get to know how things work. Only then try somthing differant. We got folks here that barely know what a carb even is..serously.


Mod a motor or halfway mod a motor. I go ALL the way myself. Somtimes that can bite a fella?

I do feel sorry for some newbees here. Every time a Happy Time motor falls apart.

How many H.T. motors you break Map. I lost count myself.. Mebbe the speed limit should be about 25 mph lol? You got after market bearings and everything by now aye?

Oh yeah wanna race? When you get to fiddy I will be that small dot over the Horizon. ''way up in front of you'' Ayup...................................

I am so glad I got a real Motor at one time. I would still be preaching and parroting H.T. happy time wise tells myths and even making them up by now. Got to debunk the garbage at some point. That my freind really truly was a blessing for me. I honestly would not know what I do now.

Oh yeah they don't run little bitty carbys at the race track!! Not the clear winners anyway. Just thought the OP deserved to know that!!! Last don't put a nice carby of any kind on and have a lousy over restricted air filter ether...LOL
 
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GHerder, this fella tha is asking about carbs here wasnt asking anything about a Morini Engine, doesn't have a Morini Engine, has made no claims here that has wants a Morini Engine, so Honstly I dont understand why this conversation has been take to the Morinin side of the spectrum....lol

I not mentioned the Morini Engine and I never compared the China Girl to a Morini Engine, I never made any claims about a China Girl being better in anything way, never made claims of the China girl being more reliable in any way than a Morini Engine, for that matter some they will read this thread have never heard of a Morini Engine.

Now all that said, do you see anywhere that I have ever compared a Morini in any way to a China Girl / HT engine?

answer: Nope!

I understand that you are a dyed in the wool Morini fan here and think that the HT isnt worth beans, I dont have a problem with that, yep when it comes to building the little HT for running high RPMs for fairly long periods they just dont typically hold up for long, it is best to build them for comfortable cruise speeds in that upper 20's to low 30's and if the engine has a fairly so so balanced lower and the crank bearings are good along with using a quality upper bearing they can run reliably and dependable for several thousand miles, I know because I have done it and several others on here have done that also as you already know.

Comparing overall longevity and performance of a Morini or any other medium to high quality engine to the HT isn't comparing apples to apples at all, I know that and you know that, why come on this thread hating on the HT engine and then giving all the rant on how mu h better the Morini is when that is miles away from whT the original question by the OP was or is, the HT engines do good when set up to run within their cabability, and when you push them beyound that for very long they will give up on you pretty quick, been there done that, we have no disagreement there, but since we got off on the rabbit trail of not comparing apples to apples, how about we do that race you challenged me too, and Ill be on my 1584cc Fuel Injected Harley Davidson and you on your Morini powered bicycle, heck Ill even drop down and ride my 1982 Yamaha XJ650 Maxim to make it more fair....lol...!

seriously, I think the Morini powered bikes are awesome, I have always liked them and never for a minute though an HT could hold a candle to them in reliability or performance, you are completely spot on and completely correct in all you said about the matter in my opinion also, but...... wenaint talking Morlni's here my friend.....w talking HT China-Lume disposable engines here and how best to set a good performing carb up on tham that aint a nightmare for a noob and will allow the engine to provide good performance and ease of use... these were my points and they are directed at the OP's actaul questions.

thanks for the imput Goat Herder, I respect your opinions on the Morini Engines and I dont disagree with you a bit, but we aint talking Morini's and no one is comparing the HT china girl to one of them either.

peace bro.....
map
 
I say use an NT carb, drill holes in the air filter box, and drill out the jet if necessary. Also ditch the boost intake. The china girl engines don't make enough vacuum pressure for the boost bottle to do what it's designed for. It's a gimmick. Disconnect the hose, undo the boost nipple, and either solder that hole shut or epoxy it with something fuel-proof. JB weld or seal all works. Or just get a new intake.
 
mapbike said:
GHerder, this fella tha is asking about carbs here wasnt asking anything about a Morini Engine, doesn't have a Morini Engine, has made no claims here that has wants a Morini Engine, so Honstly I dont understand why this conversation has been take to the Morinin side of the spectrum....lol

I not mentioned the Morini Engine and I never compared the China Girl to a Morini Engine, I never made any claims about a China Girl being better in anything way, never made claims of the China girl being more reliable in any way than a Morini Engine, for that matter some they will read this thread have never heard of a Morini Engine.

Now all that said, do you see anywhere that I have ever compared a Morini in any way to a China Girl / HT engine?

answer: Nope!

I understand that you are a dyed in the wool Morini fan here and think that the HT isnt worth beans, I dont have a problem with that, yep when it comes to building the little HT for running high RPMs for fairly long periods they just dont typically hold up for long, it is best to build them for comfortable cruise speeds in that upper 20's to low 30's and if the engine has a fairly so so balanced lower and the crank bearings are good along with using a quality upper bearing they can run reliably and dependable for several thousand miles, I know because I have done it and several others on here have done that also as you already know.

Comparing overall longevity and performance of a Morini or any other medium to high quality engine to the HT isn't comparing apples to apples at all, I know that and you know that, why come on this thread hating on the HT engine and then giving all the rant on how mu h better the Morini is when that is miles away from whT the original question by the OP was or is, the HT engines do good when set up to run within their cabability, and when you push them beyound that for very long they will give up on you pretty quick, been there done that, we have no disagreement there, but since we got off on the rabbit trail of not comparing apples to apples, how about we do that race you challenged me too, and Ill be on my 1584cc Fuel Injected Harley Davidson and you on your Morini powered bicycle, heck Ill even drop down and ride my 1982 Yamaha XJ650 Maxim to make it more fair....lol...!

seriously, I think the Morini powered bikes are awesome, I have always liked them and never for a minute though an HT could hold a candle to them in reliability or performance, you are completely spot on and completely correct in all you said about the matter in my opinion also, but...... wenaint talking Morlni's here my friend.....w talking HT China-Lume disposable engines here and how best to set a good performing carb up on tham that aint a nightmare for a noob and will allow the engine to provide good performance and ease of use... these were my points and they are directed at the OP's actaul questions.

thanks for the imput Goat Herder, I respect your opinions on the Morini Engines and I dont disagree with you a bit, but we aint talking Morini's and no one is comparing the HT china girl to one of them either.

peace bro.....
map
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Ok we also had big carbs on a H.T. motor in my neck of the woods. I said that.. However Apples to oranges will show ''and yes I can see I left that out'' that if a Motor as tiny as mine. The piston is like half the size of a typical H.T. Right there says to me that H.T. has breathing room!

Why not let the H.T. breath and run full abroad! Let it be a nice sleeper motor is what I am saying. I can ''cruise'' My bike and H.T. motors alike. Its when ya turn them on that's all I Am saying.. Every time H.T. stuff like this comes up I am like dang man let it breath!

Oh well I can see this is getting no where shrug.

As for input I study these H.T. motors pretty closely. As for how many got broke around me it was sad. Friends and I.

I know these little motors can be cleaned up. You have done it. I wanna know how far you can reach with it.. Light it up.

I am perhaps more destructive over here lol.
 
Goat Herder said:
Ok we also had big carbs on a H.T. motor in my neck of the woods. I said that.. However Apples to oranges will show ''and yes I can see I left that out'' that if a Motor as tiny as mine. The piston is like half the size of a typical H.T. Right there says to me that H.T. has breathing room!

Why not let the H.T. breath and run full abroad! Let it be a nice sleeper motor is what I am saying. I can ''cruise'' My bike and H.T. motors alike. Its when ya turn them on that's all I Am saying.. Every time H.T. stuff like this comes up I am like dang man let it breath!

Oh well I can see this is getting no where shrug.

As for input I study these H.T. motors pretty closely. As for how many got broke around me it was sad. Friends and I.

I know these little motors can be cleaned up. You have done it. I wanna know how far you can reach with it.. Light it up.

I am perhaps more destructive over here lol.
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right on.....! Goat Herder, they do break let crazy and I have had a couple bad ones and the latest casualty has been my fastes HT, I over did it when I lightened the piston and actually created a serius inbalance in the upper mid rpms low was smooth and very high was smooth but mid was like someone cut loose with a hammer in the engine, I thought it may have been the crank in that particular engine but is wasn't, I can see now that I had actually remove to much weight from the piston it seems and that was the serious mid vibe problem or at least that is what Im thinking for now, I put thatnsame upper on another brand new dax lower and the vibe issue was identically in the same rpm range, next Im gonna pull that jug, lightly hone it and put a new underilled piston and rings in it and see what the reults are, this should tell me for sure if the piston being to light was the difference in vibes in that rpm range.

yes they die easy, kinda like the old saying about sheep, always just looking for a place to die...lol!

now back to the carb stuff.

peace GH

map
 
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Goat, I have to ask you, sir, if you are so inclined to believe the HT will self destruct prematurely and they aren't worth the powder to blow them up, why are you advocating ways of making them turn faster? Seems to me your advice should be to keep them stock and get the most from them as opposed to trying to see how soon you can destroy one. Just my observation from reading this thread.

Tom
 
You got a good point 2 Door. I wanna clean one more of them up tho. It is going be a nonstock jug when I do I think. The crank is gonna be Mad Sceince over here lol Still making up my mind.

The reason I bring up the likes of what I have is because it can be compared to yes. However why not get the power availible from one of these things. The quistion I will always ask myself. Its a curse *shrug*. These little motors are not going away why not improove them?
 
Goat Herder said:
You got a good point 2 Door. I wanna clean one more of them up tho. It is going be a nonstock jug when I do I think. The crank is gonna be Mad Sceince over here lol Still making up my mind.

The reason I bring up the likes of what I have is because it can be compared to yes. However why not get the power availible from one of these things. The quistion I will always ask myself. Its a curse *shrug*. These little motors are not going away why not improove them?
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" why not improve them " is subject to what each of us feel is an improvement.

I know what you mean though, Arrow has made serious improvements and those have been thested and proven to get good power, speed and reliability from the HT, Fred has been working with his engines alot and has made several improvements that seem to also be good for more power, speed and should translate into better reliability because of the good balnce of the lower mecahnics.

most people that find this forum and want to get a bike built up dont have $1500 to sink into a bike and are looking for as much as they can get on what is a tight and limited budget many times, and for this reason I think it is the wrong direction to point them when we start all the big major mods talk, like port timing corrections and big honking carbs they will most likely never make work and a whole bunch more of he gadgets and gizmos we see spomen of on here all the time.

seems to me the bestnservice we can provide these people is solid simple advise on the little things that dont cost an arm and a leg that they can do to add to the ease of operation and reliability of their little china girl engine and bike as a whole.

we should in my opinion point them towarx realistic expectations for whT they have and discourage all the hot rodding mentality that we see on here, that stuff has its ace and I enjoy it too, but noobs with simple trouble shooting questions on their new builds shouldn't be hit with both barrels constantly with all the high tech hoopla from high performance crowd.

All that will do in frustrate and onfuse many people are give the pie in the sky ambitions that they dont have the tools or the know how to ever get done.

map
 
.....and some of us have this frame of mind....

I could have a Porche if I so desired. However, I would be happier with a plain, simple VW Super Beetle. Same basic design. One's sexy and fast. The other is simple, slow, and brings a smile to everyone's face. Not to mention, I can do all the work on the Beetle.

Or, maybe I'm just quirky!
 
Goat Herder said:
Why not walk some folks through ''all'' their alteratives with out arguing. Then they could make up their mindslafflafflaff
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Sad, but true......many people go through life wanting others to tell them what to do/get. This way, there's someone else to blame if it doesn't work out for them.

This isn't directed towards anyone here, but it is one of my observances in life.
 
Pretty sure I am part Rebel in that regard. Mebbe a Rebel with out a clue? I just know I got to keep moving! There are those scary conditions in life that get all our attention. Almost like when papa gets the belt.lol Ain't it always that way??:D

I try to use my secrete super sofa powers for good!

underdog.jpg
 
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