Carburetor differences

[BilalCarroll]

How much of a difference does the racing carb make compared to the stock like these:http://www.ebay.com/itm/222274601502
And how much of a difference do carbs like this make compared to a stock one:https://www.gasbike.net/collections...0-reed-valve-keihin-carburetor-clone-assembly

 

[Steve Best]

I have one of these carbs:

It makes no difference over the NT carb when both are tuned properly. Both are 14mm.
The stock NT carb is easy to jet and work on.

Some of those air filters have no gauze in them, they are just a screen and will not keep grit out.

This is a reed valve and larger carb:

I am going this route but you have to realize this is not a simple bolt on.
Much of the motor has to be modified to make use of the larger carb.
It will do nothing for a stock engine.

So to make use of a carb this large (16mm vs 14mm stock) you need much better porting and pipe.
Stick with your stock carb and learn to jet it.
Buy a set of jets and read about "Plug chop". Several jets from 68 to 62 should do it.

A tuned pipe will be needed before you need a carb.
You can double the stock hp even with the stock NT carb.

Steve

 

[BilalCarroll]

Steve i have another question. is the seal on the racing carb better than the stock because the seal on the stock one looked pretty s**t compared to the racing one. I thought it had a bad seal due to the fact with the NT i could not idle.

 

[crassius]

The NT style carb with the chinese chars at the top works well, and usually doesn't need any adjustments at all - all other carbs can be made to work with sufficient tuning effort, but seem no better for an unmodified motor.

 

[libranskeptic]

FYI folks, Wiki:

"The word carburetor comes from the French carbure meaning "carbide".[2] Carburer means to combine with carbon (compare also carburizing). In fuel chemistry, the term has the more specific meaning of increasing the carbon (and therefore energy) content of a fluid by mixing it with a volatile hydrocarbon."

 

[Frankenstein]

FYI folks, Wiki:

"The word carburetor comes from the French carbure meaning "carbide".[2] Carburer means to combine with carbon (compare also carburizing). In fuel chemistry, the term has the more specific meaning of increasing the carbon (and therefore energy) content of a fluid by mixing it with a volatile hydrocarbon."

Carburizing is different from carburation.. And that wiki article doesn't even sight a source for that info.

Carburation is the introduction of hydrocarbons into air or whatever the fuel happens to get oxygen from.

Apparently the design was so primitive at one time that the guy was using a wick (yeah a wick, basically whatever volatile fuel that could evaporate would give off enough fuel to run a small motor.)

Wikipedia isn't the best source of info. Honestly I don't believe a single person alive now actually knows why they picked the word carburetor, probably like the words Frisbee or chopsticks (have nothing to do with bees or chopping.)

Its possible that the guy had the foggiest clue about chemistry and figured that because he used his carburetor, vs some inefficient Drip or air passing over a pool of gas, he noticed it gave more power. At the time it may have been the only word that could describe what was happening even though it was wrong. We've seen that in history enough times to know it probably had nothing to do with what it was being called at the time.

Steve, you absolutely will not be disappointed by that carb and Reed set up, very very smooth and responsive all across the rpm range, you'll probably need different jets unless you already have the Dellorto idles and mains from a different carb. If you have trouble finding that big rubber tube should the stock be too short then head to a refrigeration supply place, the rubber high pressure hose used by many systems is fuel and oil proof, around here home Depot carries plenty of it.

 

[skyash]

Stock to racing carby not much top speed differences bit faster on take off but sounded much more smoother no more pop crack just a nice note up and down the revs like a real motorcycle.i also found the seal better to little o ring .but then it started to froth up the petrol in the fuel line then the tank then out the tank cap at full speed .i got that bigger carby to but can't get it tuned right no reed seems to have 2 jets idol and going I get one not the other keeps cutting out well trying to go lot of trouble just sits in a box now.

 

[Steve Best]

Just throwing random thoughts in:
I worked on old tractor and spray gear updraft carbs that had a pool of fuel to draw the air over. No Jets!
Mixture was set with float level. These Kemac wood stove oil burners work the same way:

This burner fits on the back of a kitchen wood stove.
Was very common around here when I was growing up.

I did some carburizing as a machinist in the early years of my career.
We either used a fuel rich flame to put a hard skin on red hot steel,
or put the item to be hardened in an oven in a box packed with coal, bone, or a special carbon compound.

 

[Frankenstein]

Just throwing random thoughts in:
I worked on old tractor and spray gear updraft carbs that had a pool of fuel to draw the air over. No Jets!
Mixture was set with float level. These Kemac wood stove oil burners work the same way:

This burner fits on the back of a kitchen wood stove.
Was very common around here when I was growing up.

I did some carburizing as a machinist in the early years of my career.
We either used a fuel rich flame to put a hard skin on red hot steel,
or put the item to be hardened in an oven in a box packed with coal, bone, or a special carbon compound.

Bingo buckeroo