Carburetor Diferences

Is there a difference in a 2 stroke and 4 stroke carb?...I mean, mya I use a KOSO 28 m.m. cab on a 4 stroke mina, air looled engine?

Thanks!

Aloha, Mexicano. they are totally different. You may get it to run, but jets and needle will be out of whack. Especially the needle will be far too rich that it is not worth the trouble. frank

mikuni makes carberators for 4T and 2T they are excectly the same.
sow i think it wil run well. check mikuni site's or keihin. they have planty of information.

Beunos Dias Mexicano,
I just repaired a 1982 Honda XR80 (4 stroke) this past weekend. It had a Keihin carb that was no different than any other 14-19mm Keihin carb that I've seen on 2 strokes. It did have a peculiar manual choke mechanism, but irrevelant to tuning.
Some 4 stroke carbs have a vacuum diaphragm built into the carb, but upon a little inspection you will spot it.

scootertrog

Aloha, you can take a carb off a Ford Escort if you want and make it work, but why mess this way? Just buy a proper carb as they are cheap and will save you lots of headache time. The only thing 4t and 2t carbs have in common is that they have venturis and jets and use gas. frank

Thanks to all guys!

four strokes have more suction and this causes them to be able to get more hp out of a smaller venturi

the higher intake air velocity this generates will usually need re-jetting

also ,for cold starts, a two stroke carb usually has a fuel enrichment device, unlike a 4t carb which will have a "proper" choke in the form of a butterfly valve

Mexicano said:

Is there a difference in a 2 stroke and 4 stroke carb?...I mean, mya I use a KOSO 28 m.m. cab on a 4 stroke mina, air looled engine?

Thanks!

Click to expand...

Yes and no! Usually the carbs are the same, but 4-stroke engines are more sensitive when you pull the throttle or accelrate. So in a real 4-stroke carburettor there is an accelrator mechanism (the accelrator pump enriches the mixture). This mechanism can be electronic or mechanic) or in the other case you do not pull directly the throttle, but a diaphragm moves it.

There are universal carburettors they are even good for 2-stroke and 4-stoke engines. Usually they haven't got independet starting circuit but a butterfly valve in the venturi (you can enrich the fuel by closing the air path).
You can find very simple carburettors (without any extra parts) in a lot of small displacement (50-150-200cc) 4-stroke bikes.
In some case you cannot adjust a 2-stroke carburettor for a 4-stroke engine, cause it has a very different fuel metering system, for example the needle profile the needle jet etc.. is only good for 2-stroke, you have to replace them.

A the Koso carbs are good for 4-stoke engines. The manufacturer recommeds for 4-stroke engines too. You can easily adjust it for you 4-stroke bike! (I used the Koso 28mm carburettor for my 125 cc 4-stroke too without any problem).