Can we discuss Chinese carbies?

lrrs said:

The chinese knock off carb for my stihl weed wacker made it run like new again. 

I looked at those when rebuilding my in-laws Poulan chainsaw.  They got rave reviews on Amazon.  I might go back and get one.  Saw still doesn’t run right.

ShawnG said:

The reason most people think carburetors suck is because they have been taken apart and put back together improperly by people with the attitude of "it's just some metal with holes in it".

A watch is "just a can with gears in it"

Chasing a tuning issue that is caused by flawed castings or improperly drilled orifices will make you pull your hair out.

There's a reason the big names in carburetion are big names in the first place. They build a good product.

I've had bad experiences with parts store rebuilt carbs that gave massive bogs, stumbles, and all sorts of issues, and that's when somebody started with good quality castings and just didn't do a good job assembling and cleaning them. I'd hate to see what would happen if you also had a porous casting or serious core shift issues. A lawnmower or chainsaw is something I'd be a bit less scared of a cheap carb - both because you're out less money if the carb is a mistake, and because they have a much narrower operating range.

ShawnG said:

The reason most people think carburetors suck is because they have been taken apart and put back together improperly by people with the attitude of "it's just some metal with holes in it".

 

I'm confused. 

Carbs do suck.  That's exactly the physics work.   The Bernoulli effect lowers air pressure, which sucks fuel into the air stream.  All the holes do is control how much suckage there is in a carb.

Carbs have sucked since the dawn of carburetion.  

Fuel injection, on the other hand, blows....  

In reply to alfadriver :

Carbs don't suck.

Atmospheric pressure forces air into them to fill the vacuum left by the descending piston.

I thought you were an engineer type. 

In reply to ShawnG :

All depends on your perspective.  Fast moving air lowers pressure, thus sucking fuel into the air stream. 

Carbs suck.  

It all sucks. Just an endless cycle of suck, squeeze, bang, blow. Until something really blows.

Back on topic, I've used Chinese copies of little dirtbike carbs, weber copies, all sorts. The only carbs I've ever had trouble with are the ones that had been meddled with by people who shouldn't own tools.

Do it. Whats the worst that could happen?

I guess, as expected it's a crap shoot. Sounds like I could either end up with an awesome bargin or an ugly paperweight or anything in between.

As with a few others here, I've had fairly good experiences with small engine Chinese carburetors. But I can definitely see how a more complicated assembly has more margins for error.

I'd be fairly inclined to strip, clean and check everything prior to install. 

In reply to BlueInGreen - Jon :

I saw Chinese Crabbies.

interesting thread none the less. I think if you're building a go ped or something go for it, my husqvarna? hopefully never needs a new carb 

and carbs dont suck you just gotta find the one you like and deal with it. EFI is too costly. 

ShawnG said:

The reason most people think carburetors suck is because they have been taken apart and put back together improperly by people with the attitude of "it's just some metal with holes in it".

A watch is "just a can with gears in it"

Chasing a tuning issue that is caused by flawed castings or improperly drilled orifices will make you pull your hair out.

Ah, yes.

The nicest thing I can say about BG carbs is that, being aluminum, they are readily recyclable.  And they had some very good advertising back in the day.  But machining finish, emulsion quality?  Better off just sort of aiming the fuel pump outlet at the intake manifold and hope for the best.

I note that BG went out of business and Summit bought the rights to the name.  These are a different product, and I have no experience with them.

In reply to Stealthtercel :

I saw Chinese Carbines...

Appleseed said:

Chinese carbs? Hell just ask about how good Demon carbs were. 

Had to check to make sure this wasn't a zombie thread and I read one of my own replies.

BTW, by machining finish, I mean things like adjusting float height would tear the needle and seat's O-ring and cause it to flood out.  Had to take a cross-buff and clean out all three carbs (because of course it had to be 3x2s).  And they'd still tear on occasion.  So you have to ask yourself, if there is a problem with sharp edges and burrs in that bore, what do the metering circuits look like?  And keep in mind that Holley jets are sized by flow, not inside diameter.  Three consecutive jet sizes may have the same ID but different edges to the hole.

It was still kind of fascinating in a way.  Dyno tuning outdoors at night, you could SEE the fog of fuel hovering an inch over the end carbs because of standoff due to the irregular V8 firing order.  But, it just HAD to be 3x2s.

frenchyd said:

TurnerX19 said:

Bernouli's theory is a myth, get fuel injection by some means.

Some of us have plenty of experience with carbs. Virtually none with FI. 

While I covet the ease I see you young whipper snappers “tune” your engines by plugging in a lap top. Changing jets, chokes, accelerator pumps just seems easier.  

Actually how hard is it to start from scratch with something that doesn’t have a program written for it?  

Say you wanted to do a 1927 speed 6 Blower Bentley or an MGB?  

While I know modern EFI setups are getting to this point, basically you can put a carb on something, give it fuel and spark, and it will run. That simplicity alone keeps me in the carb realm. I'm never going to have an issue with a sensor or a bad circuit that won't let my car run. Will it ever run as perfect as EFI? Probably not. But it will run basically come hell or water.

Back on topic, my brother bought some Chinese carbs for his bike, and they worked OK. If I remember right he had some minor issues with one but was able to figure it out.

Chinese carbines are actually very good.  They even sell at a premium to other carbines, such as those from East Europe.

Dr. Hess said:

Chinese carbines are actually very good.  They even sell at a premium to other carbines, such as those from East Europe.

Particularly the SKS branded variety.

For small engines I've had good success.  For the price of a rebuild kit, it's plug and play.  Although, I hang on to the original, and rebuild at my leisure.

I've heard that some of these are made side by side with oe carbs. Mostly the stuff on small displacement Japanese bikes. A quad I recently purchased had a clone carb. Was running poorly at idle so I removed it and the float level was off, according to the manual.  So I set it at the correct height. So, of course, it wouldn't run. Best part is that it's a massive pain to pull and adjust. Thanks Artic Cat. Oh, and no guarantee that a new one is better as the dealer mat end up selling ypu a Chinese carb for 10xs the price. 

On the flip side,  they sell a 40 dcoe for about $150. It looks so identical. If that isn't tempting...

In reply to daeman :

Are we talking about several carbs or one?  
   If several,  yes it will be a problem tuning if they aren't identical.

  If you are patient you can correct them•••••• If you are patient and can tune, actually tune, not go by numbers.  
     The goal is to put fuel and air in the right proportion into the manifold. 

  Take the carb/s apart. Then using a numbered drill bit set  figure out what number a hole is.  Then check the other carb and if it's the same size. You win. If not you've got to decide which one is right.   Checking a pair of Webers should take about a 1/2 hour. 3? An hour.  more? Add a lot more time. 
    If when finished  you'll need to buy a ream for each hole that differs.  Nope you cannot use a drill bit. They actually don't drill round holes so flow will vary too much. 
     If you need to have the carb correct out of the box. Don't do it.  
If you like putting together hard puzzles?  And the savings are worth it. Go for it. 

In reply to 02Pilot :

Yep.....ask me how I know.

I have bought more cheapo Chinese carbs than i can remember.  I frequently do small engine work and i can buy a whole new carb for cheaper than a carb kit and a can of carb cleaner.  If im starting with a new project, im usually just grabbing a new     cheap carb to start with. 
 

also, the best part is the Chinese carbs usually arent "sealed" for CA emissions, so instead of the thing running like crap and too lean to meet the requirements of people who have ZERO concept of how engines work, you can actually adjust the air/fuel mix to make the motor run smooth and perform better. 
 

just make sure to compare the jet sizes. The carb body may be a perfect match but sometimes the jets are different. In that case just swap your old jet in. Or go to your big bag of assorted cheapo Chinese carburetor jets and adjust accordingly. 
 

for the really small webber stile carbs like sub 50cc stuff, frequently they need fuel lines and a fuel metering diaphragm. I bought a pile of metering diaphragms for dirt cheap. Good ol' cheapo chinese stuffs from Amazoni-baba. 

Carbs are just toilets for fuel. Change my mind. 

I like carbs. I enjoy working on them, and I'm generally successful getting them to work. But, I met my match with the 1bbl FoMoCo/Autolite POS on my six cylinder Falcon. These carbs have a bad reputation, and it's not undeserved. I won't go into why that is. But, let one sit around for a dozen years in a damp environment and no amount of soaking in an ultrasonic will "bring her back around".  I just could NOT get the car to run right.

So, I bought a Chinesium Hankyo carb off Amazon with trepidation.  I did a lot of reading about them prior to purchase and most of the problems seemed to stem from them not being set correctly (float height, mixture screws) out of the box. Some suffered from leftover swarf. One or two reviewers claimed poor casting or machining. I took mine slightly apart and checked everything before installation. It was all set properly and looked good. Bolted it on the engine and, for the first time ever in my ownership, the car would actually idle. In short, it works perfectly. And only for the equivalent price of two rebuild kits. 

So, if they can make one of these gawdawful carbs work out of the box I wouldn't be afraid to try some other types.

ddavidv said:

Carbs are just toilets for fuel. Change my mind. 

Carbs are perfume atomizers for fuel.  They mix the fuel with air before it is even allowed into the airstream, so the engine sees a well prepared combustible fog.

EFI is the toilet.  It just dumps fuel when you flush it, no atomization.

This is a good chunk of why nobody has ever been able to get an engine to make more power with fuel injection than a carb on a dyno.  You can get much better drivability but you cannot make more peak power.

Note that F1 engines spray the fuel UP into the plenum and not down into the ports, and I don't know if they still do, but they used to preheat the fuel and inject at super high pressures to maximize atomization.

So, if they can make one of these gawdawful carbs work out of the box I wouldn't be afraid to try some other types.

I have heard bad things about the DCOE type carbs.

Maybe the difference is that casting imperfections don't matter/aren't noticeable when it's a single barrel feeding a lawnmower or whatever, but you stick two two-barrel carbs that need to be synchronized on the engine, all bets are off?

Pete. (l33t FS) said:

I have heard bad things about the DCOE type carbs.

Maybe the difference is that casting imperfections don't matter/aren't noticeable when it's a single barrel feeding a lawnmower or whatever, but you stick two two-barrel carbs that need to be synchronized on the engine, all bets are off?

I have too, but your phrasing here is now making me wonder how much is the fault of the carbs, and how much is the fault of the people trying to make them work. I've been dealing with DCOEs (real Italian ones) for decades, I have the necessary tools, and I still feel like there's some level of voodoo necessary to get them really right.

I always look to see if the repro I'm buying has a website separate from the Amazon/eBay listing. If they do, the likelyhood they're good quality increases quite a bit but it's not a shoe-in.

A local amazon reseller has funky rando carbs in it all the time, always for scooters and lawnmowers. I have a few spares now for stuff I own (though question if it works!) and a drawer of random carbs now just in case 

02Pilot said:

Pete. (l33t FS) said:

I have heard bad things about the DCOE type carbs.

Maybe the difference is that casting imperfections don't matter/aren't noticeable when it's a single barrel feeding a lawnmower or whatever, but you stick two two-barrel carbs that need to be synchronized on the engine, all bets are off?

I have too, but your phrasing here is now making me wonder how much is the fault of the carbs, and how much is the fault of the people trying to make them work. I've been dealing with DCOEs (real Italian ones) for decades, I have the necessary tools, and I still feel like there's some level of voodoo necessary to get them really right.

I have to Second that.  Carbs have been. 99% of my experience  and over the decades I've corrected more than a few "experts"  work  in that regard.
1. Guys who assume the numbers are always going to be right. Never realizing  that different cylinders may have different vacuum levels or that the different curves/ lengths in the intake tract doesn't change things. 
                          OR

2. Are inept or lazy or careless about synchronizing  the carbs. 
                            OR

3.  Working from a box of jets , air correction meters, etc that include some that have been modified. 
  I always used to look with a big magnifying glass and bright light before I'd return something to my cabinet.  Look for signs that they've been modified. 
                           

In reply to 02Pilot :

That is a valid point, but I have heard it from people who had previously successfully tuned Webers.  

Weber tuning on a rotary is especially fun because you need to modify your emulsion tubes, since Racing Beat does not sell them anymore.  I would expect a rotary-specific carb guy to be well versed in exactly what each circuit does and what changes to make to gain a certain effect.