250sx is the worst placed carb in the world. What’s a good Chinese replacement???

[kilabeez0]

Spent 3 hours taking off the carb and cleaning it as it’s sat with bad gas. Finally got it all back together and the sticky choke cable functioning properly. Started on first kick. Only problem is it only runs with the choke on. I can’t believe there’s no air/fuel mixture screws. Every time I have to take this apart and clean or rebuild it it’s an absolute nightmare. What’s a good Chinese replacement from eBay? After 35 years I’m ready to just throw another one at it rather than mess with rebuilding and having to hone the choke bore etc.

[Gabriel]

Good Chinese replacement? You'd have better luck finding an honest liberal democrat.

Sometimes you get lucky but most of the time (in my limited experience) you end up trading one headache for another.

[kilabeez0]

Ugh really? I’ll rebuild it if I have to. I feel like I rebuild this every 18 months or so. Granted this was gummed up and was green inside a bit.. but I ran it through my ultrasonic cleaner like 8-10 times for an hour easy. I’ve had this happen before, take it all apart and clean it, reassemble and it only runs on choke. I think one time I even had the jets reversed in it ��. I’ll have to go back and read my old threads. Still, getting this thing off is a nightmare and getting these hard rubber 35 year old boots to line up is just as bad.

[kilabeez0]

Ugh really? I’ll rebuild it if I have to. I feel like I rebuild this every 18 months or so. Granted this was gummed up and was green inside a bit.. but I ran it through my ultrasonic cleaner like 8-10 times for an hour easy. I’ve had this happen before, take it all apart and clean it, reassemble and it only runs on choke. I think one time I even had the jets reversed in it ��. I’ll have to go back and read my old threads. Still, getting this thing off is a nightmare and getting these hard rubber 35 year old boots to line up is just as bad.....


Edit: just did a search and I made this exact thread April 2017 ��. Consensus was to send mine to flyingVW and buy one from him.

[350for350]

I'd still say the same thing.

[ps2fixer]

Yea have flyingw rebuild it for you. Ultra sonic cleaners don't do everything, there could still be a passage blocked, a jet plugged etc.

The rubber from the carb to air box must be really stiff on your machine. It only takes me around 30 mins to get the carb out, and probably 30-45 mins to get it back in, unless you're counting the cleaning time too.

If you do end up replacing it, I'd buy the "junk" one if it's fairly cheap + shipping. I have a 250es that acts like it has an air leak, might be a crack in the housing somewhere or something, just haven't found the cause yet. (Runs normal, but when warmed up the tuning changes to be a bit lean with stock jetting etc, my other 3 or so 250sx/es machines don't have this effect). Figured between the two I should be able to make one good carb.

Either way, good luck on the repair.

Also a small side note, if you run pump gas there's 10% ethanol in it, pretty sure these machines were not designed to deal with ethanol in the gas, so at a bare minimum I'd suggest to always turn the gas valve off and run the carb out of fuel if the machine is to sit for a few days or longer. Better option is to buy ethanol free fuel but it's about $1 more per gal for my local area. I think this might be a factor in your case since you mentioned it being green inside (brass parts are partly copper, copper oxidizes green).

[newby200x]

You ever check for air leaks? You could have a bad carb mount or boot sucking in air, thus requiring the choke to be on at all times.

[oldskool83]

There is not Chinese replacement. Just had this issue with a guy i know with a 350x..he didnt listed to me. so later then the bike didn't run right i said rebuilt stock...he did...it ran right. When your cheap it costs to 2-3 times more then when you just fix it correctly. I think people used 250X or 300ex carbs as replacements. If not please sell the machine to someone who will put the proper parts on it.

[Rob Canadian]

If not please sell the machine to someone who will put the proper parts on it.

I don't mean to be a jerk... Not very helpful.

[Scootertrash]

I believe FlyingW has a thread somewhere on how to rebuild those carbs. I followed it to rebuild the one on my neighbor's 250ES.

Take your time and be patient. Also check for air leaks as mentioned above. After you go back thru the carb like FlyingW did. Gotta eat, I'll look for the thread later.

[dustrunner]

I bought an es with a aftermarket carb with the black plunger on the bottom. It ran but not great, I took the original carb that came in a box with spare bolts apart and cleaned it and It worked great. threw that repo in the trash . just my .02 $ good luck.

[Dirtcrasher]

If it keeps plugging up. you need a better tank/inline filter... But, ya can't leave old gas in there for too long. Just clean it right, use a good filter, you'll be fine...

[kilabeez0]

Look at my join date. Don’t tell me to sell it to someone else if I’m not going to fix it correctly. I know what I’m doing. I’m tired of messing with this carb and you can’t get a new one. I’m currently waiting on flyingvw to refurb some that he has in stock. Thanks to those who offered help. The 35 year old boots are stiff as hell and a disaster to get on all the way. I’ll check for an air leak which is definitely possible. I’ll spray some starting fluid around it

[fabiodriven]

Yup, a terribly engineered position for that carburetor for sure. Click on the link and you can see me whine about it for the first time seven years ago.

http://www.3wheelerworld.com/showthread.php/136075-Carb-problem-86-250SX

As difficult as it was to remove and clean the carburetor the first time for me, it got easier and easier every time I had to do it. It's really not that bad once you get used to it just like anything else.

You sound frustrated and I understand why you would be, but you'll get it. If you have to take the carb out every 18 months then there is a problem, and also I'd expect you'd be good at it by now. As suggested, look into an air leak or see if you're getting crud in the carb from the tank.

Bottom line is, you shouldn't have to clean your carburetor every 18 months unless you're cleaning it and then parking the bike and not running it for 18 months. You have to, have to, have to treat your gas for ethanol if non-ethanol is not available where you live.

I understand your frustration with the placement of this carb, but ultimately it's on you if the bike doesn't run right. Oh and as others stated, there is no Chinese replacement carb for these and if there were it wouldn't have helped you. Very rarely do Chinese carburetors improve a situation.

[ps2fixer]

That reminds me of a good point. Does the carb slowly get worse and worse, or does the problem suddenly surface? Also when the problem shows up, is it after sitting a while?

Fully agree, fuel stabilizer should help with the ethanol pump gas, ethanol free/recreational fuel is a lot better for our machines, but also costs quite a lot more.

Anyway, if the machine acts up after sitting, try to drain the carb with the drain screw on the bottom of it. Let atleast 1 carb float bowl's worth of fuel run out, then give it a shot. It's one of the first things I do since I generally run the pump gas. If there's junk in the carb, there's a chance it could flow out too.

[oldskool83]

If your tired of it take it to a shop, they can rebuild carbs and jet them. My buddy took his 350x there after I and a mechanic friend said just stop messing with it. We are all not good at everything. They still sell many carbed toys. I stopped jetting and rebuilds carbs because my local shop is better quicker and if it does not preforpreform right they said bring it back to get tweaked. I know pride is one thing of I did it all myseld but there is help out there. I laid asphalt patch many times....I'm not gonna pay an entire drive way. Think about the big picture. I may sound like a ahole but I build 2 bikes a year and subing things out like carb or efi settings and suspension there are better people suited to help. Sure it costs but a perfectly tuned and suspensions bike will knock you socks off. They can build my carb while I build my daughter's brain....

[fabiodriven]

If you're building two bikes a year and don't know how to jet I can only imagine what the rest of your mechanical work looks like.

[oldskool83]

I don't buy, i build then. tTe motors get sent to KB5, I started letting them tune then to the motors. its easier and faster, more dialed in then i could get. I'd get close but they get closer. Mechanical work just read my threads, wait I delete them all because of the harassment from people like you on here so I will not show what I can do or offer much help other then my smart do the point truthfully comments. I'm only here to buy a few parts anymore. I do not care about you anymore or any others. Got a part Ill give you money if not don't care.

[ps2fixer]

Not really trying to get in the middle of this, but just looks like a conflict of life styles. Some people can't afford to hire someone else to do work to the machine. I'm in that boat, but I grew up with a dad that was an auto mechanic and 95% of what broke we fixed including house plumbing, electrical etc. Heck he even built the pole barn himself, and had a small group of friends help work the cement when he got the funds ~20 years later. Sucks being low income, but we make do with what we have.

[6bt]

Chinese carbs for powersports are junk as far as I can tell.

They will however, get you a great deal on a machine that runs like crap.

I bought my 86' 250r off eBay, with original dry rotted tires for $1550.

Guy excitedly bought it, promptly installed Chinese carb, with unnumbered jets, and got it to barely run. He threw the original carb in when I picked it up. Cleaned original carb, new spark plugs and boot, and she's up and running.

Something I didn't see mentioned..if you use ethanol gas, or have machines that sit for awhile...shut the petcock off, and run machine until it stalls. My kx500 sits for 6-8 months at a time, and lights off in a few kicks, every time.

Sent from my XT1254 using Tapatalk

[ps2fixer]

Also worth mentioning that the ethanol (pump gas) fuel is corrosive and absorbs moisture from the air and separates out in the bottom of the tank. If a machine sits often, it's best to do the process above and drain the tank and use the fuel in another machine, mower etc.

Ethanol free fuel is more expensive, but doesn't suffer from those problems. Also it can last around a year without stable, 2 with stable (I've used gas older than that with no issues, just have to make sure it doesn't smell like bad gas). Basically ethanol free fuel is like the old pump gas before they put 10% (soon to be 15% from what I've heard) ethanol in it.

[jb2wheels]

Flying W's carb tutorial if you missed it:
http://www.3wheelerworld.com/showthread.php/161746-ES-SX-350X-Carb-rebuild-Tutoral

I think he has some he'd sell you outright.

He probably has some magic potion for conditioning the 30+ year old rubber so it's easier to work with.
Something like this maybe but I have not tried it:
https://advrider.com/f/threads/good-conditioner-for-old-rubber-parts.975603/