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Old August 10th, 2023, 06:31 PM   #1
DallasDude
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Lightbulb Anyone tried the eBay/Amazon Chinese carb?

I have searched a lot online and only found a few mixed reviews on Amazon with one pregen owner saying it did the trick. The price is 100bucks. Thatís 900 bucks cheaper than an oem carb on partzilla. I recently cleaned my carb and put it back together and it has the dreaded overflow gas leak only while running. From reading here it sounds like a stuck float. Rather than messing with it I decided to have a professional ultra sonic clean and rebuild it. Found a guy does carbs only on eBay and replaces with oem Japanese parts with 100% positive feedback for 300 bucks so off they go to him. In the meantime I thought why not give these brand new Chinese oem carbs a try for 100 bucks. If anything I might keep them as a backup when doing long travels to swap on should any issue happen since most issues in my experience with these bikes running seem to be the carb. ( this is my second pregen)

My other issues Iím dealing with,
Bought it used not running derusted the gas tank vinegar then electrolysis clean now and runs smooth except the leaking carbs thatís being addressed.

When I got it the starter selenoid must have stuck because it kept trying to start after releasing start button. I replaced it with a very new looking used one on eBay along with a newer used right control off eBay. Now that itís installed nothing. No click sound nothing. Iím guessing I got a bunk selenoid so just ordered a brand new one. Hopefully that solves it. If not Iíll try a new control and I already made sure clutch cable was plugged in. I mean the bike would try to start when I got it. It must be the selenoid unless the wire harness went bad recently. The way I was able to start it was just putting needle nose across the two selenoid connections to test the carb.

I also went with the dynojet needles and decided to wisely not drill out my carbs. Also I feel the main jets they provide arenít a good idea seeing as already the bike runs a little lean from the factory due to epa. They provide 4 jet sizes and recommend smaller main jets with their needles if using factory airbox. I decided to skip that idea because itís already lean and Iím not sure their needles will make it run much richer however I get that their needles give good and better mid range and smoother response so they do provide bigger main jets but recommend them only if running pod filters which Iím not planning on. Knowing all this I decided to see how it goes with the stock 105 main jet size and dynojet needles with airbox and factory exhaust. Iím also at notch 3 on needles. If it runs just a tad richer than stock only from the needles then thatís perfect. Rather be on the richer side with a smoother powerband and idle.

Hopefully this bike has a long life. Only has 10k miles. Another issue is spark plug not as tight as I want. Itís tight but canít get tighter. Maybe previous owner stripped it. I noticed 2 drop of oil from the top valve cover that dropped down to spark plug hole. Maybe previously overfilled with oil. I could try to get a rag in the hole to clean the threads of oil then do a 2000f ceramic loctight on it just to be safe but time will tell if itís good enough as is.

Hopefully Iíll be back here with some post build pictures and info thatís positive.
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Old August 10th, 2023, 07:17 PM   #2
Triple Jim
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Ducatiman, on this board, restores carbs to as-new condition for a very fair price. I had him do mine. I'm pretty sure an aftermarket carb set is going to be a huge mess to try to get running.

What do you mean you can't get a spark plug tighter? Do you mean it turns but never gets tighter? If so you're in for a thread-repair job, because the problem isn't going to go away.
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Old August 10th, 2023, 07:57 PM   #3
DallasDude
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Quote:
Originally Posted by Triple Jim View Post
Ducatiman, on this board, restores carbs to as-new condition for a very fair price. I had him do mine. I'm pretty sure an aftermarket carb set is going to be a huge mess to try to get running.

What do you mean you can't get a spark plug tighter? Do you mean it turns but never gets tighter? If so you're in for a thread-repair job, because the problem isn't going to go away.
Good to know Iíll keep that in mind next time but already sent mine off. The aftermarket carbs being sold on eBay and Amazon are suppose to be to oem spec. One Amazon review said they worked right out of the box plug and play.

About the spark plug yeah it will turn and turn but the amount of force to make it turn and turn is still a good amount. Doesnít turn so easily I mean but yeah never gets tight. Not like the left one. It has me curious if itís snug enough. I have a feeling high heat ceramic loctite would keep any vibration loosening in the future as tight as itís in now. Should probably go that route. But definitely want to avoid a rethread job.
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Old September 8th, 2023, 11:08 AM   #4
DallasDude
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Just wanted to give an update on the Chinese carbs as there is not a lot of info out there despite amazingly one ebayer sold 479 of them for the ninja 250 another ebayer sold 256 and another 243 and then thereís Amazon so basically 2000 plus buys of these ninja 250 specific Chinese carbs you would think just one of those 2000 buyers would be a member of this forum, I guess not. Well I tried to install them after my original rebuilt carbs were bogging between 1-3k rpmís so I thought letís just see how these chinese carbs run. No idea how they are jetted. Everything fit except for one thing. The throttle cable holders where you got two nuts top and bottom that part does not slide in and fit on the Chinese carbs. Itís a bit too tight. Maybe you could pry them out just a little to make them work. At that point I gave up and reinstalled my freshly cleaned rebuild oem carbs with the 1-3k rpm bogging issue that Iíll need to work with and figure out later. So there it is. Chinese carbs are exact fit and copy except for the throttle cable holders to anyone wanting to know. No idea how the 2000 plus buyers got them working, guess they pryed out the cable holders.
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Old November 11th, 2023, 07:51 PM   #5
How2
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Ebay carbs / 11/23 purchase review

Got one of these from a vendor with a 99% customer score.
https://www.ebay.com/itm/256268546904

Here is the current lowdown compared to a 2003 stock carb that has been sitting for decades and just wont cooperate. Bike has exactly 2015 miles sitting in a garage.

Comparing the stock and Ebay

1) ebay slide needle clearly thinner than stock
2) Slide does not sit flush with the carb body- visually obvious
3) Pilot jet is a button type that fits high like a main jet and has no size stamp. The stock pilot is screwed inside the pilot tower. A completely different design
4) the outlet port that goes to the high mount diaphragm (for fuel flow) is placed closer to the airbox
5) 3 main jets come with the carb: 122,123,125. The stock main jet is 105.
6) Drain/ overflow is done with a tube extending in the upper part of the carb. Stock does not have this.
7) the choke slide that mounts the cable is a bit longer and the cable is more taut. How much I dont know.

As a test I put the stock jets in the Ebay carbs.
Accel was boggy through the entire range, but I did lose the problem with the idle loitering on decel at 2 k RPM. The bke ran significantly hotter and the fan started as opposed to the stock set up. Very strange , I expected it to run rich.

Currently, this carb is not the same and in no way, plug and play

Conclusion.

The stock carbs have been sonic tanked 4x, on and off I forget how many times.

Once I get it running moderately, this POS is going bye, bye. Never in 50 years had this much problem with a carb.
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Old November 12th, 2023, 07:20 AM   #6
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a request.....for discussion purposes....could one of you post 2 photos of the subject Far East carbset laid out as such?

Thank you in advance.
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File Type: jpg 108-5.jpg (90.1 KB, 0 views)
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Old November 18th, 2023, 08:14 PM   #7
How2
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I found the issue with the OEM carbs

The OEM pilot jet is wrong , went up +1 size
The OEM slide needle is too lean- went with an after market vendor

The fuel/ air screw is too lean. Went 3 turns out for California

Now the bike runs like it is suppose to .

I have a near mint 250 with 2100 miles for sale in the SF bay area.

If any one is interested PM me, lets talk
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Old November 19th, 2023, 05:43 AM   #8
Triple Jim
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Quote:
Originally Posted by How2 View Post
I found the issue with the OEM carbs

The OEM pilot jet is wrong , went up +1 size
The OEM slide needle is too lean- went with an after market vendor

The fuel/ air screw is too lean. Went 3 turns out for California

Now the bike runs like it is suppose to .

I have a near mint 250 with 2100 miles for sale in the SF bay area.

If any one is interested PM me, lets talk
I found that when my '05 stock carbs were truly clean and adjusted correctly, with all rubber seals and hoses in good condition, they run perfectly. Previously they seemed lean in places like idle and cruise throttle and I had shimmed the needles. It seemed I was making adjustments to compensate for carbs that were not truly clean.
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Old November 19th, 2023, 06:53 AM   #9
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the bike ran perfect right out of the showroom with stock supplied jetting, no?

So why (with just 2100 miles) would you need to mod both pilot and midrange circuits with oversized jetting to supply (the old jet kit mentality) more fuel fuel fuel?
Thus totally masking the situation.

Please post your current MPG, and good luck with your sale.
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Old November 20th, 2023, 08:44 PM   #10
How2
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Why oh why

Cause the jetting from the factory is for different fuel compositions and EPA compliance : not very functional

In the initial phase of tanking the carbs the bike ran asthmatically, along with that common decel hang-up. As wrenching these things is not my 1st rodeo, it definitely felt lean and gutless.

A teenager on a skate board had more umph, than this thing!

My assessment also was the chain was too tight and needed lubing.

A quirk of this bike is there is a small fuel filter inside the inlet port/ elbow of the carb. Since my scooter was sitting for decades, I believe that tiny filter was plugged. So out it came.

I did leave out the part that the valves needed adjustment - yep too tight

With the various things done, the bike runs very respectable. Also did some cosmentic upgrades to improve it. Its for sale if some one is interested in N. Calif.
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Old November 21st, 2023, 11:40 AM   #11
ducatiman
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Quote:
Originally Posted by Triple Jim View Post
I found that when my '05 stock carbs were truly clean and adjusted correctly, with all rubber seals and hoses in good condition, they run perfectly. Previously they seemed lean in places like idle and cruise throttle and I had shimmed the needles. It seemed I was making adjustments to compensate for carbs that were not truly clean.
@How2....care to explain the above?
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Last futzed with by ducatiman; November 21st, 2023 at 01:53 PM.
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Old November 22nd, 2023, 08:54 PM   #12
How2
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Perspective - Lean

As I am in California, the stock jetting is too lean on the needle and pilot.
Adding a .3 - .5 mm shim will pull the needle up, which will richen the fuel mixure. That might be enough for a particular rider.

There is a subjective angle on who considers "perfect" running is.

Adding more shims pulls the stock need out of the pilot jet circuit and moves into the tapered part of the needle. The taper in the needle affects drawing significantly more fuel. Maybe a bit too much for the pilot circuit.

in 50 years of building bikes, there are specific characteristics I look for.
- If adding the shim is ok for that rider- well who am I to correct?

If you are curious to know the fine points or get the maximum out of the carb , Mark at Factory Pro (Calif)has been doing this a bit longer than I have and knows this bike up and down, in and out.

At this point I have mine just where it should be with each designed fuel circuit doing what it should do, without hindering a different fuel circuit.

Odd thing about my 2k mile bike, is that the valve adjustment was out of spec and needed adjustment. I can feel the difference when valves are adjusted and the chain is properly lubed with the correct tension.

Can't speak for anyone else or what they are satisfied with. Just my .02$

Peace out
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