rjm3
Scoot Junior
Posts: 15 
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Post by rjm3 on May 23, 2018 15:57:19 GMT -5
The carb on my vip has a gold cap on top and my spare carb has a black cap on top they are close in appearance just wondering if it will fit on my back up scooter and work
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Post by tocoo on May 23, 2018 18:37:42 GMT -5
measure the OD of the input and output. for ex, the output  you can also measure the diameter of the plunger and also see if the enriching circuit is removable or cast into the body of the carburetor |
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Post by GrumpyUnk on May 24, 2018 10:32:34 GMT -5
It seems they are all very close. But tocoo is correct that to fit, both ends of the carb, inlet and outlet, must fit into the rubber bushings or it will not work.
The 'black cap' units are more common in aftermarket, while the 'gold top' are more common as OEM. I don't know if there's a lot of difference. In most cases, selecting a good combo of pilot and main jets is more important than the brand of carburetor, but brand name carburetors, such as Keihin, seem to provide better operation and economy. 90GTvert has a video about an upgraded carb, no wait, it's Jenny's Garage(Jennies) who got a Keihin and a clone, and did a comparison. The clone was close, the Keihin was better, and BOTH beat the factory carb in power & economy. Maybe I am confused.
tom
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Post by cagiva4ever on May 24, 2018 14:32:20 GMT -5
on the Subject: What ever china CVK carb on what ever China scooter, your ever handle and INSPECT, ABSOLUTELY always dismantle and check the Mixture scew and its tiny O-ring/metal washer and Spring.
on past week ive gone through about 5 different 139QMB CVK's out of interest and continued studyes...Complite spec check and measuring Needles Float weights Float height etc everything, and every chinese details on them 5 CVK's that were different Due CutBacks on saving costs at Factory...
at 1 i had overlong Spring on the Mixture screw that i think "bottomed out" before Mixture Screw was even closed.
normal Spring should have 4 windings + ends, so in total 6. them Overlenght faulty springs have in total about 9 rounds.
also them Overleght springs tend to wornout destroy the tiny delicate Threads from the Mix screw. its uber Springy,way too much Tension stress on the Thread when Winding it in or Out. Also needs Pushing in before Screw even catches 1st Thread and starts to go IN via Thread.
it also tends to Crush in mangle the tiny washer in front of the tiny O-ring.
blody chinese wonky standards...
Also them 45mm long Needles tend to either BottomOut or hit crooked into the Nozzle/Atomizer.. and Bend from tip....on past week ive handled about 5 different spec Needles....
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Post by katt on May 25, 2018 7:12:55 GMT -5
My carb saying made in japan is it aftermarket?
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Post by GrumpyUnk on May 25, 2018 10:27:41 GMT -5
Newarly all OEM carburetors are hecho in China. Some aftermarket are made in Taiwan, some in Japan, and some in China. Given Far East patent and trademark protection levels, I would not bet the farm, or a donut, that the "Made in Japan" marking means what it says in English. The words may be considered just part of the design, with no implication as far as country of origin. OTOH, I think Apple or IBM would be a bit perturbed if Hecho in China items started appearing with their corporate name & trademarks... Made in Japan is more generic, and less likely to be opposed by an individual manufacturer, so may slide by more readily.
In short, verbiage aside, it is too hard to say with any confidence who made what, and where, unless it has a non-brand name. Some carbs marked Kun-Fu, for example, are more likely to be marked with their true country of origin than one with a 'brand' name such as Keihin. It is too easy to copy a Keihin, and plop words onto a plastic cover. I honestly would trust a lesser 'brand' to be more accurate in source and brand than a more well-known brand.
In short, it is more likely aftermarket than OEM, IMO.
tom
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Post by cagiva4ever on May 25, 2018 16:16:26 GMT -5
"Kun-Fu" and "Standard of zc" might be the 2 most common ones fround on "10 wheel 139qmb shortcase.
i have also 1 Walbro, "Walbro. Designed in Japan" titled on the lid. but still yet again china made. walbro do have a factory in India for manufac and r&d, making EFi's and small engine chainsaw carbs etc.
btw, has any1 experimented with various diff 139qmb CVK's that which1 has the most easy removable Diaphram, meaning taking the diaphram alone of from the Throttle slide... some 139qmb CVK's have more or less tightly compressed "sealed" mushroomed top of Throttle slide....pinching diaphram tighly between discs...
i dont have brokens ones to test... and im always looking for suitable Diahphrams alone for my early 2000era 139qmb CVK "Flat slide" carbs...
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