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Post by opie on Jan 26, 2017 15:11:42 GMT -5
I bought an adjustable carb and it's slower on top end than the original.im gonna reject.the distributor says that there'sa 78 in it and I can go dwn to 75.would yu advise going straight to the 75 thousandths or wrk dwn starting at 77 76 to 75
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Post by onewheeldrive on Jan 26, 2017 20:25:56 GMT -5
I'd look at the jet # that is in the new carb regardless of what any manufacturer or parts dealer says it's supposed to have.
Compare the numbers on the old and new jets. Use the old jet if you still have it.
Anything in that range should be fine if it's still stock, unless it's really a 63cc as some are, but still should run fine.
Is the carb the same size in mm as the old carb?
Any mods done to the scooter?
Trial and error--- play with the jets is the only way, imo.
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Post by opie on Jan 26, 2017 22:38:46 GMT -5
The carb is supposed to be the same size as the original.18 millimeter I was told.only other thing I've done is put a better air filter system on it.an air filter pod instead of the big box.i adjusted the needle under the top cap up from the center increment all way to top one after I first went dwn it and it improved top end performance but caused an off idle hesitation.so I've decided to go bk to center on needle and change main jet.
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Post by opie on Jan 26, 2017 22:41:15 GMT -5
Thank you for your helping me onewheeldrive!!
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Post by onewheeldrive on Jan 26, 2017 23:03:48 GMT -5
Well a lot depends on when you put the pod filter on (before or after the new carb?)
When you allowed more air into the carb (pod filter), did you use a bigger main jet? More air usually means bigger jet.
That's why it's important to know what jets you have (or had) in both carbs.
You might need to upjet, not downjet.
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Post by opie on Jan 29, 2017 16:31:52 GMT -5
I drilled out screws on old carb to see what jet was there it was a 75 so I put it in place of the 78 that had come in the new one.doing that helped a lot although it's odd that the new one wouldn't run lean enough the 78 considering I'm getting much more air too because I put the adj.carb and air pod on as a pair.i still believe I can get a better top end performance by going abit more lean or if not that by getting another 75 and step drilling up to 76 and even 77.im not sure just how sensitive it is by just changing setup by only a thousandth at a time.i may be wrong but I'm thinking I can still go just a little more lean on main to increase rpm on topend.i feel pretty good on being right that I needed to lean new carb up instead of the other way.i wanted to ask if the slow spd needle is an air needle instead of a fuel type.it seems that I richened mix at idle by turning clockwise cause before I did so the eng tended to burp and quit if I didn't get past idle deeper on into the intermediate or main jet end.Are these carbs considered three stage?idle, intermediate,and of course wide open stage.
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