Author Topic: Carb runs well with air screw almost all the way seated  (Read 1069 times)

bigwillee

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Carb runs well with air screw almost all the way seated
« on: September 18, 2015, 07:48:56 PM »
I just bought a 2007 Kymco people 50 2T with about 11,500 miles. I was told that it had a engine rebuild at 5000 miles (not km). I'm not sure if it was a big bore kit or still 49cc, but the scooter gets up to about 45 on flat ground and 50 downhill. The variator is derestricted, but the exhaust is still restricted. So my question is when tuning the carb, it really only works well when the air screw is turned in all the way then backed out about 1/4 - 1/2, any ideas on why? Air leak? Big bore kit with different jets (haven't checked yet)? Or is this within spec? Any help would be greatly appreciated.

BettinANDlosing

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Re: Carb runs well with air screw almost all the way seated
« Reply #1 on: September 19, 2015, 02:54:25 AM »
Hey there welcome to the forum, the people 50 carb has a fuel screw, meaning that the tighter it is the less fuel it's getting. They ideally run at about 3/4 out. The dash is also in km not miles. Not sure why it would need to be turned in all the way I would start by taking the carb apart and cleaning and inspecting everything.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

chaz35

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Re: Carb runs well with air screw almost all the way seated
« Reply #2 on: September 28, 2015, 02:52:50 AM »
I don't know why, but I normally have to turn air screw out only 1/4 to 1/2 turn to get it to run right.  Sometimes, it likes turned in all the way.  I have 2 Super 9's and 1 People 50 2T and they all like the air screw turned in more than recommended.  If it's running well, I wouldn't worry about it very much.  Check your plug to be sure not running too lean.  Actually, the less you turn it out, the richer the mixture, as I understand it, so you are probably safe.  Cheers
1st and 2nd usually have an unfair advantage.  3rd is usually the best, can learn the most from.  paraphrased from Don Quixote, over 400 years ago, still true today

bigwillee

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Re: Carb runs well with air screw almost all the way seated
« Reply #3 on: September 29, 2015, 04:35:02 AM »
Thanks. That puts my mind at ease! I did a couple plug chops and it looked okay, just didn't know if something was clogging my intake or something. But if that is what works for others, I'll just stick with it. Thanks again!

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