shortman1166
Scoot Member
Posts: 52 
Location: Lafayette, Indiana
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Post by shortman1166 on Jul 22, 2018 18:47:55 GMT -5
Scooter runs great, idles fine, WOT fine, but when I transition from 1/4 ish to more throttle quickly it hesitates for a second or two then revs up. I have tried adjusting the needle and it did not stop it. What else could cause this? Also if I roll on the throttle slowly it does not hesitate, only when I try to adjust the throttle fairly quickly. Any thoughts?
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Post by Happypancake! on Jul 22, 2018 19:09:11 GMT -5
Helps if you post type of scoot
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shortman1166
Scoot Member
Posts: 52
Location: Lafayette, Indiana
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Post by shortman1166 on Jul 22, 2018 19:34:44 GMT -5
Sorry, it says at the bottom of the post as well... but its gy6 49cc with a 72cc bbk. Tao Tao Cy50A
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Post by Happypancake! on Jul 22, 2018 19:38:35 GMT -5
Sorry. Working from Tapatalk
Jet sizes?
RPM ranges?
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shortman1166
Scoot Member
Posts: 52
Location: Lafayette, Indiana
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Post by shortman1166 on Jul 22, 2018 20:55:45 GMT -5
85 main 30 pilot if I go bigger on the main it cuts out at wot and the pilot is 2 3/4 turns out on the screw with highest rpm at that point. the throttle hesitates at about 6k on the tach but its at about 1/8-1/4 throttle, I tried a larger pilot and adjusting the screw a bit each way just to see if it would change anything and it did not. valves are at .004" each blue cdi, iridium plug, a9 cam
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Post by scooterpimp on Jul 22, 2018 20:59:19 GMT -5
Did ya try ajusting needle height?
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Post by Happypancake! on Jul 22, 2018 21:36:54 GMT -5
Main jet does not kick in until 3/4 open on throttle. Either clip position on slow jet. 30sj seems too small is I run 38 for my 48 and 58cc 4ts. If lowering the clip (raising the needle) didn’t work, I’d suggest upping the sj. Also, I’d your specific carb has a vacuum hose on the carb diaphragm, make sure it’s tight. Cheers
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Post by tocoo on Jul 23, 2018 11:15:37 GMT -5
Scooter runs great, idles fine, WOT fine, but when I transition from 1/4 ish to more throttle quickly it hesitates for a second or two then revs up. I have tried adjusting the needle and it did not stop it. What else could cause this? Also if I roll on the throttle slowly it does not hesitate, only when I try to adjust the throttle fairly quickly. Any thoughts? I have the same situation with my generic aftermaket carburetor and it is due to the needle position, after you have set the idle jet within the 1,5 turn--3 turn of the mixture screw. Perhaps your needle is already too fat or too thin, in order to see a change in height. could this be possible ? With the original carburetor, I have no problem with the transition, which is why I use this one. |
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Post by GrumpyUnk on Jul 23, 2018 11:43:00 GMT -5
Did you check that the accelerator pump is being activated when the throttle is opened? It should do a short 'squirt' when the plunger is depressed by the flat lever on the throttle linkage. I understand not all carbs have one, but...
A hesitation on acceleration may be caused because the throttle opens quickly, the AIR moves quickly being a less dense gas, but the FUEL moves slowly, trying to catch up, due to its density. It just won't flow as quickly as air inside, and gets left in the dust when the throttle is opened quickly.
If the original mix is marginal, say leanish, quick throttle will expose that. Possibly.
tom
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