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Post by smicsmit on Jun 6, 2022 13:54:22 GMT -5
I recently bought a 2017 Bintelli sprint. The airbox was busted, so I bought a new 19mm carb and a pod airfilter. I messed around with the main jet, and decided to go with an 88. It runs well, seems to to out around 35mph, all good. The only problem is when I stop. If I try to take off with just a tiny bit of throttle, it loses power and threatens to shut off. If I give a lot of throttle to take off, there doesn't seem to be an issue.
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claydoh
Scoot Enthusiast
Posts: 172
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Post by claydoh on Jun 6, 2022 14:13:59 GMT -5
Did you adjust the mixture screw to tune the carb after swapping the jet?
You probably need to adjust the carb needle height. The transition from the idle circuit to the main may be too big a change. It might not be cured completely, but you should be able to at least reduce the severity by a good bit, if you don't eliminate it. I'd suggest starting out by lowering the needle (by raising the clip to a higher slots) and testing.
You might try swapping different idle jets if it is still bad after testing different needle heights. Then you probably will still need to re-adjust that needle again.
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Post by smicsmit on Jun 6, 2022 16:46:38 GMT -5
Did you adjust the mixture screw to tune the carb after swapping the jet? You probably need to adjust the carb needle height. The transition from the idle circuit to the main may be too big a change. It might not be cured completely, but you should be able to at least reduce the severity by a good bit, if you don't eliminate it. I'd suggest starting out by lowering the needle (by raising the clip to a higher slots) and testing. You might try swapping different idle jets if it is still bad after testing different needle heights. Then you probably will still need to re-adjust that needle again. Thanks! I will adjust the needle when I get a chance. I did adjust the mixture screw; I guess an 88 jet is still rich because it idles best when the screw is all the way in .. Or is that related only to the pilot jet? |
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claydoh
Scoot Enthusiast
Posts: 172
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Post by claydoh on Jun 6, 2022 17:52:18 GMT -5
Thanks! I will adjust the needle when I get a chance. I did adjust the mixture screw; I guess an 88 jet is still rich because it idles best when the screw is all the way in .. Or is that related only to the pilot jet? It seems to indicate a rich idle, so you may need to try a smaller pilot jet. if you have the original carb, you might just swap that in for the one in your new carb to see if it helps.
Worth reading the whole page, it is really helpful.
It will take some trial and error to dial it in better.
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Post by smicsmit on Jun 8, 2022 21:10:32 GMT -5
Thanks! I will adjust the needle when I get a chance. I did adjust the mixture screw; I guess an 88 jet is still rich because it idles best when the screw is all the way in .. Or is that related only to the pilot jet? It seems to indicate a rich idle, so you may need to try a smaller pilot jet. if you have the original carb, you might just swap that in for the one in your new carb to see if it helps.
Worth reading the whole page, it is really helpful.
It will take some trial and error to dial it in better.
I took the pilot jet out, it's a 33. Pulled the pilot jet off the old carburetor, its a 28. Tried using the 28, but it would barely start, and when it did, it didn't sound happy and wouldn't stay running. Replaced the 33, pulled the needle (the clip was at the lowest notch) and put the clip all the way at the top groove... Much worse! Put the clip in the middle groove and it's better, though it still sounds a little rough when I give it throttle after slowing down from WOT. I'll try a notch up/down after work tomorrow, but your advice definitely helped! At least it doesn't try to cut off now when I go from WOT to 1/4 throttle. Thank you for your help, really! |
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claydoh
Scoot Enthusiast
Posts: 172
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Post by claydoh on Jun 9, 2022 6:28:48 GMT -5
I took the pilot jet out, it's a 33. Pulled the pilot jet off the old carburetor, its a 28. Tried using the 28, but it would barely start, and when it did, it didn't sound happy and wouldn't stay running. Replaced the 33, pulled the needle (the clip was at the lowest notch) and put the clip all the way at the top groove... Much worse! Put the clip in the middle groove and it's better, though it still sounds a little rough when I give it throttle after slowing down from WOT. I'll try a notch up/down after work tomorrow, but your advice definitely helped! At least it doesn't try to cut off now when I go from WOT to 1/4 throttle. Thank you for your help, really!
Did you re-adjust the mixture? it shouldn't be screwed all the way in. You may still down the road want to try different idle jets, just closer to the 33  28 is quite a big jump |
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28 is quite a big jump