05-27-2021, 07:52 AM | #1 |
Join Date: Dec 2019
Posts: 77
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Weird carb issue
Ok so I have been experiencing a weird carb problem. I don't know if it is related to my intake setup or not as I only experience it with this particular setup. Bike is using a pe30 carb cutoff nibbi intake (cut down for clearance purposes) 35 pilot 132 main. After running WOT or high rpm anyways then say letting off the throttle to corner when you just start to reopen the throttle bike will miss for a second. If I set the needle jet to its leanest position it happens less often. (This is intermittent anyways so I have to try and cause it to happen to diagnose which is a pita). Do you guys think I need a different needle jet or is this issue maybe the pilot being a touch rich? I was thinking maybe I need a leaner jet needle. Now when I use the stock intake with the nibbi adapter I do not have this issue although my jetting is slightly different, I imagine from them being different lengths and angles, But the carb still hits the frame slightly and I have air filter to side cover issues with that setup. This is one small quirk I have not yet been successful at curing. Any thoughts or suggestions appreciated
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05-27-2021, 08:12 AM | #2 |
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Join Date: Oct 2016
Location: Houma, La.
Posts: 11,707
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A 132 main sounds a little rich. What mods have you done to the engine? Try dropping down to a smaller main jet. I ran across the same issue on my X22R when I ran the PE30.
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2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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05-27-2021, 10:59 AM | #3 |
Join Date: Oct 2020
Location: Flower Mound Texas
Posts: 904
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Go down a couple sizes on the main and see if it gets better or worse. Then you'll know which direction to go. I'd bet you're a little rich.
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2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene" |
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05-27-2021, 06:01 PM | #4 |
Join Date: Dec 2019
Posts: 77
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Jerry Ive done the ported head, cam, roller followers, exhaust, timing advance key and a cg300 cylinder. Any main lower than a 132 and it won't rev over 6k before it starts stuttering. I only notice this when the engine is loaded hard for awhile, let off then back on quickly. The part that I don't get is that I only noticed it with this intake setup. Didn't notice it with the other setup I was using but the carb was hitting the frame slightly and the filter wasn't clearing my side cover. Sorry I left out my engine details.
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05-28-2021, 08:17 AM | #5 | |
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Join Date: Oct 2016
Location: Houma, La.
Posts: 11,707
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Quote:
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2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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05-28-2021, 09:49 AM | #7 | |
Moderator
Join Date: Oct 2016
Location: Houma, La.
Posts: 11,707
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Quote:
__________________
2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel |
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05-30-2021, 09:52 PM | #8 |
Join Date: Dec 2019
Posts: 77
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I have found a #30 pilot jet. I'll try it when it comes in. I was thinking I was fat on the pilot but im about 1.25 turns out on my air screw with the 35. Is the pe30 out more normally? I actually will have to recount where it is I'm trying to remember and I haven't touched in awhile old mind slipping
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06-01-2021, 07:43 AM | #9 |
Join Date: Dec 2019
Posts: 77
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put a 32 pilot in and symptoms still there. Will try a 30 when it gets here. I just find it odd that it doesn't do it with my other intake setup, but the fitment on the bike isn't as good. Just one of those small annoying quirks. I think a leaner jet needle would help but don't know where to look for one or how to decode the one in the carb.
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06-01-2021, 09:28 AM | #10 |
Join Date: Oct 2020
Location: Flower Mound Texas
Posts: 904
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I've never had much luck with tuning out a part-full throttle issue by changing the idle (pilot) circuit. I think I'd be looking at main jet / needle.
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2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene" |
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06-03-2021, 07:45 AM | #11 |
Join Date: Dec 2019
Posts: 77
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Smaller pilot jet didn't help much just made bike harder to start mostly. I really am thinking needle or needle.jet is my issue but haven't been able to find a source online. I got another air filter yesterday, a knock off Uni filter, to replace the nibbi k&n style. Fits much better and looks better than the other. Don't know if it will help or require a total.rejet with this small change or.not. Rain kept.me.in the shed.
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06-03-2021, 08:16 AM | #12 |
Join Date: Jun 2016
Location: Arlington, VA
Posts: 258
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Sounds like a "low fuel level" in the float bowl problem. De-smoged? Tank vented? Raise your float kevel.
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4 time WERA SuperVintage Roadracing National Champion, SCTA Land Speed Record Holder, 3rd AMA Motorcycle GP of Miami |
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06-03-2021, 11:53 AM | #13 |
Join Date: Dec 2018
Location: PNW
Posts: 983
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Is that a NIBBI PE30? My China clone PE 30 has backfired a few times after Heavy throttle load. The air flow in the smooth bore around throttle closure and just open I have experienced as a different animal.
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06-04-2021, 07:39 AM | #14 |
Join Date: Dec 2019
Posts: 77
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This kinda sounds like what I sometimes experience. Its less prevalent with the needle in the #1 position so I really think I need a slightly leaner needle but can't find one
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06-04-2021, 07:41 AM | #15 |
Join Date: Dec 2019
Posts: 77
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Already adjusted float height. Thought the same thing. I did however wonder about fuel flow as my line is a little long and has a kind of S shaped bend in it. Never tried shortening it though.
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