Spit and sputter

Wild Piggy · 08-09-2018, 05:07 PM

We just did a big bore upgrade to 80cc on a Mad Dog scooter. We changed carbs 5 times, new CDI, coil, stator, spark plug twice, even changed the head again. Starts and runs fine, until you take off, then it starts to spit and sputter. We pulled the engine out and replaced it with a brand new 49cc out of the box. Ran great, NO spit and sputtering. Any suggestion would be greatly appreciated.

**JerryHawk250** · 08-09-2018, 05:12 PM

We will need a little more information. What size carb and what size jets? are you using the same carb and jets from the 49cc on the 80cc? BTW welcome to the forum.

Gh426 · 08-09-2018, 06:46 PM

are your cases sealed? vacuum leak??

08-09-2018, 05:07 PM	#1
Wild Piggy Join Date: Aug 2018 Location: Vermontville, Mi Posts: 1	Spit and sputter We just did a big bore upgrade to 80cc on a Mad Dog scooter. We changed carbs 5 times, new CDI, coil, stator, spark plug twice, even changed the head again. Starts and runs fine, until you take off, then it starts to spit and sputter. We pulled the engine out and replaced it with a brand new 49cc out of the box. Ran great, NO spit and sputtering. Any suggestion would be greatly appreciated.
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08-09-2018, 05:12 PM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,555	We will need a little more information. What size carb and what size jets? are you using the same carb and jets from the 49cc on the 80cc? BTW welcome to the forum. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 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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08-09-2018, 06:46 PM	#3
Gh426 Join Date: Feb 2018 Location: LA Posts: 74	are your cases sealed? vacuum leak??
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