Those of you running a 30mm carb, what jets are you using?
Right now i've gone down to a 110 / 35 and it still seems too rich.
Not sure if i need to go lower or if something else if causing issues. Like maybe i'm misfiring or timing is slightly off or something.
I've seen ruckus folks with gy6 swaps that are running 120/40 which seems right to me, but so far i've had no luck yet with my upgrades.
my setup
61mm BB (170cc)
PP large intake head
30mm CVK with pod filter
Prima pipe
thanks,
-duo
Those with 30mm Carbs - What Jets?
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SYMbionic Duo
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Those with 30mm Carbs - What Jets?
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babblefish
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I have a 30mm CVK carb on my scoot, but haven't run it yet because I'm still finishing up the engine rebuild and an overall scoot refurbish. Here are the specs on my engine:
61mm bore
62mm stroke
Total displacement = 180cc
Ruima large port head that has been "massaged" a bit more
30mm NCY intake manifold
Exhaust has not arrived yet, but it is a no name carbon fiber can type made in Taiwan.
Cam = A12
11gm variator sliders and 1500 rpm torque spring and clutch springs. I'm expecting the engine's power to be moved up in the rpm range so wanted the transmission to allow the engine to rev higher on take-off.
I was going to run a Unifilter pod filter, but decided against it and use the stock airbox instead, partly because the larger carb would not allow mounting the pod filter in the engine compartment thereby exposing it to outside elements. I ride year round so weather protection is important. I found a high flow, reusable air filter that is a direct replacement for the stock filter in the air box so it was kind of a no brainer.
Also, while a lot a people have successfully used pod filters with their CVK carbs, many have had tuning problems that took a lot of work to solve. Most of what I've heard is from motorcycle guys, not scooter people, but the physics should be the same. The main issues I've heard about is engine surging and not being able to run at full throttle. The most common cause is a sporadic lean condition and uneven air flow which greatly affects the operation of a CVK carb's vacuum operated throttle slide.
Do an internet search using the term "how do pod filters affect cvk carburetors" and you'll come up with a lot of interesting reading material that might help with your tuning.
If you're interested in what I've done to my engine and other interesting things to talk about at parties (...or not, lol), go here: topic16629.html
Final thought - I have a nagging thought in the back of my mind that a 30mm carb is going to be too big for a 180cc engine that is going to be used on the street, so my backup plan is to go with a 26mm carb if I can't get the engine to run well.
Best of luck.
61mm bore
62mm stroke
Total displacement = 180cc
Ruima large port head that has been "massaged" a bit more
30mm NCY intake manifold
Exhaust has not arrived yet, but it is a no name carbon fiber can type made in Taiwan.
Cam = A12
11gm variator sliders and 1500 rpm torque spring and clutch springs. I'm expecting the engine's power to be moved up in the rpm range so wanted the transmission to allow the engine to rev higher on take-off.
I was going to run a Unifilter pod filter, but decided against it and use the stock airbox instead, partly because the larger carb would not allow mounting the pod filter in the engine compartment thereby exposing it to outside elements. I ride year round so weather protection is important. I found a high flow, reusable air filter that is a direct replacement for the stock filter in the air box so it was kind of a no brainer.
Also, while a lot a people have successfully used pod filters with their CVK carbs, many have had tuning problems that took a lot of work to solve. Most of what I've heard is from motorcycle guys, not scooter people, but the physics should be the same. The main issues I've heard about is engine surging and not being able to run at full throttle. The most common cause is a sporadic lean condition and uneven air flow which greatly affects the operation of a CVK carb's vacuum operated throttle slide.
Do an internet search using the term "how do pod filters affect cvk carburetors" and you'll come up with a lot of interesting reading material that might help with your tuning.
If you're interested in what I've done to my engine and other interesting things to talk about at parties (...or not, lol), go here: topic16629.html
Final thought - I have a nagging thought in the back of my mind that a 30mm carb is going to be too big for a 180cc engine that is going to be used on the street, so my backup plan is to go with a 26mm carb if I can't get the engine to run well.
Best of luck.
Some people can break a crowbar in a sandbox.
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avescoots1134
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