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Post by colorado on Dec 14, 2011 11:48:49 GMT -5
Hi: New to the board. I just about read all the threads about carburation, jets, etc. without really getting the answer I am looking for.
I live outside the USA and only use my motifino 150cc for about two weeks every 5 months and my stock carburetor is done for for sitting too long. I will start draining the fuel bowl but it is hard to get at. I am planning to shut off the fuel supply and let the engine run until it runs out of fuel as in outboard motors.
My stock 24mm carb. is shot for sitting too long without running so my question is: What are the pros and of replacing the 24mm with a new 26mm carb with its corresponding 26mm intake manifold.
I am also changing to a new h.p. cdi with h.p. coil. (already have an ngk plug)
I am getting a direct air filter to attach to the new carb. Another question: Should I just keep the stock filter/canister or would the 26mm run better with a direct air filter without messing with the jets, etc.
Thanks
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Post by rattlerviper on Dec 14, 2011 11:54:52 GMT -5
It's easy to drain the fuel bowl. There is a line that runs from the carb to the bottom of the cvt that has a screw in it. Open the screw and presto you have drained the bowl.
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Post by Scooter Elements on Dec 14, 2011 12:13:55 GMT -5
most that upgrade in a 150cc go from the 24mm carb to a 30mm and just lower the jet.
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Post by macktheknife on Dec 14, 2011 13:49:35 GMT -5
Waste of time IMO. Head intake is 24mm so why try to feed gas in from a 26 or even a 30mm carb?
Even it was stated put 30mm on and reduce the jet, why just not increase the jet on the designed 24mm carb all the same plus the intake manifold and fuel travel will do better on the same size as it was designed for. Bigger carb needs to have and manifold the same and head intake which requires porting and polishing.
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Post by 50dude on Dec 18, 2011 19:02:33 GMT -5
I believe it's something to do with air flow versus air volume. A bigger carb will let in a higher volume of air, but a smaller carb will flow it faster.
A small carb is good for low end, a big carb will sacrifice low and power for high up power.
26mm is about right for a 150, a 28mm would be the limit.
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Post by macktheknife on Dec 18, 2011 20:31:53 GMT -5
I believe it's something to do with air flow versus air volume. A bigger carb will let in a higher volume of air, but a smaller carb will flow it faster. A small carb is good for low end, a big carb will sacrifice low and power for high up power. 26mm is about right for a 150, a 28mm would be the limit. Doesn't matter about the big carb, if the head intake is smaller then all the fuel and air that comes in will be regulated by it's ID. It's like putting a 1" outlet on a 2" pipe all the flow you get is what the 1" pipe lets out. People get all wrapped up in the idea of more fuel, if the air isn't there to support more fuel then you reduce the jet to match the air. In fact by putting a larder ID carb on and then having the ID of the head intake smaller you actually create a lip that interrupts air and fuel flow dynamics. But you can just as easily upjet the correct size ID carb matched to the head intake and acheive as good as or better results. IMO it just doesn't make sense to put on a larger carb and then downjet it when the same results can be done with the correct size carb?  |
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Post by Scooter Elements on Dec 19, 2011 11:24:20 GMT -5
the 30mm Carb i was talking about was this one which is a guillotine carb no vacuum its a straight shot when you turn the throttle the gas goes unlike the Standard 24mm Vacuum carb that in order for that gas to go when you turn the throttle you need vacuum to raise the needle for more gas. and yes you do need a bigger intake manifold to install a bigger carb but they are worth it. when i changed my stock carb for one of these i got a nice boost in power and responce  |
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Post by inkyben on Dec 19, 2011 12:13:09 GMT -5
That's one thing I never changed on my scoot. Still usin a 24mm stock carb w/ a 125 jet.
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Post by Scooter Elements on Dec 19, 2011 12:46:05 GMT -5
That's one thing I never changed on my scoot. Still usin a 24mm stock carb w/ a 125 jet. before i switched my scooter had the stock carb with the same exact jet and when i switched over to the one i posted and i changed the jet to a 125 also and the responce when i turn that throttle was way better than the stock carb and higher MPH. I sell out of the OKO carb here all the time. right now i am sold out lol waiting on more to come in on Saturday. |
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