Slowlane wrote on 12/11/20 at 08:20:12:2009 S40 Calif model 939miles Florida Panhandle.
I would appreciate some advice on which carburetor kit to order. I live practically sea level.
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Keep everything stock. Don't buy an aftermarket kit! It should run reasonably well to perfectly fine with stock jetting. At this point you have what sounds like a fuel delivery issue, NOT a tuning issue.
It sounds like it's starving for fuel. While some find that these bikes run a little lean, a properly functioning bike will not suffer from fuel starvation.
I think you are probably on the right track thinking you may still have some restrictions in the carb. But before you go too far, you should make sure your slide is functioning properly.
The slide is actuated by a vacuum created when the throttle plate is opened. If the slide doesn't respond to the vacuum, you won't get enough fuel to go with the increased air being pulled into the engine. This leads to a lean condition.
There are 3 main factors in play here:
1) There are air jets in the top of the carb. One is a main jet and one is a pilot. More than a few people have accidentally exchanged these with the fuel jets from the bottom of the carb.
2) The diaphragm needs to be in good condition (not leaking) and properly seated during installation. An leakages are a problem.
3) The slide needs to move freely in the carb body. There is a black coating on the slide that can wear off and stick to the carb body. With the low milage, I doubt yours is worn, but you need to make sure it is clean and moves freely.
If in doubt, try running the bike without the airbox and confirm the slide is responding to the vacuum created by opening the throttle. If it sticks you need to determine if it stopped opening because the slide is sticking or because the lack of fuel didn't increase the engine RPM enough to create more vacuum. It becomes a chicken and the egg deal because you don't know where your issue lies, but you are trying to eliminate potential issues at this point.
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