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Hello, new here but buying my first vstar tomorrow. 2007 vstar 1100. The previous owner did the single carb conversion on it but still has all the original dual carb hardware. My question is: Should I keep the single carb or put the dual carbs back on and put a pod kit on it. Im looking for the option that provides the most power. Any help appreciated! Thanks
 

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There have been many here try the single carb setup. None ever got it to run correctly in the long run. The two cylinders run at different temps due to one being behind the other one and stock jetting with duel carbs is split for that reason. The one into two intake manifold is known to crack as the two cylinders are vibrating in different directions. These are just a few of the issues. If you have the stock setup I strongly suggest to go that route with pods. Noticed this was your first post, if you post in the New Members Introduction section we can get to know you and your bike.

 

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There have been many here try the single carb setup. None ever got it to run correctly in the long run. The two cylinders run at different temps due to one being behind the other one and stock jetting with duel carbs is split for that reason. The one into two intake manifold is known to crack as the two cylinders are vibrating in different directions. These are just a few of the issues. If you have the stock setup I strongly suggest to go that route with pods. Noticed this was your first post, if you post in the New Members Introduction section we can get to know you and your bike.

Thanks for the help. I picked up the bike today, and already I notice it's having problems. Seems to be starving for fuel with speeds above 50. When I install the original carbs back, is there any special process that I need to follow?
 

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I would suggest to watch several videos to get a feel on h9w the Carb assembly works. While the carbs are off I would suggest to start least take the bowl off and make sure jets are totally clear.


I would also read up on bench syncing so start up will go smoothly. Bench syncing about half way down page.

Did you get the boots and intake also?
 
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You will get different views as to stock airbox and pods. Rideability is probably a bit better with an airbox. Performance and fuel economy is probably better with a full kit for pods (pods, jets, needles, etc...)

I have a Maxair kit on mine and she runs like a beast. But she was running like crap before I put my kit on so I can't speak to the good performance compared to improved performance, with my particular bike.

Make sure you sync your carbs and get the idle right, no matter which route you go.
 

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Hi guys, I have been doing a lot of research about intake and carb setups trying to determine what setup I want on my VStar 650. I'm currently running two into one glass pack exhaust and jetted stock carbs with 105 main jets. It runs well but is a little rich right now. I'll rejet if necessary after my intake is all set up.

I haven't got this all figured out yet but here are some of the things that may be important to consider when evaluating your carb / intake setup:

1) Runner length. Runner is the term used when talking about intake manifolds. I'm not clear if the same term applies when its just a straight run from the carb to the intake port of the head. But what is important about this is the length, especially when you are talking about power. There is an effect that occurs in the intake tube (the runner) where a pressure wave is created as a result of the opening and closing of the intake valve. The timing of that wave is related to the length of the runner because the wave travels back and forth from one end to the other. If the timing is such that the wave is traveling towards the intake valve just before it closes there is a power advantage because there is more air fuel mixture forced into the cylinder. The big question is what is the optimum length? and Do you achieve that length with the single carb set up? this may be significant because the runners on the stock carbs are very short. Short runners are typically good for high RPM's which is contradictory to how the VStar is set up. Peak torque occurs around 3000 RPM. So I'm not sure but it seems like there could be something to gain in the runners.

2) Pods may not deliver more power. The less restrictive the intake the better, but again, the length of the pipe between the top of the carb and filter makes a difference, It's the same issue with the pressure wave. also, the pods tend to have ridges on the mounting hardware, you want smooth transitions all through your intake.

3) An air box may also give performance gains. It stabilizes the air for smooth transition into the intake and it balances out pressure pulses (Helmholtz resonator). With that said, the stock airbox may not be the best airbox because it is also designed to reduce intake noise.

The bottom line is that its very complicated. I think that it's a good idea to run some tests to establish a baseline before you make any changes. Altough, that is difficult to do without a Dyno. Some gauges that I'm using are vacuum measurements in the runners (a higher vacuum measurement is typically better if your intake system isn't restrictive). I have a throttle lock on my bike and I've created a set point so that I can lock the throttle at the exact same position to test my speed with different intake setups, of course that wont work for you if you are swapping out carbs.

Please post any results so that the rest of us can learn from your experience.

Thanks
 

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Everything Damn.It.James said is absolutely accurate.

A motorcycle engine is basically a big air pump. Air in, mix with fuel for combustion and then air out. The more efficiently you can get the air in the better. The more efficient your burn the better. The more efficient the exit, the better.

Smooth surfaces and free flow are what high flow air filters are for. Your jetting (carbs) or your A/F ratio (fuel injection) are what provide your efficiency of burn. Having a free flowing exhaust allows the motor to more efficiently push out the air.

OEM's set the bikes up at the factory for maximum power while minimizing noise and emissions. Those things are not mutually exclusive. To maximize one means to hurt one of the other with OEM restrictions. That's where the aftermarket comes in. Typically a high flow filter breathes better. More air requires more fuel, hence bigger jets or a robust fuel management system for EFI. Now that you've got these big lungs filled, you need to be able to exhale. A free flowing exhaust doesn't have all the turns and chambers and baffles of stock, so the motor exhales easier.

There are a few other subtle nuances to tuning for optimum performance (back pressure, spark timing, etc...) but those are the basics.
 
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