Found out the electronically controlled throttle plates on my 08 Vulcan 900 have been removed by the previous owner. Has anyone removed them or have an old throttle body I can scavenge? I am getting my ecu back from Ivan and his tune accounts for them being there. Might not even notice but I would like to have the plates back on regardless.
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That’s the secondary that has been removed. It’s not an uncommon mod. Very misunderstood though. I’m only going to give the short and dirty version.
People mistakenly believe that because the secondary is slow to open at lower rpm that it starves the motor of air. It’s designed to work this way. You give it throttle from a stand still…ecu says oh crap he wants to move..ecu determines you are at lower rpm and so only partially opens the secondary (although primary is wide open) Because it knows that you are basically sitting still or near idle and that very little air is being pushed into motor. Partially opening the secondary creates a smaller opening and increases the velocity of the little air available. Once you get up in rpm’s, the secondary opens all the way. it probably feels a little snappier on take off but in actuality you have lost a tiny bit of torque low in the rpm’s. It also probably idles a bit rough compared to a factory set up. You might not notice much unless you rode a factory correct version after being used to yours. I’m not sure what mods Ivan made to when the secondary opens and how much at what throttle input point. Call and ask him if missing secondarys will affect the tune. He has likely gotten the question before.
People mistakenly believe that because the secondary is slow to open at lower rpm that it starves the motor of air. It’s designed to work this way. You give it throttle from a stand still…ecu says oh crap he wants to move..ecu determines you are at lower rpm and so only partially opens the secondary (although primary is wide open) Because it knows that you are basically sitting still or near idle and that very little air is being pushed into motor. Partially opening the secondary creates a smaller opening and increases the velocity of the little air available. Once you get up in rpm’s, the secondary opens all the way. it probably feels a little snappier on take off but in actuality you have lost a tiny bit of torque low in the rpm’s. It also probably idles a bit rough compared to a factory set up. You might not notice much unless you rode a factory correct version after being used to yours. I’m not sure what mods Ivan made to when the secondary opens and how much at what throttle input point. Call and ask him if missing secondarys will affect the tune. He has likely gotten the question before.
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