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Discussion Starter #1
hi everyone i'm new to this web site, but i had just bought a 2003yamaha v star 1100 classic and i'm not very smart about the motor. so my question is the bike has cobra longboy exhaust on it and i had taken the baffles out because the sound it makes without them is so sweet. now the old owner said he had rejetted it for the pipes but how do i know if taking the baffles out will hurt the motor what signs should i look for or should i not worry about it. thanks for any answers. josh
 

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It should be alright , but just to be on the safe side run it for a week or so and check your plugs. If it is running too lean your plugs will be a very light color. They will look too clean.
 

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I agree!

It should be alright , but just to be on the safe side run it for a week or so and check your plugs. If it is running too lean your plugs will be a very light color. They will look too clean.
I agree if its running too lean, they will look white, kinda chalkie looking. What your looking for is a tan to brown color on the plug, and if they are black it means your running too rich. Good luck, I just did a modification on the airbox on my 1100 custom and it lean it out some so I had to close off the old air intake port in favor of the new port I put in the front of the airbox. My plugs were showing signs of chalkie look, so I had to close off the old air intake port.
 

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Discussion Starter #4
thanks for the advise i have checked the plugs after a long ride today and they are a tan/gray color what do you think i should do.
 

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I would leave it alone!

thanks for the advise i have checked the plugs after a long ride today and they are a tan/gray color what do you think i should do.
I would leave it alone for now, but run it for awhile and check them again. The gray color might be a sign that its a little lean, so for now I would run the way it is, and say check them again in 2-3 weeks. if they are the same. I would say leave it alone.
When mine is running okay, it is a tan color.
Bob aka busterrm
 

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I'd be really surprised if you didn't need to rejet after removing baffles. You're opening it up to a LOT more airflow.
 

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Your exhaust is gonna get out faster, but your air isn't gonna speed up on the intake side. More Air needs more Fuel, No More Air means no jetting change. If your bike was running well before, it will be fine after removing the baffles. Use a mirror and check to see if your PMS screws have had the brass plugs removed, to point you in the direction of if a jetting change has been made. Most pipe companies want to sell you a jetting kit because its maybe $20 in parts and $75-$100 in cost to you. Do the math. Check out this chart

http://www.sloneservices.com/SilverBack/VStar1100-FAQ-05.htm#Pod-Jetting-Specs
 

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From what I have seen of the aftermarket pipes and the baffles installed they are free flowing to begin with. Removing the baffles should not cause much change in the fuel\air mixture that would require a rejet. See how the bike runs before deciding to rejet.
 

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I did the same with my shotgun pipes, I didn't need a re-jet after removing the baffles because they actually caused no restriction. If you can see all the way through your baffles like mine, I'd say you don't need a re-jet either.
 

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I know for a fact I've been told that you can remove the first baffle and be ok, but any more than that (especially a full gut) and you've got to rejet.
 

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Does back pressure mean anything to anyone?
Actually there are a few myths about back pressure but maybe I can clear why back pressure is not really an issue at all. First off you don't need back pressure at all to make an engine work properly. However exhaust diameter is what is key in losing or gaining power through your exhaust.I will use a v-twin just to simplify my explanation. Your first cylinder fires and sends the exhaust out of engine and down the exhaust and at some point that exhaust gas is going to pass the opening of the header from the second cylinder.(2 into 1) Now when this happens the gas should be traveling fast enough when it passes by that it creates a vacuum in the the second cylinder header helping to draw out the exhaust gas from the second cylinder. (this is called scavenge) Now if the diameter is too large then it will not have the velocity it needs to scavenge the exhaust from the next cylinder. If the exhaust diameter is too small the exhaust will not be able to exit the cylinder fast enough because it is too restrictive. So what I am saying is that pressure has nothing to do with it and velocity has everything to do with an exhausts performance. This is why you will always get better performance from a 2 into 1. You will not get scavenge from 2 into 2 because the exhaust exits into 2 separate pipes. It works much like an old paint gun. the air rushes past an opening and draws the paint out. Now I can guarantee this will stir up some controversy because somebodys great grandpa told his grandpa who told his dad who told him that you have to have back pressure to make it work right, I'm sure his great grandpa was a great man , but he was wrong.
 

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Discussion Starter #14
i want to say thanks to everyone for there help the bike still runs good just as long as it stays that way but i will keep an eye on the plugs and it sure does sound mean with no baffles and you can tell i did lose a little power in the mid range. but do i want power or sound and sound won. thanks again guys
 

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i want to say thanks to everyone for there help the bike still runs good just as long as it stays that way but i will keep an eye on the plugs and it sure does sound mean with no baffles and you can tell i did lose a little power in the mid range. but do i want power or sound and sound won. thanks again guys
you probably lost a little torque in the mid-range but picked up a little hp on the top end, so you didn't really lose any, you just moved it around.:D
 
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