Decatting
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Cruiser
Joined: Jun 2006
Posts: 237
Likes: 0
Decatting
Ok here goes have a used head pipe with a cat still inside and will be buying vance and hines slip ons. Do i need to buy a air cleaner also im really confused at this point. thanks for your help slick
Elite HDF Member
Joined: Sep 2007
Posts: 4,928
Likes: 69
From: Near Myrtle Beach, SC
To properly search this forum, consider using Google or any other search engine.
Go there and in the box type hdforums.com cat or hdforums.com decat or hdforums.com stage I or hdforums.com tuning or hdforums.com youfillintheblank
You will see tons of threads related to the questions you are asking. If you have a used header from someone and you don't know what to do with it, these threads will answer your questions.
If you remove the cat, or install an improved aftermarket header, then high flow slipons, you may get away with the stock air cleaner without any change in tune. But it's my opinion that there will be some additional flow and thus your already lean EFI tune will just get leaner (more air, less fuel). If you are going the route of a new header or gutted stock header and new high flow pipes, why would you not add a high-flow air filter and incorporate some sort of fuel management? All of that would complete what is commonly known as a stage I upgrade. The motor will run cooler (more fuel acts as a coolant), with the proper tune your torque and HP will increase several percentage points over stock, and the bike will sound totally different (better according to most opinions).
Several vendors of EFI tuning devices support this forum. You may want to give them a call and discuss your objectives. A vendor that is familiar will just about every legitimate available tuning device, header, air cleaner, and slip-on system is Fuel Moto. FM is a forum sponsor and would be happy to help you with your questions and suggest options.
http://www.fuelmotousa.com/
Go there and in the box type hdforums.com cat or hdforums.com decat or hdforums.com stage I or hdforums.com tuning or hdforums.com youfillintheblank
You will see tons of threads related to the questions you are asking. If you have a used header from someone and you don't know what to do with it, these threads will answer your questions.
If you remove the cat, or install an improved aftermarket header, then high flow slipons, you may get away with the stock air cleaner without any change in tune. But it's my opinion that there will be some additional flow and thus your already lean EFI tune will just get leaner (more air, less fuel). If you are going the route of a new header or gutted stock header and new high flow pipes, why would you not add a high-flow air filter and incorporate some sort of fuel management? All of that would complete what is commonly known as a stage I upgrade. The motor will run cooler (more fuel acts as a coolant), with the proper tune your torque and HP will increase several percentage points over stock, and the bike will sound totally different (better according to most opinions).
Several vendors of EFI tuning devices support this forum. You may want to give them a call and discuss your objectives. A vendor that is familiar will just about every legitimate available tuning device, header, air cleaner, and slip-on system is Fuel Moto. FM is a forum sponsor and would be happy to help you with your questions and suggest options.
http://www.fuelmotousa.com/
Road Warrior
Joined: Oct 2009
Posts: 1,863
Likes: 55
From: Sedalia,Missouri
Do a search on removing the cat from head pipe, it's not hard just takes some time. If your low on funds install head pipe after cat is removed along with the slip ons, this will get you by for a while. You have now removed a lot of the heat caused by the cat.Either now or when you have about $450.00 get you a Power Commander V along with a high flow air cleaner of your choice. This set up will get you by nicely, just remember do not change the aircleaner untill you install the Power Commander V. It's ok to install just the slip ons without the Power Commander.Any other questions call Fuel Motto they will be happy to get you taken care of.
Elite HDF Member
Joined: Sep 2007
Posts: 4,928
Likes: 69
From: Near Myrtle Beach, SC
I will add that there are a couple of methods that guys use to remove the cat from the stock pipe. One method is cutting the header at the midpoint of the cat. Positives with this method include ease of removing the cat. A challenge of this method is to get the pipe welded back exactly the way it was, in both dimensions, before it was cut. Some have reported trouble fitting the header back on the bike if care was not taken in the welding process. One has to consider the amount of metal removed during the sawing process, then you have to keep the two halves in exactly the same orientation. Variances with either of these measurements or orientations can cause minor fitment issues that can turn nasty.
The other method is to cut a "window" out of the header in the area of the cat and remove the cat, then patch weld the metal back into place. This method does nothing to cause fitment or structural issues and in my opinion would be the way to go. Here is a link to some pictures that may help. This is how I would have done it had I kept the stock header:
https://www.hdforums.com/forum/touri...with-pics.html
Seasoned HDF Member
Joined: Feb 2007
Posts: 10,602
Likes: 721
From: Bellevue, NE
I'm confused too. Is this a thread about decatting or air cleaners?
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No you don't need to buy a new ac. Also if you decat it you can get by without a new ac. That said I think the best way is to add a good ac and get a good tuner put on along with everthing else you will be a happy camper you did and you motor will thank you too.
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Outstanding HDF Member
Joined: Sep 2010
Posts: 2,357
Likes: 8
From: Pa
At no point do you "need" to buy an open ac. You can run slipons with or without a cat with no tuner. If you run slipons, no cat, and an open ac then you should get some type of fuel managment. Even Xieds or the adjustable Fl Vieds could richen things up. But if you want performance with the slipons, no cat headpipe, and open ac then you need a tuner. I am running a decatted headpipe, open ac, and slipons with just the (harley installed) stage 1 download and it runs great. I decatted my headpipe with a 1" paddle bit. Took about an hour and its 100% clean. No need to cut the headpipe to get the cat out.
Last edited by pontiac69; Dec 24, 2012 at 10:17 AM.
Seasoned HDF Member
Joined: Oct 2012
Posts: 11,217
Likes: 3,045
From: St.Louis Mo.
drill the cat out useing a 1 inch x16 inch paddle bit,no big deal just noisy doing it and you WILL get all the cat out.slip on's and air cleaner with a set of fl-vied-10 from nightrider .com and you'll be happy for a long time.