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As promised, here is my Caddman Air Mod tutorial. I take no credit for thinking this up, nor do I take credit in figuring it out myself.

If you want to get straight to the install, skip the next section, as I am going to ramble on a bit with my intro.

Introduction / Theory

Before continuing, I would like to explain what my plans are and why I am doing this, as this mod may not be for everyone. What this mod will allow you to do is install a 9” round air cleaner that can be bought at many auto parts stores on both sides of your bike. Having these air cleaners on your bike is an alternative to the many aftermarket cold air kits available for the Vulcan motorcycle. While there is nothing wrong with any of those aftermarket kits, there were a couple things I didn’t like about them.

1. They aren’t symmetrical. When you install a Tornado or Hypercharger kit, it only mounts on one side of your bike. That leaves a big bare spot on the left side of the bike. Some people fill up this area with other things, but nothing quite looks as good to me as symmetry.

2. All of the aftermarket air systems protrude out more than the stock air cleaner and can get in the way of your knee. Some are worse than others, but I prefer something slim and not obtrusive.

3. Lastly, all of the aftermarket systems are quite expensive for what is essentially just an air filter and some tubing. This mod can be installed for less than $50.

My bike currently has a Vance & Hines Big Shot exhaust installed. It is a well known fact that in order to get full advantage of an aftermarket exhaust on Vulcan cruisers, you need to compliment it with a high flow air kit, and once you do that, you need some sort of electronic modification to your bike’s computer to adjust the fuel curves as the bike already runs dangerously close to lean from the factory. Many people complain about pinging on their stock Vulcans, and although the stock pinging isn’t anything dangerous, once you start pumping in more air into your engine, you could push it over the edge, so you do not want to do an air modification like this without somehow changing your fuel mixtures on the bike.

There are several choices for products that can change your fuel curves on your bike, but like the aftermarket air systems, they can get a bit pricey. Gadget’s site also mentions adding a resistor inline with the air temp sensor that allows you to ‘trick’ the computer into richening up the fuel mixture. Although this is a very primitive and non-exact method, it is essentially the same thing as what those aftermarket products do.

The resistor mod only applies to fuel injected bikes. If you have a carbed bike, you will need to manually adjust your carberators using new jets.

Although this modification is almost free (the only part you need to buy is a resistor), it does involve going a little deeper into the electronics of your bike and soldering a resistor into the stock wiring. Some people may find this scary, but I wanted to try it, so for this walkthrough, I am soldering in a 680 ohm resistor into the wiring harness coming out of the air temp sensor. If you already have a Power Programmer or a comparable product on your bike, you can skip this whole step, but since one of the points of the Caddman mod is to save money, you can try this to nearly accomplish the same thing.

I also am choosing not to completely remove my reed valves as my bike is still under warranty, and I want all these mods to be quickly removable, so I want to leave my bike as close to stock as possible. You can accomplish turning off the reed valves by shoving a marble up into the reed valve hose. I plan on doing this and will show this step during my walkthrough as well.

So anyway, onto the instructions.

Parts Needed

(2) Spectre 9” x 2” round air cleaners and filter. The part number for what you need is 4770. The replacement filter is PN #4805. When you buy the first air cleaner, it comes with a filter, so you wont need to buy a new one until its time to replace it. There are other brand filters you can use in place of the Spectre paper filter. Its up to you to find another filter to use if you want. As long as its 9” round, it should work. I was able to find these filters at Auto Zone and they were $19.95 each. You will only use the filter and filter lid in this kit. The backing plate that comes in the packaging can be discarded.

(2) 8mm x 1.25 pitch studs approximately 35-38mm long. I was able to find these at a local Ace Hardware store. They’re not a national chain like Home Depot or Lowes, so if I was able to find them there, you should have no problem at a national chain. If you cannot find a stud in that size, any long 8mm x 1.25 pitch bolt will work as long as you cut the head off and make it approx 35-38mm long. The length isn’t crucial, but if you make it too short, it wont reach through the filter lid, and if its too long, it will bottom out on your filter nut.

(2) 8mm x 1.25 pitch acorn nut. You don’t have to use an acorn nut. A wing nut or a regular nut will work well. There are also nice air filter nuts that you can use, as long as theyre the right size and pitch. It doesn’t matter what you use as long as it fits.

(1) 1/8” sheet metal screw. This screw will be used to plug a hole, so its size isn’t too important. If you have a jar of screws lying around, I’m sure one will work fine.

(1) Toy Marble. You can even use the decorative kind you often find in the bottom of flower vases. Optional

A tube of silicone sealant. Optional.

Some scrap metal or tin and something to cut it with to make a block off plate from. Optional.

500-1k Ohm 1/4watt resistor. Optional.

Electrical tape

1,058 Posts
Discussion Starter · #2 ·
Installation – Right Side

Step 1:

Once you have everything ready, you need to remove the air cleaner covers off both sides of your bike. They are held on by an allen bolt. I didn’t pay attention to which size it was, I just have a ton of them lying around so I found one that fits and removed the bolts. You won’t reuse the bolts, but you’ll want to save the washers.

Here is the right side of the bike with the cover off.

Step 2:

Next, you’ll need to pull both ICS (Idle Control Solenoids) off their tabs. They are not held on by anything other than friction from those rubber ‘ears’ (indicated by the YELLOW arrows) that surround them. Just pull both sides of each one and they’ll come off.

Step 3:

After you have both solenoids off, you’ll need to bend each of the 4 metal tabs inward about 1/8th of an inch. The only reason you bend them is to give your new air filter a little more room on the outer edge. The tabs are made of a soft metal and bend easily with just hand pressure. You do not need to bend them much as you still want to remount the ICSs later. (You have the option to not reinstall the ICSs, but more on that later.)

Step 4:

Next, pull both of the ICSs off their tabs, and you’ll see the rubber hose that goes to the Reed Valves behind the front ICS. This rubber hose is indicated by a RED arrow, and is where you will shove your marble if you intend on blocking the reed valves. Some of you may have already disabled your reed valves, so this hose would be missing if they were removed, but for an installation like mine that needs to be easily revertible to stock, I am leaving this in place.

If you are planning on doing the resistor mod, don’t plug the hose with the marble yet, as you will need to remove this hose pretty soon.

Optional – Doing the Resistor Mod

Once again, you do not need to do the resistor mod if you already have an aftermarket tuner like a Power Programmer, FI2000, or some other mod on your bike. You also do not need to do the resistor mod if you have a carbed bike. This only applies to fuel injected bikes. If you do not have these, you will definitely want to add the resistor as doing an air mod like the Caddman mod can make your bike run dangerously lean. If you are skipping the resistor mod step, jump to Step 12.

Step 5:

The resistor needs to go inline with the air temp sensor, which is behind the right side filter backing plate. In the following picture, the tip of the air temp sensor is indicated by the YELLOW arrow.

To remove this backing plate you will need to remove the four allen bolts surrounding the throttle body opening as indicated by the RED arrows. You will also need to remove the GREEN hex bolt, and both BLUE Philips head screws.

Step 6:

Once all 4 allen screws, the hex bolt, and the two screws are removed, you’ll also need to remove the PURPLE hose clamps on both of the hoses right under the throttle body. You just need a pair of regular pliers to squeeze the tabs on the hose clamps and pull them down the hose and you can then slip the hoses off their connectors which go behind the backing plate.

You’ll also need to pull the BLUE reed valve hose through the backing plate. In this picture the front ICS is blocking it, but it’s behind it. You can see a better picture of this hose in the picture in Step 4.

Lastly, you’ll need to pull the YELLOW drainage hose out. There is nothing but friction holding this on, so work your hand back there and yank it out from behind.

I drew a RED arrow to the wiring harness that goes through a grommet to the back of the backing plate. You will not be able to easily remove these wires, so just leave them be. You’ll be able to completely turn around the backing plate so you can see the back of it without these wires getting in the way.

Step 7:

Now that everything is disconnected and out of the way, you’ll be able to completely turn around the right side backing plate so you have access to the air temp sensor’s wiring. The harness is indicated by a PURPLE arrow.

Strip away some of the stock electrical tape going around the wires. There are two wires going into the air temp sensor. One is pink and one is brown. The one you’ll want to work with is the pink one.

Step 8:

Now the next step involves soldering a resistor inline with this pink wire. Choosing what resistor is right for you is up to you. I recommend reading the following article at Gadget’s site:


This article talks about why the resistor mod is done, and how the Vulcan’s ECM (Engine Control Module) interprets what it receives from the air temp sensor. Essentially, as the outside air temp is colder, the air is denser, so the ECM reacts to that by adding more fuel. If you trick the ECM into thinking the outside air is colder than it actually is, the ECM will respond by sending more fuel into the engine. Normally this could cause any engine to run rich (too much fuel, not enough air), but since our engines run close to lean from the factory, and we are adding an air mod which is putting MORE air into the engine, we want more fuel to balance things out again.

There is no correct resistor value for what is “right” because the “right” resistance varies upon the actual outside temperature. It is commonly believed that any value between 500 and 1k ohms will work. The best thing to do would be to install a potentiometer (variable resistor) which has a dial that allows you to vary the resistance to find the correct resistance. I was unable to find a suitable potentiometer at my local Radio Shack, so I took a stab in the dark and went with a 680 ohm resistor. If I determine that my bike is still running lean after the install, I can swap that for a higher resistance resistor, or I can go with a lower resistance one if I find myself running too rich. Like I said before, the actual value you use is up to you, but it’s probably better to err on the small side rather than put in one too big and cause your bike to dump too much fuel into the engine.

Now that we got that out of the way, get out your wire cutters and make a snip in the pink wire. Don’t cut it too close to the plug or else you won’t have enough wire to solder on. Once you have your cut made, strip about ¼” of insulation off both ends of the wire, and solder your resistor in place. Resistors are NOT polarity specific, so it does not matter which way you put it. Another word of caution is although resistors don’t easily get damaged from heat, don’t keep your soldering gun on the wires for too long as too much heat for too long will damage the resistor.

Step 9:

Once the solder resin has cooled, give it a couple tugs to make sure your soldering is good and that it will not come apart. The next picture is a bit blurry because I couldn’t get my digital camera to focus properly, but this is what your resistor (PINK arrow) should look like when you’re done.


1,058 Posts
Discussion Starter · #3 ·
Step 10:

Next, carefully wrap the exposed wire with electrical tape, and reconnect your wiring harness to the air temp sensor.

Step 11:

Reinstall the backing plate onto the motor and be sure not to pinch any wires. Make sure you get all the vacuum hoses correctly hooked back up, and reinstall the 4 allen bolts, the two Philips screws, the hex bolt, and both hose clamps. Once you have it back together, if you are using a marble in your reed valve hose, stick it in now. The marble I got was a bit too small for the hose and would keep falling out, so I wrapped it in several layers of electrical tape and shoved it up in there nice and tight.

Step 12:Optional

Before putting everything back together, you might want to disable your ICS valves. There are mixed opinions on the Internet about what good this does, but most everyone agrees that it doesn’t hurt to have them disabled. They are there to stabilize your idle and could possibly improve fuel economy slightly at idle or near idle speeds, but once you get going, they don’t really do much, and end up just making more noise. Since the Vulcan motors are noisy beasts to begin with, you might want to try disabling them. You can either completely remove them altogether, or you can just unplug the green wires going into them. I chose to unplug them.

If you do choose to totally remove the ICSs, make sure to plug both vacuum tubes going through the backing plate, or else you’ll have a big vacuum leak when your bike is running!

There is a green wire going into each of the two ICSs. Unplug them and leave the prong RED arrow disconnected.

Once you have both sides unhooked, you’ll want to tie up the loose wires as you do not want them making contact with anything metal in there as that will short out your ECM. The original walkthrough said to use wire loom to cover them up, but I just wrapped the ends in electrical tape and tied everything together.

Step 13:

Now all you need to do is slip the ICSs back onto their tabs (assuming you didn’t remove them), insert one of your 35-40mm studs into the air filter cover bolt hole and install your new Spectre air filter onto the right side of the engine. Reuse the original washer under your acorn nut to give it a snug fit.

Installation – Left Side

Step 14:

The left side of your engine is a little less involved and can be done one of two ways depending on which filter you use. Like the right side of the engine, remove the filter cover allen bolt and put it somewhere. Save the washer for later use. Once you get the left side cover off, you will see the filter. It is just held on with friction so pull it off.

Once you have the cover off, remove the two RED Philips screws, and the two YELLOW hex bolts. This will allow you to totally remove the left side backing plate.

This is what the left side of the engine looks like with the left side backing plate removed. You’ll notice the black plastic duct that runs through the center of the engine. This is the pathway that ALL the air that your engine uses must run through. In order for your engine to breathe, it needs to go through a 180 degree turn, through the air filter, through this tiny tube (which isn’t even straight), then to the right side of the engine, then around another 180 degree turn to get into the throttle bodies. No wonder the Vulcans respond so well to air mods - they’re being choked from the factory!!

Step 15:

Remove the two Philips screws at the top of the left side backing plate to remove the snorkel at the top.

If you are going to be using the K&N filters or anything thicker than the stock Spectre filters, you can just reuse the stock filter and put it inside the new filter. The original filter will fit inside the new filter, and by doing that, you are not required to make a block off plate for the snorkel. The stock filter is just a tad too thick to fit under the lid with the original 2” Spectre filter. I tried to put it in, and it barely fit, but was putting a lot of tension on the outer lid and I was afraid it wouldn’t seal properly, so I chickened out and didn’t use it. Don’t worry about having two filters on the same side of the engine as with this Caddman mod, the majority of the air will come from the right side of the engine anyway. Having a filter on the left side of the engine is really just there to balance out the looks of the mod.

You could even get away with not putting a Spectre filter on the left side of the engine at all. It just might look goofy with having a stock air cover on the left side and a round air filter on the right side, but it’s your bike, and you can do with it whatever you want.

If you are using a thicker filter and are going to reuse the stock filter, you can skip to step 18, and just install your stud and new filter and reassemble with the new filter lid.

Step 16:

After removing the snorkel, you’ll need to get your scrap tin or metal out and begin to cut a block off plate. If you don’t block this off, you will be sucking in unfiltered air into your engine which could damage it.

There is no science to this next step, just use your cutting tool of choice and cut a piece of metal that roughly fits over the hole and screw holes. You will also need to drill a pilot hole into the metal so the screws can go through it to hold it into place.

Here is a pic of one of my attempts at a block off plate. The plate you see in the pic ended up being too small in one corner, so I had to recut it, but you get the idea. You’ll also want to use some type of silicone sealant on the gasket to keep it from vibrating loose.

A warning about silicone sealant is that if it gets sucked into your engine, it could clog vital components like your fuel injectors and such. Silicone sealant also doesn’t like fuel, so keep it away from any fuel and make absolute sure that it is dry before starting up your engine.


1,058 Posts
Discussion Starter · #4 ·
Step 17:

Once you have your block off plate cut and new holes drilled, use the original screws and mount it back to the left side backing plate. I used some more silicone sealant around the edges and on the screw threads to eliminate any possibility of a leak.

You’ll also want to use a sheet metal screw BLUE to block the drain plug at the bottom of the backing plate. This is the screw I mentioned in the parts list at the beginning of this walkthrough. Any size that fits will do. Just find a spare screw you have lying around your garage. If you are using a thicker filter and reusing the original filter, you do not need to plug this hole.

Step 18:

Once the silicone is reasonably dry, remount the backing plate with the two Philips screws and two hex nuts. Thread in your other 35-40mm stud into the air cleaner bolt hole and reinstall the air filter and lid.

This is what the left side looks like with everything back together.


Unfortunately, the day I installed this, it was raining, so I still haven’t been able to take the bike for a ride, but I did fire it up, and it sounded a lot meaner. The exhaust somehow sounded deeper, and made my Vance & Hines pipes bark even deeper. The bike did appear to have a rougher idle, but in all fairness, I didn’t let it completely warm up. It didn’t stall and had no trouble starting. I will update this section in a couple days after I’ve had some time to ride the bike and get some on the road impressions.

Although there are a number of ways to do this mod, it’s really not that hard. Some people might be scared soldering, but if you have an aftermarket tuner, you don’t need to worry about the resistor mod. If you go with the K&N or some other thicker filter, you can skip the block off plate steps.

I REALLY like the look of these filters installed. All the pictures I’ve posted don’t do it justice in person. It reminds me of a custom look that a hotrod shop would have built. I personally think it adds to the “muscle” look of the Mean Streak, and since its an effective mod as well, all that’s all the better. I got all these parts for less than $50 and the install took me about 3 hours to do, but that involved taking all the pictures for this walkthrough.

Some people ask if its dangerous to have those filters exposed like that. They say, won’t they get damaged if they get wet? Well sure, any filter isn’t supposed to be exposed to water, but all of the other aftermarket air mods have exposed filters so this is no worse. Compared to the Tornado mod, which involves a single cone filter protruding out of the right side of your engine, I’d say this mod is even safer since these filters tuck nicely into the engine and are shielded a bit more by the bike.

You obviously wouldn’t want to get caught in a big storm with these installed, and you will want to take care to not get them wet when washing your bike, but that’s just common sense if you ask me.

Heres a couple more pictures of the filters installed. Like I said, they do not do the bike justice.


151 Posts
Very nice, great pictures and instructions. Even a dummy like
me should be able to follow and do it too.
Please keep us up to date on the test ride and results, specially
on the gas milage.

372 Posts
Beautiful job with the caddman instructions. Am going to install it this winter on my Mean Streak. Was going to buy after market but your bike looks sweet with those dual air cleaners. Thanks again for your time and effort. You saved me and probably a bunch of people alot of money!

60 Posts
Excellent work with the tech article! This is a mod that I had seen on Gadget's site, and your effort makes it easier to understand. Of course that also means I'll have to get busy gathering all the necessary parts to do the work on my Meanie. Thanks again.

1,058 Posts
Discussion Starter · #12 ·
Thanks for the kind words everyone. I do this for the whole community and its good to see people appreciative of it.

Update: I put about 80 miles on the bike today and as predicted, the bike definitely responded well to the mod. As mentioned earlier, it starts everytime, it hasn't stalled, no FI or temp lights or anything odd to report other than a slightly rougher idle, which is to be expected.

Off the line power is definitely improved. It seems to have a "snappier" throttle response, and upper midrange to upper end power is definitely improved. On the highway, I can accelerate from 70-90 mph much easier than I could before.

The bike seems to have lost some of the flatness in the power band that it had above 4000 RPM. By no means is it a high RPM screamer, but for a big V-twin, I'd say the top end power is definitley improved....by how much, I can't tell.

It's definitely noticeable...although don't think this transforms your bike into an all new machine. It basically lets loose a couple extra ponies that were being kept back in the stable. The Mean Streak is a little less unmean now.

Highly recommended!!!

558 Posts
I did it, took a whole hour, I needed to rejet I put in a 140 from a dynojet kit. So far no popping. i need to ride it a little more to know more, but it's kinda raining here. I will keep posting on this mod. For those who are wondering I didnt do anything with the left side its all stock including crossover tube. If I need to convert it back , all I have to do is put stock cover back on.

123 Posts
Hey, guys,

Member GCL from motorcycle-usa.com sent me a link to this page, and I had to register here just to say how wonderful the how-to thread came out.

I gave up the white paper filter elements, and bought some blue cloth Spectre elements that are K&N clones, and the performance is even better.

They came from Pep Boys ($16 each) and I oil them with Fram Air Hog filter oil from Wal-Mart (kit with oil and cleaning fluid-$12.)

I'm just jazzed at how many guys are doing my mod since I first developed it. There were several Vulcans at the High Sierra VROC rally running this mod, on Nomads, 1500 Classics, and 1600 Classics.

I'm the head mod at the MC-USA forums, so I don't have much time to post on other forums, but I'll try to drop in from time to time.

2004 Nomad 1500 "Baggins"
VROC #11619 Rolling Blunder #128

1,058 Posts
Discussion Starter · #16 ·
Wow, my little walkthrough got the attention of the man himself!! :D Feel free to post this walkthrough on any site with people who can benefit from it. My work is for you guys, so spread the love! :D

Living on the dark side
2,541 Posts
I think I may have already put out this warning somewhere on this forum, but I had bad luck with the spectre brand cotton filters. I went with red as opposed to blue, but both of mine began to crumble on the black rubber edges on the first ride. Could've easily had fragments get into the engine but luckily I found this fault after the first ride. I lightly pushed on them with my finger and the edges just began to fall apart. I'd spend a couple extra bucks and get the real K&N 9x2" filters. They're about 36 bucks a piece. Maybe I just got two from a bad batch, but I just thought I'd better give a heads up.

1,058 Posts
Discussion Starter · #19 ·
Rocsmeanie said:
Sorry but I just don't see how it opens it up???
The crossover tub is still there and used to get the air to the throttle bodies.

Your throttle bodies are on the right side of the bike. The air will get sucked into your engine using the path of least resistance, which means that almost all of the air that gets sucked into the throttle bodies will now come from the right side of the bike, as opposed to stock where it comes from the left, and has to go through the cross over tube.

Although the crossover tube is still in place, it is basically not used anymore. You could do this whole mod without even putting a filter on the left side and blocking off the crossover tube altogether and you would be getting about the same amount of air. Having the crossover tube still in place is just there to make it easy to install, and having the filter on the left side is just there for looks.
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