For Classic, Nomad & Drifter FI models
These instructions will help you remove the reed valves and associated hoses, stock air filter and starter solenoids and replace them with an aftermarket air kit such as those offered by Bad Ace Billet, Thunder Manufacturing and Barons. When replacing the restrictive stock air cleaner it is generally recommended you install an aftermarket computer such as a Dobeck Performance TFI or Power Commander to prevent the engine from running excessively lean. You'll find installation instructions and other information for the TFI here.
It is strongly recommended that you read these instructions all the way through first and locate the components identified. In reading you will discover there is sometimes more than one way to reach the same goal and you can choose the way you think is right for you.
While covered here, removal of the reed valves and air switch is not mandatory. It is your option to remove or keep in place and functional.
Installation of an aftermarket air cleaner is a simple process if what is being done is understood first.
Terms used in the following instructions:
Idle Control Solenoids: Electrically enabled solenoids which pump air into the throttle body for stable idling during warm-up. Located under right side cover you can't miss them, they make one heck of a racket when the bike is first started.
Reed Valves: Allows air to mix with unburned gases leaving exhaust valves and causes popping sound in exhaust. Located inside rectangular boxes attached to each cylinder.
Air Switch: A vacuum enabled “switch” which receives filtered air through the starter solenoid backing plate and sends to the reed valves. Located on top of front cylinder.
Throttle Body: Receives filtered air which is used for combustion.
Left Side: “Clutch side”
Right Side: “Brake side
- Aftermarket air cleaner of your choice. Make sure it comes with a proper adapter plate for your bike.
- Coasters if you'll be removing the reed valves. These are available from several sources including
Tools and supplies needed:
- Tin snips, Dremel tool or home made 'hot knife' to remove cross over tube.
- Metric Allen wrenches, ¼” drive ratchet with metric sockets, open end wrenches.
- Needle nose pliers to remove clamps and to loosen hoses as they tend to stick on nipples.
- Cable ties also known as zip ties.
- Tape or shrink tubing that will withstand engine heat. (cheap, black electrical tape not recommended)
For removal of all parts mentioned above you will remove the seat, gas tank, instrument cluster, left and right side air filter (left) and cold idle solenoids, reed valves and associated hoses. With reed valve removal you will remove the air switch which sits on top of the front cylinder and disconnect the vacuum line from that switch to the throttle body. You will install “coasters” to plug the reed valve’s access to the exhaust system.
If you are only installing an aftermarket air cleaner and not removing the reed valves there is no need to remove the gas tank so you can skip to #4.
- If you are removing the reed valves and installing coasters, remove the gas tank according to Gas Tank Removal For F.I. Vulcans..
- Remove the air filter housing and backing plate on the left side. If you have a California Vulcan there will be a vent hose connected to the backing plate. That's coming from the charcoal canister under the left side cover. You can completely remove the hose disconnecting it from the canister or tuck it out of the way. When all parts are removed all you'll see is the crossover tube going to the air box backing plate on the right side of the bike.
- Remove the air box cover (just like the air cleaner cover) on the right side and remove the screws and bolts holding the backing plate to the throttle body and air tunnel. Disconnect the rubber hoses connecting the cold idle solenoids to the metal tubes. Pull the backing plate away from the bike so you have room to remove things.
- Disconnect the four wires that connect to the solenoids and cover them with shrink tubing or something suitable so there is no way they can ever touch metal. If they do you'll be replacing the bikes main fuse. Using a flat blade screwdriver push the rubber grommet the wires pass through out the back of the backing plate and pull the wires all the way out.
- Disconnect the crank case vent hose from the bottom of the backing plate. Disconnect the hose that feeds air into the air valve switch located on top of the front cylinder. Some aftermarket air cleaners like Thunder's "Hypercharger) require you to disconnect the metal pipes that go under the throttle body and are connected to rubber hoses on top of the throttle body. Most do not. Check the manufacturers instructions for that option.
- If you are not removing the reed valves skip to item 9. If you 'are' removing the reed valves and replacing them with coasters (metal plates) read about the Coaster Installation.
- Crossover tube removal
You have a couple of options here. Some hacking the tube to bits with the tin snips while others cut the ends off with a Dremel cutting wheel. The less messy method is shown here.
- Find a piece of thin flat metal (thinner the better). File or grind the edges to a 'V'. The 'V' cut helps when you hold the metal off center so as the plastic cools it won't grab and stop forward motion. With a propane torch heat the metal bar until it begins glowing then insert it in the air tube. The hot metal will cut through the tube easily but don't breathe deeply, there will be lots of smoke and toxic plastic fumes in your lungs if you do. Heat the metal bar as many times as necessary.
- A similar but maybe even easier option using a heat gun comes from "is0" on riderforums.com. (Start by cutting off the left flange).
I basically just aimed the heat gun straight into the crossover tube and let it do its thing for about 3-4 minutes. Then, I went to the right side of bike, grabbed the tube with some channel locks, twisted and pulled. It came out with very little effort.
At this point, everything should be removed so lets put the new stuff on.
- If you removed them install coasters on the front and rear cylinders where reed boxes were located. You can re-use reed valve box gaskets if not destroyed or a sealer if desired but a gasket or sealer is not absolutely necessary. Plug the throttle body vacuum nipple as detailed on the reed valve removal page.
- Tidy up the wires from the cold idle solenoids and zip tie them to the throttle cable bracket away from anything that could chafe against them causing a short. You might want to stuff the entire bundle of wire into a large shrink tube for extra protection.
- Install the (brass colored) air temperature sensor in your new adapter plate and attach the plate to the throttle body using supplied bolts.
- Attach the crankcase vent hose to the nipple supplied with your new air cleaner (there will be a hole drilled for mounting). Attach the filter backing plate, filter and outer cover.
- If you removed your tank for R&R of the reed valves replace the tank in the reverse order you removed it. Note your clock will now have to be re-set.
You're done! If the left side of the bike now looks a little naked there are lots of options for covers. You'll find a few shown on this Fixit page. Note that after removing your idle-control solenoids you may have to pull the fast-idle knob on the left, behind the radiator, to keep the bike idling when it's cold. Resist the temptation to adjust the idle upward as it should speed up on its own as the bike warms up.