Pair Valve (Secondary Air System) Removal Made Easy

by "Moccasin" Mike

For the C90 Boulevard

NOTE** The only tools you will need for this operation are a pair of pliers, a 6mm hex (allen) wrench, a phillips head screwdriver and a 10mm wrench. These can be found in your Suzuki Tool Kit. (Add a second 10mm wrench if you plan to remove the cylinder studs).

This procedure will take about an hour if you work real slow. J
All metal components of the removal kits have been "Blackened" with satin finish engine paint, and baked at 400 degrees to match your engine block.


The chrome cover is held in place by two allen head bolts. Your bolts may have button caps covering the allen sockets, if so, use a sharp pointed knife to pry the chrome button cap off, then use a 6mm hex (allen) wrench to remove the screws, and pull the cover.


1.) With a pair of pliers loosen and slide the two upper tube hose clamps toward the center of the rubber connecting tubes, and pull the two rubber tubes from the pair valve body.

If you only wish to disable the pair valve, but not remove any of it's components, insert round head screw or golf tee upside down into each lower rubber tubing piece. leave a small piece of the threaded or pointed end sticking out of the the top of the rubber tube (for removal later if necessary), and re-install the tubes to the pair valve and replace the cover.

Continue with Removal
2.) With a 10mm wrench, remove the lower metal tube flange nuts from each cylinder. (4 nuts total) Now you can easily slip the metal tubes off the cylinder studs. Make sure that no gasket material remains on the cylinder flanges.

3.)Remove the three 10mm Box Mounting Bolts (these have big flat washers behind them).

4.) Holding the box loosely away from the engine, reach behind it and pull the rubber air hose loose, either from the back of the valve body or from the plastic connecting adapter just under the side panel (fake tank panel).

5.) Now disconnect the electrical solenoid connection just under the side panel and remove the box and pair valve as a unit.

6.) Pull the remaining section of rubber air inlet hose free from the bottom of the air filter box, paying close attention to where it comes from, then cap the air box outlet nipple with the larger of the two rubber caps from the removal kit. Its a good idea to use the retaining clip on the rubber cap, but you may need to compress it a bit beforehand to give it a snug fit. (you may discard the smaller rubber cap from the kit, as it is not used on the Boulevard models)

7.) Remove the two small gold colored Phillips head solenoid mounting screws, then pull the solenoid and its wire pigtail free from the valve body and box, feeding the wire through from the back of the case as you pull . (The solenoid is a little smaller than a film canister and is bolted onto the outboard side of the pair valve body).

8.) Reconnect the solenoid to the bike's connector, and use the two supplied plastic zip ties to secure it up out of site, behind the side panel. This can be done by looping the zip ties over the main wiring harness and through the solenoid screw holes, then cinch them up to the main harness.

Using the gaskets and plates from the kit, cover the two cylinder ports. Some people prefer to use a little high temp gasket sealer on the gaskets, but it is not a necessity. You may secure the plates to the cylinders using the existing nuts that were removed earlier (and lock washers from the kit), or for a slightly cleaner (but a bit risky) look, you can remove the studs from the cylinders and use the four supplied M6-1.0x16mm (long) bolts and lock washers. See stud option note below.


Use the three supplied M6-1.0x10mm (short) Stainless Steel bolts and lock washers to fill the empty holes in the cylinders left by removing the housing.

YOU’RE DONE!! Don’t you wish YOU could loose five pounds of ugly fat that easy!!! J

NOTE* There are an additional four M6-1.0x16mm Stainless bolts and washers supplied with the kit. These are for replacing the cylinder studs, if you desire to do so.

REPLACING STUDS: If you haven’t pulled studs before; thread two nuts on the stud and tighten them very tightly against each other (opposite directions toward each other), then put a wrench on the inner nut, and as you try to "unscrew" it, the whole stud will unscrew. You may have to apply a little "counter pressure" to the outside nut with another wrench at the same time.

CAUTION! - Bear in mind that anytime you work with studs, you run the risk of breaking the stud off, requiring difficult drilling and tapping to replace it. Pre-soaking the threads with penetrating oil, and a few light taps straight on the end of the stud with a light hammer will help break loose the hold of any corrosion inside. If the stud seems to require a lot of force, leave it be!