This guide explains how to disable Ducati Secondary Air System (SAS), also know as Secondary Air Injection (SAI), and is valid both for any Ducati Scrambler with 800cc engine (Icon), but also for the Monster 797 and 797 Plus, which install the same engine.
The Secondary Air Injection system temporarily throws fresh air from the air box to the exhaust valve of both cylinders, in order to burn any excess of unburnt gasoline which might still be present on the exhaust gases after combustion. The main purpose is to avoid damage to the catalyzer. This bypass valve is electrically actuated by the ECU of your Ducati, and it's driven "open" (air flows to the exhaust) just in case of releasing the throttle, or at low engine loads (for example during gear shifting or slowing down).
If you installed an aftermarket exhaust, such as a Termignoni, Akrapovic, SC Project or similar, most probably the catalyzer is not present anymore, so there's no need of having a SAI anymore. In addition to that, on "free flow exhausts" (no catalyzers), the SAI causes a noisy popping when releasing the throttle, due to the fact that part of the gasoline burns close to the exhaust valves, or inside the exhaust pipe. This noisy pops are probably not good for the engine, and honestly, I don't like them. So, the solution to avoid such noisy popping is to disable the SAI.
Before I explain how to do it, let me tell you that this modification is not legal (as putting an exhaust without catalyzer is illegal too), so do it at your own risk. I won't be responsible for that. So, do it only when you are riding in a circuit, i.e. not on public roads.
The first step to do is to remove the right cover. There are 2 screws which have to be removed with an hexagonal wrench. Then, remove the 2 connectors of the voltage regulator. And remove the cover from the bike.
The next step is to loosen the clamp which locks the hose to the air filter box, and remove the hose. In my case, the clamp was somehow hard to remove by hand, so I suggest to use a tool like a plier or similar (see the last picture to understand which tool should be used).
To better understand how the SAI works and where it's located, you can have a look at the following pic. The Secondary Air valve actuator is behind the red frame and cannot be seen completely, however you can see its 3 hoses (1 from the air box, 2 to the cylinders) and the electrical connector.
The following picture shows the connection for the hose. In order to avoid air flowing from the airbox to the exhaust, you should cover this point with something which stops the flow of air.
In order to stop the flow of air, you can simply used some tape. This solution is cheap and effective.
For redundancy, as an additional countermeasure against the flow of air, you can also put some plastic sheet inside the hose.
Finally, the last step is to fit the hose again to the air box connection point, and put the clamp to the original position. Make sure to do this job well, because otherwise some "dirty" air from outside could flow to the airbox (this is very dangerous for the engine) or to the exhaust. However, this worst case would happen only if either the tape or plastic sheet has a leak.
The modification requires about 30 minutes in total, because the clamp is in a position which is hard to access. If you are lucky, or are expert, 10 minutes might be enough. After this modification, the popping issue was quite solved, there was just some little and not noisy pop very rarely.