The owner of this KTM Adventure was a nice bloke who didn’t come in for the usual snatchy throttle sort out. He’d changed the airbox – actually removed the stock unit and fitted a DNA filter in its place – and in the process created some problems. The bike was running really rich with horrendous fuel consumption…

It’s important to understand how the air works around a motorcycle and how the engine draws it in. By removing the structure of the airbox he’d also removed the engine’s lung, in effect. We took our time to go through all this, and also explained that during the ECU remap we’d had to take a load of fuel out because the airbox was gone. Far from increasing airflow – which he’d thought would happen – and the engine running lean, the opposite was the case. It was drowning!

These engines don’t like to draw on disturbed air – that’s one of the reasons the intake snorkel faces backwards. The airbox itself is also designed to provide consistent, controlled airflow, critical to getting a big V-twin to run sweetly. And bear in mind more intake noise – or any noise for that matter – doesn’t necessarily equate to more power…

Do not remove the airbox on your KTM. It'll make more noise, but will drink fuel and run poorly.

Do not remove the airbox on your KTM. It’ll make more noise, but will drink fuel and run poorly. Think of it as your engine’s lung…