KTM Duke 390 2017-18 Sump guard/Skid plate Modifications

In my last post I described the path to getting the great AS3 Performance sump guard/skid plate to fit on the newer models of the KTM Duke 390’s. It was a great success however after a few hundred miles I ran into an issue. It was noise.

The metal vibrations due to the sump guard sounded very odd. So I decided to fix this. After a quick test of concept with some simple rubber washers I decided to make some rubber spacers to damp the guard from the engine itself.

I took a sheet of 3mm rubber I had to hand and cut 4 small washers out, 2 larger round washers and finally a large section to cover the main bracket.

I then backed these with some high strength 3M double sided sticky tape.

Next I stuck the three larger washers onto the sump guard, on the inside.

I needed some 5mm longer bolts to attached the guard, as the stock ones were too short with the rubber sections in place. I probably could have eliminated the rubber washers for the bolts themselves, but I thought I may as well damp as much noise as possible.

The Results

I’m very happy with how it turned out, it fixed the problem completely. For a 30min investment in time and some materials I had laying around it was great. I made a quick video of the sound before and after to show the difference.