A story within a story here; most of these 2016 Euro-4 spec bikes like this BMW tend to carry a huge canister of an exhaust tucked underneath. This allows the manufacturer an awful lot of scope for siting catalytic converters, crucially though without a lot of restrictions.
And here’s the point – we fitted a full Arrow system (with the 5p baffle in the back of it…) and its performance was worse than standard. This happens regularly and the truth is that these aftermarket exhausts are not designed to run with a baffle. So it had to go (which the owner wasn’t happy about) to get at the power. There was a gain to be had, but not a massive one and obviously there’s a weight saving but you’re left with a horrible, noisy bike.
We contacted Arrow UK to be told that the exhaust we’d fitted was the first one they’d sold… we were guinea pigs. They got in touch with Arrow in Italy who re-manufactured the baffle and sent it direct to the owner; the bike is now quieter and running sweetly.