I’ve had an il4 600 for a few years and have gotten used to the zero engine braking on the down shift.

It’ll lock the rear when I get the speed/timing wrong rather than slow the bike it seemed. Got used to it.

Riding a litre V twin now and was expecting the engine braking to be much better but though better it wasn’t what I expected.

I had the chance on a tdm 900 over last summer and it had decent engine braking. Was advised to drop a gear going into a corner to avoid loading the front with the brakes as it suited the bike. Seemed to work fine.

The new bike has a euro 4 exhaust and I got around to drilling out the baffles today.

Holy shit now it’ll nearly put me over the bars the engine braking is that strong. Not through the whole rev range though. Higher revs it’s less noticeable.

So to make a short story long.

Why is that? How can removing a couple of inches long pipes at the end of the exhaust make a dramatic change?

(I am liking the change. Noise and braking. Just curious)