We’ve done a few of these Grisos now, done our homework and have got a really good angle on what makes ‘em tick. Like any modern big twin they’re strangled to death with emission controls, and the effect of all the interference is magnified compared to a four cylinder.
And it’s slow speed running – in traffic for instance – where a V-twin’s problems are most obvious. There’s no consistency; they splutter, cough and (short of fuel) are just plain horrible to deal with. So our first job is to switch off all the equipment that’s messing up the engine, and then we can address the fuelling and give the engine what it really needs.
We also map each cylinder individually because they never run quite the same. The real truth here is that the standard map the bike comes with may well suit a percentage of bikes but won’t suit them all. So if you get a good Griso – and they’re out there – what that means is your engine is very close to the engine used to develop the stock map.
Unfortunately, the inverse is true, and a bad one is a real disaster. When we’ve remapped one of these the telling difference we find out on roadtest is that you’d be hard pushed to tell the difference between the injected engine and one fed by carbs. Nuff said!