I've now managed to obtain the standard screen from the guy I bought the bike from.
I removed the Ermax touring screen and rode up to collect the other one.
Riding without a screen:
- A feeling of 'space'/good visibility/smaller bike -It felt as if I was riding a big supermoto like a Hypermotard
- No buffeting and only a bit of wind-noise from the helmet. I could hear the engine at motorway speeds.
- At an indicated ton on a private road, I was having to hang on hard. It was basically like riding a naked bike (how quickly you forget what it's like!)
I fitted the standard screen and rode back.
- less buffeting than with the Ermax, but more than without a screen
- Sitting up a little lifted my head out of the turbulence.
- Similar wind protection to the Ermax screen.
I'm tempted to cut down( like Graeme's) the Ermax as I don't think it offers any advantage over the standard screen.
Cutting out a slot across the bottom and fitting a plastic sheet
á la Geordie Guy could be the way forward.
Has anybody else got pictures of their cut-down Mk2 screens for ideas?
ps. I must be getting soft, but If I come into money and get a big capacity muscle/street bike it'll need a bikini fairing at least

Took my screen off yesterday and went for a ride too - definitely removes the noise/buffeting, but it puts a fair amount of pressure on the upper body, that would get tiring after a while.
I emulated Geordie Guy's mod by putting strips of duct tape (credit to Azza for that idea!) across the fairing behind the screen, then lifted the front of the screen by screwing the bottom 3 screws into the fairing (leaving them sitting up slightly), then sitting the screen on top of the screw heads and putting the other 4 screws in as normal to secure the screen. This left a gap the width of the screen and about 8-10mm deep along the bottom edge of the screen.
This noticeably reduced the buffeting and noise, however the noise is still significant at highway speeds. A rigid insert rather than just duct tape would be better I think (the duct tape vibrated in the wind channeled up under the screen, which would have created it's own noise), as would a larger aperture in the screen. I will duct tape a sheet of rigid plastic in it's place, and lift the screen a little more, then see how that goes.
While riding around experimenting I noticed that most of the noise is coming up into my helmet from my neck area - if I put my hand across the base of my helmet to block the wind it removed most of the noise. I will try to get hold of a helmet Windjammer or similar before this weekends ride, as I think that may make enough of a difference to make it comfortable touring. (hmm... duct tape??

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I suspect the cut down screen as Graeme has done might be the way to go for a proper fix... just need to get used to the appearance...