That same old overheating problem!!!

[Phmode]

Good points all.

One other thing to consider is that the OE fan mount is solid to either side of the fan aperture.

This means restricted airflow when the fan is not running (i.e. most of the time) and I'm tempted to get my drill out and attack the flat portions between the reinforcing webs. If the air that does flow through the rad in the fan mount area has to 'spill' around the fan mount then that air is less effective than it would be with a holey mount.

[vm5]

That was my same thought about the dirt that easly close the radiator because of the fan screen that guide the air flow when the fan is running but stop everything when it's stopped.
Rather than drill the screen (compromise the air suction when the fan is running) it should be better to havethe same mobile flaps used on some cars.

[Sutty]

Good points all.
Brian
Last week at Aldi i bought a wood burning iron kit, not for any reason but just because it was only £10. Inside there was a Hot knife attachment and I thought I could slice down the side of the ribs to let more air through.

Rich, there is enough room I think, some of the fans on ebay look quite narrow, with the shroud gone it would be easier to back flush

Vm5, I did consider fitting solenoid controlled flaps to the existing shroud that shut when the fan was energised, but i think that would be a mission too far

Best regards   Mick

[Phmode]

One more consideration Mick. When I was thinking about changing the fan arrangement on my K12S, I thought of using stainless rod, 4mm dia. or so, to fabricate the fan mounting, much like the white frame outline in your mock up.

Easy enough to bend to shape and fashion the eyelets for the bolts, almost zero chance of stress cracks forming and almost zero wind resistance. It doesn't need to have the health and safety shroud cos no one in their right mind is going to go sticking their fingers in there...

And, we already have a precedent in the form of the radiator bottom mounting rod 

Of course, being a machinist that simple approach would be anathema to you 

[Andym535]

Why not put the fan behind the radiator and blow (forward) through the radiator? Counter intuitive, perhaps, but the fan only does anything when you're either not moving or moving very slowly. That might help blow some of the mud out of the radiator.

[Phmode]

Hmmm? Blowing the hot air from the engine into the radiator may not be the solution...

[Andym535]

I'm sure you could get round that with suitable ducting. VFRs had the radiators on the side, presumably engine heated air wasn't a problem there as I don't remember them having any overheating issues.

[vm5]

Vm5, I did consider fitting solenoid controlled flaps to the existing shroud that shut when the fan was energised, but i think that would be a mission too far

Best regards   Mick

But the flaps used in these way lift themselves as soon as the bike gain a little speed. Otherwise, when the fan starts and create depression, they're automatically closed.

[Sutty]

Yes thats an easier solution but the shape of the shroud would make it difficult.

Regards   Mick

[Costas]

Am afraid no matter how many ideas are going to be put in place the problem will always be the crud  and sand mixture used by road maintenance in your country during winder time , and (most unfortunately)  due to its design simply loves the rad of K bikes so much. The only way is to change the rad £550 if I remember correctly .