Barry_MC21 wrote:Can I just ask, what the problem with the stock radiator?

Do people have problems with it overheating on the road, or even trackdays?

Yes and yes, I saw 101*c on mine round London for the Chelsea bridge ride out on a cold wet evening, I believe Bill said his heat seized at 104*c. I also saw it well up in the 80's at Donington and it wasn't even hot that day. The thermostat is to maintain the temperature where it should be not to keep it cooler, the point is the stock radiator isn't up to the task of keeping a 60+bhp bike cool either in town or under constant load in the heat, hence there is an F3 and an HRC radiator, the problem is the '28 one (if not the '21 one) requires the HRC airbox as well and the pair will set you back the best part of a grand.
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