I would think if your thermostat was shot it would get hot rather than stay cool.

Personaly I think around 62deg is about right. Ive never had mine run that cold though but often have to use 2 strips of tape to bring it just into the 60's in winter.

It would seem though that Honda did have trouble keeping the NSR's cool though as, like you say they made the HRC rads as well as the HRC water pumps. To prove a point, the amount of heat that came off Matts 300 in Thailand would shame a VFR!
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If I have to take the carbs off once more...