I too was concerned about this when i first converted over to coolant heated C3 bars..... so i looked it up and this info is on their website...
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link:
Heated handlebars and thermostats go hand in hand. Thermostat keeps your engine warm and our coolant heated CenterFlow handlebars keep your hands warm.
c3powersports.com
then click on Bars FAQ tab.
Copied from their website:
I heard it's bad to dead-head the bike's water pump?
Where did you hear that???
4 things:
- A C3 thermostat + bars setup can never be deadheaded. Our thermostats are built to our custom specifications with a small bleed hole, so there is a built-in bypass system at all times.
- Even if you could, "dead-heading the pump" is not a swear word or even a bad thing at all. Ask anyone who's worked in industry - it's a very common and very widely used method to throttle centrifugal pump flow and control complex systems.
- The reason that you may have heard as a warning against deadheading pumps is if the same liquid is churned around in the same space for an extended period of time (typically hours and hours straight), the friction will eventually build up enough heat to straight-up vaporize the fluid ("cavitation"), and those pockets of gas are indeed bad for the impeller and bearings. There are some applications where this is a legitimate concern, but clearly that's not the case in a motorcycle engine scenario where any liquid friction heat is negligible (to say the least) compared to the internal combustion occurring in the cylinder inches away! And it is ESPECIALLY not a concern in a system where the thermostat itself inherently acts as a safety control valve, sending up to 100% of coolant flow through the radiators if the coolant temp gets even remotely close to boil point. So all good! At least when you're talking centrifugal pumps like on bikes ("positive displacement" type pumps, that's a different story)
- If for some reason you are still concerned, with the valve conveniently located directly ON THE HANDLEBARS with all your other controls, you will have no problem maintaining a perfect level of warmth on the fly without ever closing it entirely, if that is what you choose!
- If for some reason you are still scared or apprehensive, we will add the fittings for you to elegantly plumb in another bypass circuit to your next order for free.
What about "hot spots"?
See above about A) the optimized "bleed hole" ensuring the proper slow circulation (never stagnant), and B) the cylinder of course heats up all coolant uniformly - definitely don't worry about "hot spots" in C3 systems.
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anyhow, ill always leave the valve slightly open anyways.... ?