srad34 Posted July 28, 2014 Report Share Posted July 28, 2014 I have decided to fit a HRC overflow/expansion bottle on the ZXR to replace the huge one under the race seat. My question is do I need to fill it with any fluid before use? - May sound like a daft question but the coolant in the old bottle does not seem to increase or decrease when the bikes running. Thoughts chaps.... Link to comment Share on other sites More sharing options...
TLRS Posted July 28, 2014 Report Share Posted July 28, 2014 I would put something in. When the cooling system is free of air it should only expand towards the bottle. But when it's cooling down again you want to make sure there is level to draw coolant from. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted July 28, 2014 Report Share Posted July 28, 2014 Fit a 1.3 Bar cap on it. Fill to the brim and leave the expansion empty. The bike should sort out what it wants to do. Pressure test it by running static up to 105 degrees. If your hoses don't pop of 'cause you've got a weak jubllee somewhere, you should find that the cap doesn't lift and the system is sound with nothing in the bottle. The overflow will just be there if you happen to super-soak the engine on a very hot hay. If you're running without a fan and thermostat it's best to fire the bike up from time to time in pit-lane to get the pump moving and bring the internal temp down slowly as the rad will cool, but the oil and engine won't as fast. Link to comment Share on other sites More sharing options...
lorenzo Posted July 28, 2014 Report Share Posted July 28, 2014 Where would one find a 1.3 bar cap, for a suzuki perhaps? Would a 1.6 one cause any damage? Edit: Think I've found a 1.3 one now, I'll get it ordered. Link to comment Share on other sites More sharing options...
srad34 Posted July 28, 2014 Author Report Share Posted July 28, 2014 Do I need to change rad caps as the oem system was not an issue? The Cooling system has fan and thermostat fitted as the bike gets used on road too so I will make sure the system is topped up and just put 150ml of fluid in to ease my paranoia. I am on track Friday so that will test it for sure! Cheers Link to comment Share on other sites More sharing options...
spacemonkey Posted July 28, 2014 Report Share Posted July 28, 2014 The cooling system is pressurised simply to keep the water from changing state to gas. It expands as it gets hot so a valve lets it out into the expansion tank. So you don't have to keep topping it up after every run there's another valve to let it back in when it cools. Hence while it is not strictly necessary to fill the bottle, it's a good idea so you can keep an eye out for leaks and keep the pipe bled. If there's too much water it'll just come out the oveflow. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted July 28, 2014 Report Share Posted July 28, 2014 Sorry, was busy trying to kill Lorenzo's stone in your thread Advice is still valid though, you'll end up with less water sloshing about with a 1.3 fitted. Good practice at the circuit even when you're not using Glycol. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted July 28, 2014 Report Share Posted July 28, 2014 Where would one find a 1.3 bar cap, for a suzuki perhaps? Would a 1.6 one cause any damage? Edit: Think I've found a 1.3 one now, I'll get it ordered. Don't fit a 1.6, if it gets that hot it'll blow the head gasket before the cap lifts. Link to comment Share on other sites More sharing options...
kanerdog1x1 Posted July 28, 2014 Report Share Posted July 28, 2014 Don't fit a 1.6, if it gets that hot it'll blow the head gasket before the cap lifts. this. just fill the rad to the absolute brim, run as normal, any water that doesnt want to be in there will soon find its way out of the cap. you have two choices with the overflow bottle. 1:- run it empty. this is fine but you will always find that if you open the cap then there could be an air gap(that disappears when the engine is hot) and potentially there is air in the system. 2:-run the bottle 1/3 to 1/2 with coolant, this way the air cannot get back in when the engine cools. same as bleeding brakes with a bottle. you dont need to run the bleed hose into a bottle with a bit of fluid, but its always easier to do so. Link to comment Share on other sites More sharing options...
Wildbill Posted July 29, 2014 Report Share Posted July 29, 2014 I run a couple of L models; one has the same set up as you; a HRC bottle just below the filler cap. It runs fine with the std cap and the level remains constant at 1/3 full. Link to comment Share on other sites More sharing options...
RonniB Posted July 29, 2014 Report Share Posted July 29, 2014 What about that evans waterless stuff, is it make-believe or good. Link to comment Share on other sites More sharing options...
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