OK, hoping someone maybe able to point me in the right direction before I pull the whole thing apart. 1989 ZXR250A. Starts fine and runs fine. Revs freely. No leaks. However, it seems to get hot FAST. This is my 3rd zxr250. The other two never seem to warm up. The fans will only come on if I'm stuck in traffic on a hot day. But this one will get up to temperature and fan will come just stopping at lights on a normal day in Glasgow. Fan comes on just above halfway up the gauge, so that is fine. Fan cools engine a bit then switches off. Thirty seconds later it's back on again. So the bike isn't overheating, but seems to be getting hot too fast. Does that make sense? Coolant level is fine. Did a coolant change and old coolant looked good. No muck in it. Radiator cap is good. First thought was the thermostat might be siezed, but surely it wouldn't cool down with the fan if that was the case? Anyone had anything like this before?
I know nothing of ZXR's however overheating like you describe sounds like a water pump issue or the thermostat failing, because either one will yield diminished water flow You can let it get up to temp from a cold start at idle with the radiator cap off and check for proper water flow I've had thermostats fail, usually it happens in one go, they work and then they don't the symptoms sound curious
That was my thinking. Hoping it's not the waterpump. I have a new thermostat that I can fit (although my other zxr is needing my time too). Should have done it when I changed the coolant.
cheap enough part to replace http://www.ebay.com.au/itm/KAWASAKI...MP-REPAIR-KIT-X4-pcs-92049-0778-/191524101821 Check this post - perhaps you have a vapour lock http://2fiftycc.com/index.php?threads/where-s-the-second-air-bleeder-for-cooling-system.1399/
First thing to do is check all parts of the cooling system. Take the thermostat out and boil it. Does it open and close properly? If not, get a new one & temporarily run the bike with no thermostat (make sure you let it warm up) Take the water pump cover off and make sure the impeller is firmly fixed to the shaft and not loose, and that it hasn't corroded away into nothing. Backflush the radiator from bottom to top with a hose. Cylinder head should have some drain screws somewhere. Take them out and flush the head with the hose as well. You also want to start the bike with the radiator cap off. Do not do this after the engine has been running as the cooling system will be under a lot of pressure. Taking the cap off when hot = third degree burns. What you are looking for is bubbles. If you get bubbles then you have air getting into the cooling system somewhere (loose hose clamp etc) or a blown head gasket. If the head is blown you might get a sweet smelling exhaust, a big cloud of white smoke out the exhaust, or just gradual consumption of coolant. Have a look here for different types of blown head gaskets and their symptoms: http://www.agcoauto.com/content/news/p2_articleid/200 My FZR250R would also boil the coolant in the overflow tank after killing the engine and force it out the overflow tube. The engine and frame got too hot to touch unless you kept moving, and the radiator would constantly drain. I didn't get any white smoke clouds but the exhaust did smell sweet.
Changed the thermostat today. Takes much longer for fan to come on now. Old thermostat seemed to work (open at correct temp), maybe it was just tired. Sent from my HTC Desire 620 using Tapatalk
