UncleCranky Posted March 29, 2020 Share Posted March 29, 2020 Hi all, ages ago I posted about my 2010 model VFR800Fi overheating in traffic. Thank you all for your help and suggestions at that time. I couldn't find anyone who was experiencing the same problem, so these are my findings, I hope it helps someone: Problem: The bike finds it hard to cool down on some days when the temperature is over 32deg C, especially when in traffic. The fan does its best, but eventually the heat/cool cycle gets away, and it cannot get under 110, then keeps climbing 118 is the highest I've allowed it to go. I replaced the coolant, thermostat, reverse flushed radiators, checked flow rates, nothing would keep it cool on really hot days. Then I found the problem. Humidity and the tropics. The drier the air the quicker it can cool the radiators. Its that simple. I now live in Brisbane Australia, bought the bike new in Cairns and it lived with me in Darwin for a while. These places are humid AF, always 80 to 98%. When I ride up into the mountains (Atherton, Toowoomba, Kyogle) - no problem. Back down at sea level in the tropics, one long idle session, and I have to manage the hell out of how I'm riding to keep her cool. So, I found the following helped heaps: 1. Kill the engine when stopped at the lights, this is the worst place for it getting over 105 in a hurry 2. Use low octane fuel on really hot days - this was amazingly obvious once I tried it 3. Ride as fast as possible in clean air. Lane Split, Filter, leapfrog, whatever, just get out in front of traffic and stay there. Thankfully, it's autumn here now, lower temps and lower humidty. Cheers - Cranks Link to comment Share on other sites More sharing options...
squirrelman Posted March 29, 2020 Share Posted March 29, 2020 always best to replace the rad cap b4 doing any other work as they often fail to hold pressure after many years. Link to comment Share on other sites More sharing options...
Member Contributer BusyLittleShop Posted March 30, 2020 Member Contributer Share Posted March 30, 2020 If you see *continuous* temps higher than 220ºF 104ºC or below 180ºF then trouble shooting is in order: Continuous engine temps above 220ºF or 104ºC is a problem and the proper order of items to trouble shoot are: 1)Faulty radiator cap... system should hold 1.1 pressure ratio... 2)Insufficient coolant... 3)Passages blocked in the radiator, hose or water jacket... 4)Air in the system... 5)Thermostat stuck closed... 6)Faulty temp meter or thermo sensor... 7)Faulty fan... 8)Faulty fan switch... Engine temps below 180ºF or 82ºC is an problem... it means that the moisture produced during combustion is not getting hot enough to evaporate out the pipe as steam... instead that moisture will migrate to the oil and produce a milky white contamination... Note normal by products of combustion is water... . Every gallon of gas creates roughly 8 pounds of water vapor... we all have witnessed water escaping out of tail pipes on cold mornings... The sequence of events to trouble shoot are: 1)Faulty temp meter... 2)Thermostat stuck open... 3)Faulty fan switch... (stuck on) Link to comment Share on other sites More sharing options...
Member Contributer boOZZIE Posted March 30, 2020 Member Contributer Share Posted March 30, 2020 If you have the black radiators check for blockages and flush thoroughly as they are painted on the inside and the paint flakes off. Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted March 30, 2020 Member Contributer Share Posted March 30, 2020 On 3/29/2020 at 4:17 PM, UncleCranky said: 2. Use low octane fuel on really hot days - this was amazingly obvious once I tried it That's an interesting statement, haven't heard of it before. Is there any solid evidence/reason to back this up? I only ever run 91oct anyway. Link to comment Share on other sites More sharing options...
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