UncleCranky

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

Thankyou Carlitos92, sometimes its the obvious things that are hardest to find on your own. Thermostat is only partially opening. New thermostat and radiator cap (just to be sure) ordered. I will reply when I've tested it. Thanks again - Cranky.

Hi all, I've seen a few posts on 5th and 6th Gen overheats, but haven't seen the "Eureka" solution. I've done some tests on my 2010 800, and I can't see which part of the cooling system is not functioning. My problem is on warm days (over 27 Celcius), if the engine temp reaches high 80s (C) it will quickly climb to 106, fan comes on, temp will not drop below 100, and steadily gets hotter whether idling or riding in traffic. (I've shut it down after 115, have a rest for 30 mins, before continuing). Highway speeds will hold it at around 104 to 100. Overflow level is fine, changed coolant (used both drain plugs), burped and check levels again, all OK. After the coolant change, testing in the garage, ambient temp is 27 Celcius: Start bike from dead cold (Engine temp "--") Hold revs at about 2000. Watch temp climb, thermostat opens at 80, both radiators have warm water flow. Temp drops to 76, then climbs steadily. Allow to idle, 1250 RPM. Temp continues to rise steadily to 106, fan comes on. (About 15 minutes from thermostat open) Temp drops to 96 (about 5 minutes), fan stops. Temp rises to 106, fan comes on, drops to 96 (about 10 minutes), fan stops. This cycle heating/fan/cooling cycle continues with the time it takes the temperature to drop extending until it just will not drop and climbs to 115+. This cycle is the same on the highway, or in traffic. "Normal" riding temp when it can control itself, is 86 deg C. Sorry about the long waffle, but I just really want an answer, I cant enjoy my ride when I'm constantly looking at the temperature gauge.