What is Hot?

This was in traffic this summer.

 

overheating concerns

Hey Guys, I am new to VFR world, but not to motorcycling. I currently have an 06 zx-10r Ninja, that has a tendency to run at elevated temperatures.If all goes according to plan I should have a 99 vfr shortly. Anyway back to cooling issues, no one mentioned if they were running an aftermarket exhaust system. When an aftermarket exhaust system is installed it will make the engine run considerably leaner, leaner fuel mixtures are hotter fuel mixtures.
In order to compensate for this you need a powercommander or a modification
to your ecu that richens the fuel mixture. In addition the use of premium fuel will make an engine run cooler. Also the ratio of coolent to water should be changed, try 60% water and 40% coolent that should help coolant efficiency. This is not just BS guys, it has been learned over a number of years and from some very big time racers. Thanks eddie cap:smile:

 

SO, here is what I want to know. Has anyone driven their VFR to seizure caused by overheating? If so, what was the temp. when it siezed? That's the temp. I'll stay away from! eddie cap.... 60/40 W/C or 60/40 C/W... Seems like the way you put that it should be the other way around. Water conducts better than ethylene glycol?

 

I agree, 250 F is too hot, and at that point I pull over and let it have a rest. The fan does come on at the proper temperatures. I have installed a voltage monitor, so I can watch exactly when the fan comes on and goes off relative to the engine temperature. It is working exactly as it is supposed to. I also pulled and checked the thermostat. (not for the faint of heart btw). I tested it to specs with a pot of heating water. It opened and closed exactly the specified amount at exactly the right temperatures. I have also pulled and inspected my radiators for obstructions or other problems. Again, no issues. I have flushed and cleaned my radiators with white vinegar. I use only distilled water in my coolant mixture anyway, so there is no mineral buildup.

Danimal, your bike is a 6th gen, which has larger radiators and a fan reversing relay. At higher speeds the fan reverses to work with the speed induced airflow. The 5th generation does not and the fan always works against the airflow from forward travel. Despite all that VTEC gimmickry and extra weight, the 6th gen bikes do have some improvements over the 5th gen bikes ;-)

The 2000 and 2001, with the cat and the smaller diameter exhaust pipes run the hottest of any VFR's. My friends 99, under identical riding conditions gets hot but not as hot as the cat equipped bikes. I sometimes swear at the cat and call it a sump heater.

When I say I have tried everything, I mean I have tried everything. Different coolant mixtures (including water wetter, higher percentages of water over ethylene glycol, propolyene glycol coolants) different oil weights, even reversing the fan direction by rewiring it. No dice. This thing just runs hot.

A common practice in Europe is to install a switch on the fan to turn it on manually. This way when you reach a stoplight you can switch the fan on early, before the thermostatic relay kicks in and you get "stuck on the fan."

Earlier generation bikes, with their properly placed radiators do not have these issues. 6th gen bikes have the problem mostly resolved with the larger radiators and fan reversing relays. The later 5th generation bikes, which otherwise would be the most perfect VFR of all, are spoiled by the heat issue.

 

Would a larger oil cooler help keep temps down?

 

On the old VFR list there was talk of swapping the oil cooler out for one from the superhawk. I would want to install and gather some data from an oil temperature gauge before I made the swap. Oil and water temperatures are different things. I'm pretty sure my oil is getting very hot (hence I run RedLine oil only) because the bike gets to a condition I think of as "heat soaked." Even when I get to clear roads and can run at speed (85+) it still takes a long time for the temp to come down. But one of my next steps is to quantify how hot it is actually getting. If the oil isn't all that hot then I'll forever stop worrying about it. My fear is that the "sump heater" cat is cooking my oil to temps at least as hot as the coolant.

The reason I'm cautious about increasing the oil cooling capacity is that the oil system doesn't have anything like a thermostat, and it might be possible to overcool the oil, leaving it too thick to flow properly. I'd rather solve the problem with the cooling system.

 

Could a larger oil cooler really cool the oil that much? I don't know anything about the flow rate of oil through the engine but I would think it cycles fast enough to always stay viscous enough to flow properly. Actually, that also makes me think. If you had a larger oil cooler wouldn't the flow rate decrease? That might not be a good thing for this engine, seeing that it already runs pretty darn hot. If not, couldn't you compensate with a lighter weight oil than the recommended 10w40? Did I get that right? Sorry, I'm pretty ignorant of some things having to do with motors, I'm really trying to learn as I go along though!

 

All 5th Gen VFRs run hot (do a search and you'll see what I mean) especially in stop-and go traffic on a really hot day. This is because the fan reverses direction around 10 MPH or so and this causes it to fight natural air flow to a certain extent if you hover around that speed.

140F is perfectly "normal" for a VFR, but if it's going beyond the 250 and tripping the flashing red bar, you probably have a problem. If changing the coolant or altering the coolant mixture doesn't fix the problem, you may need a new thermostat.

They are a royal BITCH to change (...did mine this winter) so if you're not comfortable tearing into your bike, you might be happier just paying a shop to do it...


HTH,
Jake