??? About Thermostats in Race Bikes. Remove? yay or nay?

The differences in temperature are part of the issue with why the flowrates are important in the radiator and not as much of a concern inside the engine. The engine is producing much higher temperatures internally so the delta Temp between the engine cooling jacket wall internally and the coolant flowing outside of it is much higher than the delta T between the coolant and ambient air outside the radiator. The fluid doesn't have to be in the engine jackets as long to transfer enough heat(rates for given delta T no different). Basically, the efficiency hasn't changed but this rate isn't as important inside the engine as it is the the radiator.

As Kenny mentioned it is a balancing act that engineers have to consider. You get into laminar flow on the heat transfer surfaces, system pressures, coolant used, etc. The system is pressurized to prevent rapid boiling in the engine but allow the engine to still operate above 200-220. If boiling occurs then heat tranfer goes away. The onset of boiling, nucleate boiling is actually the ideal heat transfer condition. It's when the tiny bubble are forming and moving away from the surface. Departure-from-nucleate boiling is bad. That's when the bubble get larger and move away too fast and doesn't remove heat efficiently.

 

Is 3,200 miles to early for a t-stat to fail on a 2008 bike?
Ordered T-stat replacement ($39) shiped to my door.
sorry for using ??? in my titles... not sure why I did that ???

 

If it were a Honda it would be. Only 2 ways to find out. Take the old one out and boil it and see if it opens or put a new one in and see if you can replicate the problem. I assume you did check the overflow and rad level to ensure that the system was full

 

yes , all checked...
I have most of the detail on page 1 and 2.
http://forums.13x.com/showthread.php?t=231145&page=2

 

Interested posts.

I've been dealing with an overheating problem with my 675 this season (new motor). Tried all sorts of things, but never found a complete solution. Water just boils over as I enter the pits, and fills up the overflow. The amount in the overflow is about 1/3 the amount loss in the radiator, so i'm guessing that it's vaporizing somewhere. Belly pan is generally dry, so no overflow there.

Did all the typical burping of air out the system, warmed it up without a cap, etc. Air seems to still be getting in, for the motor is MUCH hotter than the radiator. i'm looking at the head gasket as a strong possibility. Will probably replace the radiator and water pump just for good measure.

Richining up the mapping did have a positive effect, but it wasn't a total cure.

Bike never had a thermostat, but it also ran an entire season, prior to my ownership, without one. It was previously raced in Canada, if that matters

 

So your running pure water?

Are you still not running a stat?

Its possible you have a leaking head gasket.

 

"So your running pure water?

Are you still not running a stat?

Its possible you have a leaking head gasket. "



Water wetter and distilled water. I'm pretty sure the last team that owned it have removed the stat.

Yea, I'm thinking the head gasket. Can't see that much water vaporizing that fast. Feels like air is getting back in, never can burp the hoses enough to get the bubbles out.