Hey guys, does anyone know what the correct running temp of the 2010 klx250s is? Also what would be the max temp? Cheers

 

The factory thermostat starts to open around 160 degrees F and is supposed to be fully open at about 185 degrees F. The digital readout on my Trail Tech Vapor instrument panel seems to back that up. These are the temps that Kawasaki has designed into the thermostat, so that indicates that those temps are the intended operating temp for the engine. Now, max temp is a little different animal. The bike can operate for short periods at max temps as long as the coolant isn't heated to the point of complete boilover. We have a catch tank that extends those conditions of max temp, but it's only an extension. Constantly running the bike at max temps just short of complete boilover isn't that great for the long term wear and tear on the engine, but it will do it. So, what is that max temp? Boilover will depend on altitude and the conditions in which the bike is running...as well as cooling system integrity from something as simple as rad cap condition.

All that said, the KLX isn't a "hot running" engine by design and function. It seems to have a very effective cooling system. I've seen as high as 220 for a couple of minutes, and that temp didn't even push an coolant past the cap and into the catch tank. This occurred during a very, very long run down a dry, sandy, river bed in which the bike was constantly having to slog up and down the rpm range to keep on top of the deep sand. Since I installed a manual override switch on the handlebar to turn the fan on, I can flip the switch on whenever temps start to climb. The real advantage of a manual switch is the ability to stabilize or bring down temps before a huge amount of "heat soaking" builds up...usually at the 200 degree point or so.

 

Thanks for that. Just wanted to know as I have just fitted up a vapour too. Thanks again.

 

this is a VERY smart and useful mod, and one i usually add to any WC bike. i use a 2 position switch- with OFF being the OEM auto temp controlled function, and ON being "give me fan NOW", until i set you back to AUTO.

i have 2 honda VFRs. the older bike has an analog gauge, and the newer bike is of course digital.

the analog bike runs to approx 1/2 swing on the gage range, and pretty much stays there unless i get stuck not moving- and i hardly even give it a 2nd thought.

i watch the digi bike like a hawk, and constantly fret over the temps like nervous nellie.

i think about the design of temp gage on every cage ive ever owned. i think they are designed to stay mid-range unless really overheated. less REAL info keeps me dumb and happy in that case

 

I don't concern myself with the coolant temperature on my 2006. I have a Thermo-Bob which keeps the temperature stable and constant, probably around 185°. It gets plenty warm here in the desert, 115° isn't uncommon. The fan comes on as necessary, but the bike never overheats.

I think If it was important for me to have the fan come on at a lower temperature (if I didn't have the Thermo-Bob), I would just put in a lower temperature fan switch rather than have to deal with a manual switch. But, I'm lazy that way.

Ron

 

Please correct me if I'm wrong, Ron, but doesn't the Thermo-Bob help bring the motor up to running temperature sooner and set a minimum running temperature, but does little to nothing for operations above the minimum. If the thermostat is fully open, the Thermo-Bob does nothing to help cool the bike.

BTW, I have a Thermo-Bob and am happy with it. I like seeing the running temperature jump right up within a mile or two of riding, even on a chilly day.

 

You're correct. Ron just has all his retirements funds invested in thermobob.com, so he has to plug the brand.

 

I guess I wasn't clear.

The point I was trying to make was that even with the Thermo-Bob and its associated higher cooling system operating temperature, it isn't necessary (on my bike, anyway) to have the fan come on at a lower than designed temperature which is about 208°.

Ron

 

That's exactly why I can't retire!

BTW, I bought a new KLR (my third one) about a year ago. I bought a Thermo-Bob for it even before I took delivery of the new scoot.
It bummed me out that I had to ride it home (50 miles) from the dealer without the benefit of the Thermo-Bob. It went in the next day.

Ron

 

I picked up the Thermobob because of the bypass and the more consistent and uniform temperature level. There has to be a certain amount of heat, otherwise the engine will not function properly. Proof is the fact that the fuel mix needs to be richer when cold. Richer means less efficient in this case.

I know the Thermobob manages the water flow and thus the temperature up to the point where the thermostat opens. The bypass allows some thermosiphon effect and flow while the thermostat is closed. I'm thinking most cars and possibly bigger liquid cooled bikes have some kind of bypass allowing some circulation when the thermostat is closed.

In a side note, I used to experience severe overcooling on my MB5 Honda air cooled 50cc two strokes. They'd get so cold when running in freezing weather I'd have to pull the choke **** back out. I actually made a sheet metal shroud that fastened around the cylinder for winter riding. It blocked nearly all air flow from the cylinder. An engine can run too cold.