Vapor install is going great. Quick question. What is "normal" operating temp. What temps should I be setting my warning lights for? What temps did the factory warning light and fan come on? Factory displacement. Muzzy full exhaust. Rejetted.

 

Most four strokes run between 170-220 degrees based on Rotax, but I think the lower range should be more like 180 to 195 degrees. Pretty much just like cars.

I do remember Kawasaki didn't have any problems with their old Ninja 600s running upward of 240-260 degrees at one time. They had the gauge reading high on some bikes. The fix was to add a resistor to drop the reading, no change to the actual cooling system.

 

I like my yellow light to come on at 200 and the red to come on at 210. I also have a manual override fan switch. I like to use the fan if the yellow light stays on for a bit. It takes a very short time for the fan to quickly bring the temp back down. The cooling system on the KLX is very good.

 

Thanks for the replies guys. Very helpful. I'll post pics of my install Monday night. Very happy with my trail tech so far. FWIW I installed the thermistor in the crossover hose as that was the only hose that the sensor cable was long enough to reach. Hard idling to warm the bike all the way up I hit 188F. Cruising at 35-4" it stayed in the 110-120 range. Gonna be very Interesting to see what kinda temps it runs in Louisiana summer.

 

I would try to install the sensor in the hose that runs from the head to the radiator. That would give you an accurate indication of engine temp.

 

Here is what you need to do:

Put the thermostat from the bike into water with a candy thermometer. Heat the water and see what temp the thermostat will open...

Or better yet, before doing that, look at the thermostat to see if the opening temp is stamped on it or look in the manual to see what temp thermostat it should be.

I don't know where the temp is taken, but I'm thinking 110-120 is too cold. There has to be some heat there. If not the fuel mix will start to screw up. 100-120 degrees is hot to the touch, but not hot enough to hurt. I'm betting you can't grab the radiator and keep a hold of it when it is at operating temps. That and at that low of temps it wouldn't be a big deal to pull the radiator cap. 100-120 degree liquid won't burn you. Heck it won't even make good coffee! You better check what is going on there.

 

He said he put the thermistor in the crossover hose. That is between the two radiators. By the time the coolant gets there it is halfway back to cold again so I doubt that his thermostat is bad or that he has a temp problem. What he has is a useless temperature reading.

The 2009+ bikes have a goofy hose from the head to the radiator that almost doesn't allow you to use the thermistor there. If you do, it is a hokey install. This is why I skipped it until they come out with a radiator plug thermistor that fits our radiator.

The vapor has other stuff to watch.

 

Agree this is a useless, or nearly useless location for a temperature reading.
I found a brass radiator plug adapter unit at a local parts warehouse and pulled the dummy light sensor to install the Vapor thermistor & adapter combination in the left radiator. Seems like a decent location.

 

Well... I figured the water temperature would be about the same (or relatively so) anywhere in the system. After long, hard idle, I got the the thermostat to open, so I know my coolant system is working normal. I got a reading in the 180s after long idle. The cable on the sensor wouldn't reach to the hose down low.

I only got to do a short ~4 mile ride around the neighborhood after we finished our install so I'll have to hold off further judgement about temp readings until I've had more saddle time.

 

Comment On Max Temp settings on Trail Tech Vapor and Factory Fan Operation

There are a lot of posts on this topic so I chose to add info to this one since it directly addressed those using the Vapor.

Location of Temp Sensor - I installed a Vapor, placing the engine temp sensor in the thermostat-to-left radiator hose. As stated by another poster, you must be careful to cut out enough hose out for the sensor to not kink the hose and impeded coolant flow. The sensor wire was just the right length to reach the Vapor, which I mounted right on top of the bars at the triple clamp. I have Fatbars that use the adapter that raises the bars an additional 3/4". I am not sure if the cable length varies via application but I purchased the Vapor model# 752-300 for the KLX250S. I know there is a different part number kit recommended for KLX300 installations but I think the difference is the magnet kit for the speedo. Anyway, I believe this location will have the hottest coolant and best represent the temp of the motor.

Reason for this Post - There are many posts about max temp or safe temp that raised concerns about how high is too high, and where the fan should kick in if working properly.
Here is what I have to offer: When riding (easy riding on the street - breaking in a new 331), temps never went much over 160 degrees, often in the 150s (I should mention that I am in 'Merica where we use F, for degrees). After the ride, when adjusting the pilot screw and idle speed, I was surprised to see the yellow temp light come on (I had set at 205F) and cautiously watched the Vapor's temp display climb to over 215F before I shut the engine off.
The factory manual says the fan switch should kick the fan on between 203-214F. Here's the thing I learned when I finally let the bike run and let the cooling system do its thing - My Vapor temp was showing 220 (at the outlet of the cyl. head) before the temp AT THE FAN SWITCH in the lower tank of the right radiator reached 212 (based on the best non-contact IR temp gun that $20 will buy) and the fan kicked on.
Even sitting still the radiators are dissipating heat and had I focused only on the Vapor's temp display, I would have been worried that the engine was too hot and/or the fan switch was not working. The fan switch cycled the fan a couple times and I was content it was working properly. With this newfound confidence in the Kawi cooling system, I reset the Vapor first temp light to 225 (to tell me if the Kawi fan system has failed) and the Danger setting to 240.

I wanted to quote another poster who said he talked to Trail Tech for a temp recommendation, but I cannot find the post now (of course!). I BELIEVE he said they suggested 230 High and 257 Danger settings.

So don't expect the coolant temp to settle in a nice steady 190 or so like a car cooling system. In non-extreme riding environment or terrain, even with minimal airflow, the fan will rarely if ever run. Hope this is useful to someone!
TC