OVER heating warning light

After a knee injury last weekend, I had to get to the ER which was 120 miles away. I could have waited for a ride or I could ride the WRR, 50 miles of gravel then 70 miles of interstate. I decided to ride the WRR. Turns out that I had a pretty strong tailwind and even with 13/48 in 6th gear, it would run 75mph easily. While on the interstate, the red warning light for "too hot" came on. I immediately stopped on the shoulder and checked the coolant, which was ok and after about 20 seconds the warning light went out. Things being what they were, I got going again, and had no red light for about 25 miles, then it came on again... so this time I slowed down to about 60 mph and after 20 seconds or so, it went out again. At this point, I was only 10 miles from the ER so I just held it at 60mph and made it ok.

Knee is not a fracture, but a really painful bruise... may need some surgery after the swelling subsides.

Anyway... is something wrong with the cooling system? Was I running the engine too hard? Was it all because of the tailwind? Maybe the water pump is going out?

What do you think?

Thanks, Gary

Did you notice if the fan was going at all during the stops? I know a few guys have switched out the stock fan with a stronger one. Not sure if that might be causing it, just thought I'd drop that in there.

I would guess that with a strong tail wind, there wasn't as much air flowing over the radiator, even if the fan were running.

The other thing to consider is that with "a pretty strong tailwind" you are not going to be getting much air through the radiator.

I'll never forget getting to the top of Manastash Ridge, WA, in the UniMoG, in August, with a tailwind, in 1st gear!!!! We had enough *power* to climb the hill, but with no airflow through the radiator the engine was threatening to overheat so we kept gearing down. FYI, top speed in THIRD in that truck is 24.07km/hr. I don't remember what it is in first, but I know you can see the individual tire lugs going by while the wheels are rotating.

Happy to hear the knee's not fractured, hope it heals up well.

Edit: phroenips beat me to it!

I'm thinking it might be a lean condition combined with high RPM. It's hard to accept insufficient airflow at freeway speed.

I had a similar incident last summer. It was 103° F ambient, about a 2% downhill grade at 70 MPH, maybe 80% throttle. My motor is all stock, so I think maybe it just runs lean in that condition, which I've heard can contribute to running hot.

I was almost at my turnoff and as soon as I slowed, the temp light went out and never came back, even though the ambient temperature increased throughout the day. That was the one and only incident.

I have a thermo gauge radiator cap, which is calibrated hot according to my meat thermometer in a pot of water comparison. Radiator fan works too.

The good news is - your temp warning light works !

phroenips wrote:

I would guess that with a strong tail wind, there wasn't as much air flowing over the radiator, even if the fan were running.

Come on. He's doing 70 MPH...Even if he had a 40 MPH tail wind there was still a 30 MPH breeze blowing over the front of that bike!!!

Do you still have the stock plastic shrouds on the back of the radiator? Removing those should cool things off.

Never had my temp light come on, long highway with a tail wind (a blessing imo) to tight single track abuse that had other bikes I was riding with puking and stalling.

overheating at highway speeds, id say its worth checking your tstat, temp sensor, and water pump.

Can get over 100 degree's here and I'v e never had my temp light come on riding hard on the Interstate.

I was riding in eastern Washington Saturday. I noticed my light came on for about 5 minutes, just after getting off the highway, and turning onto a dirt road. I have allready trimmed the fan shrouds, and added water wetter. I plan on getting a thermometer, just to watch things. I rode the bike 450 miles on Sat and Sun, and it never happened again.

I have been running in one of the hottest parts of the Mojave desert in and around Palm Springs, Lake Havasu, Lake Mead, and Lake Mojave. Starting in July (2013), I first noticed a over temp light come on and then had it come on at least 6 more times this month. It only comes on under moderate to heavy loads at high speeds 65+ and pretty much always on an uphill slope.  If I back out of the throttle and downshift, the warning light goes out in less than 15-20 seconds. The WR has not overheated to boiling over, just the warning light has come on. The outside temps are pretty much over 105 and can be +115F.  Probably hotter over the dark pavement.  When riding off highway in what would seem to be harsher conditions, no warning light.

I think I will try one of those temp gauge radiator caps so I could see the over temp condition coming on and adjust the ride rather than major adjustment when the light comes on.  I wish the light had a buzzer, so you for sure notice it.

17k miles, never ridden in July before (2012 bike). Engine, tuning, cooling and exhaust all stock.

Any ideas?