2012 1199S--weird coolant temp display anomaly--

Hello all,
Went for a ride this afternoon on the 1199S-here in Austin TX it's nice and cool. It was about 60 degrees as I rode from 4-5pm.

In the slow sections, where I'm between 30-50 mph, my temp gauge would rise normally to high 190s-200 degrees. Then, with no warning, it would erratically climb to 220-230-240-245--then ease back down to high 190s. It would cover about a 40-50 degree range quickly, maybe 3-5 seconds. This weird sudden climb and descent happened about 4 times during a slow portion of my ride today.

Of course it's normal for the engine coolant temp to rise during slow bits. But not to 245 degrees!

I first noticed it when I had the flashing dash warning indicating the condition. (bright yellow graphic I think!) This caused me to look down for a possible loss of coolant, my first thought. But--no---the bike is water-tight!

Once I picked up speed above 65 mph--up to 85 today---the temps reduced as normal to about 185.

So--I suspect a bad coolant temp sensor.

Anybody ever heard of these going bad? If so, can somebody direct me to a part number link/repair procedure?

The engine felt fine and normal---super quick with the full race exhaust and map!

By the way, I recently wrapped up a front-end refresh on this bike, new heavier fork springs, new fork oil, and new seals/caps. WOW the bike's front end feels SO much better now--!

Greg

Glad you got your forks sorted out.

If it is the coolant temp sensor, it's in the thermostat housing in the V of the engine. Part 22 in the diagram, p/n 55242631A. It will probably require you to remove the tank and airbox. None of that is hard to do, just time consuming. I'd check my coolant level first and make sure I didn't have any air in the system.

Thank you bp- I’ve had the tank/airbox off before, I can do it again. I’ll check coolant level-shouldn’t be any air pockets but I’ll check. Would a bad coolant sensor throw a code-? No dash CEL evident-

I think it would if it didn't have any output, or the output was well outside of expected values.

Thanks, I just think it’s weird how the coolant temperature display read out was very quickly increasing and then decreasing, it can’t reflect a true coolant temperature change in that short of time span. How can the coolant increase by 45* in less than 5 seconds, then decrease again in the same time span?

I have to believe it’s a faulty sensor.

This rapid change in temperature readout only occurred at elevated temperatures, while riding at a lower speed. When the bike was moving rapidly, with cool air rushing into the front of the bike, the temperature readout was stable at a normal temperature. So I think the sensor is malfunctioning when temps rise a bit.

A bad ground can effect electronic sensors too. I haven't poured myself over the 1199 wiring diagram and service manual to know where all the ground points are, but it's something to consider.

greggiacona said:

Thanks, I just think it’s weird how the coolant temperature display read out was very quickly increasing and then decreasing, it can’t reflect a true coolant temperature change in that short of time span. How can the coolant increase by 45* in less than 5 seconds, then decrease again in the same time span?

I have to believe it’s a faulty sensor.

This rapid change in temperature readout only occurred at elevated temperatures, while riding at a lower speed. When the bike was moving rapidly, with cool air rushing into the front of the bike, the temperature readout was stable at a normal temperature. So I think the sensor is malfunctioning when temps rise a bit.

Click to expand...

Did the display ever do this?



Do the fans kick on?

Since you had the tank off recently maybe the temp sensor connector got dislodged. While you’re in there you could check continuity of the sensor.

2 other culprits could be thermostat getting stuck closed or water pump

1199 service manual
https://www.dropbox.com/sh/y4qam6tao88m7ay/AAB-BUjD_C3EWP0K1k_Nco5Ea?dl=0

SD--I never saw dashes. I guess that's telling. Not sure if the fans kicked on--couldn't hear during the ride. The super-high temps didn't remain for long--they dropped back down rather rapidly.

I had the tank off a long time ago--for another job-with subsequent non-event rides in-between that and this case. I do think it may be a sensor connector issue--recentyl as I was servicing the forks, I had the clip-ons off the forks, and bungeed to a resting point. Perhaps those cable bundles got stretched, (on either side) and maybe those clip-on cable bundles contain the temp sensor wire (even though they are tie-wrapped tightly)?

Thermostat/water pump--? Possibly. BUT----seems those items wouldn't explain my described symptoms as listed above: rapidly rising/falling temp values on the display, ONLY when at elevated temps. Temps appeared normal at higher speeds--but that could be explained by ram air effect. Still--the temp display behaved normally with bike at speeds above 60 mph.

The big question seems to be---why the strange temp display behavior ONLY when the bike is slowing and creating a bit more heat in the engine? Why didn't it act strange at ALL times?

I'll have to tear into it when I have time. I welcome any and all feedback--thanks guys!

Greg