Johnny Blanket blues...

[Sebsi]

Tomorrow I leave Colorado for California, my first big trip on my 93 K1100RS I bought in May. I've put on over 4K miles in about 9 weeks. Because I am driving through serious desert heat on the way, I did two heat-related services on the bike yesterday: drained and changed the coolant, and installed a Johnny Blanket.

But first: I've had some problems with this bike, all related to heat. I had gas pissing out the fuel vapor line, I was stalling at idle in hot weather, etc. I've fixed all of these (air accumulator, re-routing the fuel return line in the tank, installed the fan switch mod, etc.) But it was still hot, and I wanted to be as prepared for Arizona and Utah as possible.

So yesterday I changed out the coolant first. The only hitch was I got the two sensor leads mixed when I replaced them, so when I turned on the key the water temp gauge shot all the way to the right, and the oil light was on. I immediately turned it off and put the sensors on the correct bolts. One is obviously the water temp sensor, but I don't know what the other one is. I rode it up to heat, adjusted the coolant (Prestone 40% water 60%) and it ran fine for an hour to up a friends, where we installed a Johnny Blanket. Temp readings were normal.

Today, on an hour's ride to work on the freeway, the bike was running at a lower temperature than normal, 'normal' being the temp gauge just the left of 12 o'clock. I'd call today's reading 11:30. When I got off the freeway for about 3 miles of stop and go, the temp went even lower, and I've never seen it that low. When I stopped, I noticed the fan was on, which happens routinely when the gauge is just about to red. So that was weird. Even stranger was the fact that the tank was hot. Really hot. But it wasn't even 80 degrees out. So to sum it up, the bike ran fine pre JB, but post JB I feel like I've got a hotter bike but my temp gauge reads the opposite.

So, any thoughts on this? It sure seems like either the sensor mix up fried my gauge (although it worked fine yesterday) or the JB is somehow cooking my tank instead of cooling it, but at the same time cooling the motor? What causes the fan to come on? I know, it's heat, but where is it measured? How do I test whether my water temp gauge is working correctly?

Again, I'm off on a trip tomorrow through some hot locations, and I need to depend on my gauges in a big way. I'll probably remove the JB for the hour's ride home to see if that's causing it...maybe I'm shorting something out...

Anyway, sorry for the novel, and thanks for any help here.

Seb

[Grim]

I hate to say it but I'd be more inclined to think the gauge or possibly the sender were damaged.

I have the JB and very happy with it.  The tank will still pick up heat off the fuel rail and lines not to mention just being pressurized by the pump but it retains no where near as much heat as what it was getting before I installed the JB on my bike.
 I actually got 1st degree burns on the inside of my thighs though a pair of pants when I got caught in traffic once.

[johnny]

did you squeeze the bottom hose while slowly adding coolant... did you burp it by taking it to fan on then topping it off after it cools... how much coolant did you getts in there...

id put it on the center stand and start it up and let it idle... note where on the temp gauge the fan kicks on and shuts off... then when cool slowly squeeze and top off...

j o

[Sebsi]

I'll test the coolant and fan tonight. Very strange to have the fan come on with the temp gauge so low, so that certainly suggests that my sensor's hosed but the fan sensor (which I believe is on the radiator?) is working.

Thanks fellows.

Seb

[Sebsi]

I neglected to mention that when I was screwing the drain plug/temp sensor back in I felt a very slight "give" after tightening it. I am guessing I twisted it off a bit, just like this:

http://www.k11og.org/forum/viewtopic.php?t=4937&highlight=water+temp

That's an expensive little part, too....

Seb

[Sebsi]

OK, just took a break from work and here's what I found out:

The fan comes on when the temp needle's not even out of the blue. So my sensor is hosed. I either ruined it by overtightening it or by hooking up the wrong lead to it. So no water temp sensor across the desert...

Seb

[johnny]

you could have one fedex tomorrow waiting for you at your tomorrows destination...

j o

[wmax351]

Those are Negative Temperature Coefficient (NTC) sensors. Excess resistance reads cold. If you put the oil pressure switch lead on the sensor, it would give a full 12 volts through the sensor, and can burn up the sensor element. The temperature sensor line has a "Bias Resistor" that allows the analogue or digital circuit to compare resistances.


I wouldn't worry too much about temperature. These engines run hot, and as long as the fan turns, you won't have an issue. If you do, the light turns on. Only time that's happened to me was cruising at nearly 100, on a 100 degree day, in Nebraska, when I had it WFO, with the fan fuse blown.




I've considered plumbing in an old oil cooler from some motorcycle to act as a heat exchanger/fuel cooler. Even on my naked K75, I had the fuel basically boiling on a hot day.

[Sebsi]

Well, made it to Moab from Denver. Bike performed admirably. Fan came on when it usually does.

Johnny, PM sent.



Seb

[Sebsi]

Update:

Replaced the water temp sensor/drain plug and I've now got my water gauge back. According to the gauge, the bike runs a bit cooler and the fan comes on earlier than usual (it used to come on when the needle just about hit red; now it's about half way between the hash mark and red), which I doubt is the case and assume than there is some variance between units and the bike's running the same as it was with the old unit. I did change coolant and am now running Prestone Extended Life, but I don't think that would cause the bike to run any cooler...so my guess is that the sender in the radiator is running "normal" and the water/drain sensor is running "cool."

Anyways, thanks again for the help.

Seb