hey guys,

I did some research on the temp sensors and found out that my k100lt '89 has a sensor with a different part number than the sensor placed in k1100lt up till '93 even though they look the same.

the real oem tells me that my part number is 61311459197 for $82 whereas the k1100 has 13622242184 for $37.

the second one can be easily substituted with a car sensor for $10 as the same sensor was placed in multiple cars such as lancia, alfa romeo etc.

is there any difference between those two?

cheers!
Pajonk

ok, found a FAE one for my bike for $12! over 3 times cheaper than on motobins. the original BOSCH one costs $30. if anyone needs one, i can get you one here in poland!

cheers and sorry for the post

pajonk wrote:is there any difference between those two?

The one for K100 (Jetronic, analog) is a dual element (1. ECU, 2. fan management), other end of elements connected to ground via coolant stub. Measuring temp. by the difference in resistance to ground.

The one used on K1100 (Motronic, digital) is a single element and not connected to ground.
Both ends of element connected to motronic, measuring the temp. by drop in voltage.

Inge K.

certainly would not be helpfull paj......

thanks Inge! and yeah Charlie, seems like it would be a bad idea to use the k1100 one;)

but as i said, i found the k100 sensor for $12 so i am satisfied.

cheers!

cool what a win paj....good work buddie !!!

Inge, any idea on the differences between the early and late K1100 sensors.  The early is the solid one with the green plug and the late one has a short lead with the connector on the end.

What would happen for instance if I were to fit the earlier version to a later engine and Motronic 2.2?  I've done this and the bike is using much more fuel than previously although its idling better than it ever has.

Al

No, I've never compared them side by side.
But from your experience it seems like the later one have a bit higher resistance.

Inge K. wrote:

pajonk wrote:is there any difference between those two?

The one for K100 (Jetronic, analog) is a dual element (1. ECU, 2. fan management), other end of elements connected to ground via coolant stub. Measuring temp. by the difference in resistance to ground.

The one used on K1100 (Motronic, digital) is a single element and not connected to ground.
Both ends of element connected to motronic, measuring the temp. by drop in voltage.

Inge K.

Hello Inge, pajonk

I measured resistance between my #10 pin (K100 Jetronic) & ground. It is strange, I measure 1.8K momentarily and then the meter shows open circuit. If I lift the prong of my meter, break contact, and then return to contact #10 it again shows 1.8K, but again only momentarily.

It puzzled me. I have another K100. So I repeated the test on that one. The same result, 1.7K momentarily and then open circuit.

I thought, maybe my meter is faulty. So I checked the resistance of the air temperature sensor - resistance between pin #8 & #9 and it's a steady reading.

I unplugged the fuel tank electrics to make sure #9 is not connected to ground via that connection.

Does anyone have an explanation?

AL-58 wrote:Inge, any idea on the differences between the early and late K1100 sensors.  The early is the solid one with the green plug and the late one has a short lead with the connector on the end.

What would happen for instance if I were to fit the earlier version to a later engine and Motronic 2.2?  I've done this and the bike is using much more fuel than previously although its idling better than it ever has.

Al

I should have got back with the result to my problem here. 

I changed the water riser(the sensor thread is different) and sensor back to the later version the motor originally came with.  The fuel economy is now back to what it was previously (between 14-16km/l).  I never measured the sensors to identify the difference but it's all good now.

Al

would be interesting to find out the difference al
I have a feeling that the sensor that fixed the issue will have a different  lower "hot" temperature reading

Kafflut wrote:
I measured resistance between my #10 pin (K100 Jetronic) & ground. It is strange, I measure 1.8K momentarily and then the meter shows open circuit. If I lift the prong of my meter, break contact, and then return to contact #10 it again shows 1.8K, but again only momentarily.

It puzzled me. I have another K100. So I repeated the test on that one. The same result, 1.7K momentarily and then open circuit.

I thought, maybe my meter is faulty. So I checked the resistance of the air temperature sensor - resistance between pin #8 & #9 and it's a steady reading.

I unplugged the fuel tank electrics to make sure #9 is not connected to ground via that connection.

Does anyone have an explanation?

That would normally indicate corrosion between the sensor thread and engine block, but if the other K100 is doing the same it might indicate something else entirely.... OR.... they both have a corrosion problen????

I would be removing the sensor, cleaning it and then check the measurement again. It is also possible the copper washer is badly oxidized and acting like a diode. Charlie had one some years ago that was acting very strangely until cleaned up.

It becomes even more confusing. I felt pretty certain that as Rick G and Holister suggested, there is bad contact between the sensor and frame. I removed the sensor from the bike that had no coolant, the "other" one - easiest to do.

The surfaces of the washer were bright shiny Al. Nevertheless I cleaned it thoroughly and sprayed CRC. I measured resistance between contact point 1 & the brass body of the sensor - 1.8K momentarily. I measured the resistance between contact 2 and the brass body of the sensor - 1.8K momentarily.

There's more.

I went back to working on the first bike, the one with coolant. I started it and ran the engine for a minute or two.

I thought, let me check the coolant sensor resistance now. Would you believe 1.1K steady reading!

What battery is in the meter you are using, it may be that a higher voltage is needed to get a correct reading at low temperatures.

Meter has a 9v battery. I tested the battery - it was okay. I'll replace and post what happens.