K11 Owners Group

[gpzoduibh]

Just wondering if anyone who replaced a bad air or water temp sensor could say how the engine ran before and after , I seem to have a prob where it runs really smooth when cold but when warm it feels "stuttery" and sort of like its running rich especially on 1/2 to full throttle ,
Regards
Bill Black
_________________
1995 Grinnall Scorpion III(1990 K100 16v motor)
2010 KTM 450 EXC
Moto Guzzi V50 powered hovercraft !
1989 K100RS (8V) special edition
1974 Yamaha DT360
1972 Sanglas 400 T
1980 Yamaha XS110-Watsonian Palma sidecar
1966 Bridgestone 175 dualtwin
1980 BMW R100RS
1979 Bultaco sherpa T 350
1979 Yamaha DT175MX
1990 Honda XR250R

[Scott_Anderson]

Well, not sure what your working with, year, type, etc...
Here are a coulple of posts from another forum regarding F.I. control and symptoms. Some of the info is duplicated but it should give you the idea.


snip.... The coolant temp sensor ( NTC II sensor ) increases pulse timing for a cold engine and this switch has about 40% authority. They age gradually and when they fail they can make the engine run stinking rich. A current is applied to the switch. As engine temp increases, internal resistance decreases, such that as temp rises an increasing voltage is sent to the terminal on the FI computer. In this way NTC II sensors fail rich, which is safe for the engine. If they failed lean, you could ruin the engine. I would be very suspicious of this switch and the wiring from it to the FI computer. You need to test both. A voltage leak in the wiring could fool the FI computer into thinking the engine was colder than it is. There is another NTC sensor measuring intake air temperature but it has a negligible effect on pulse timing.
One other thing to consider. Is it possible that a fuel line is routed so that it touches that radiator hose on the left side? I had this one baffle me once. I replaced the hoses and somehow was negligent enough to let the new fuel line lay against the radiator hose. When the bike was really hot the fuel in the line boiled and my bike died. I tore my hair out trying to figure this one out. Just an idea.

snip....The coolant temp sensor sends the FI computer a higher voltage as coolant temp rises. If the circuit has a voltage leak the FI computer will always receive a low voltage and interpret this as a cold engine, enrichening the mixture. Be sure the contacts and the master ground are nice and clean.
The other thing you mention is the outside air temperature being around 5 degrees C. That is fairly cold. If the thermostat is old and is sticking partially open, the engine coolant will never fully warm. The coolant temp sensor will always see a cold engine and the fuel injection will run a rich mixture. I just cured a rich condition on my own bike by replacing the coolant temp sensor and the thermostat. Example with my bike, one morning riding to the desert on a cold day my fuel mileage was only 28 mpg with steady 80mph running. After lunch it warmed up considerably and mileage imroved a full ten miles per gallon. When I removed the thermostat the next weekend it was observed open with a cold engine. Replacing the thermostat improved daily mileage several mpg. It's obscure but worth a look.
_________________
Ride safe.



1995 K1100LT 0302044
1997 R1100RT ZC62149
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)

[chopper_harris]

Try a 'plug-chop'

This age-old method will show you the state of the mixture from the colour and condition of the spark plugs.

Remove the spark plug cover plate.
Get the engine good and hot (In the UK this is a 20 mile ride )
While you are on the move (at about 3,000 rpm), switch off the engine and coast to a halt.

Remove the plugs one by one - check the colour and smell.
They should be a nice biscuit brown, with no noticeable smell of gasoline.

One dark or sooty plug points to a worn injector, all dark or sooty indicates bad fuelling.

HTH
_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

[gpzoduibh]

Thanks Scott and HTH?
The engine is a 1990 16valve K1 and its in the Grinnall scorpion a "plug chop" involves dropping the fuel tank ! Which is time consuming on the scorpion I was looking for a lazy solution , Scott thats a good article you found and will help me track down my problem I will use the resistance info in the motronic info "sticky" and try find the right readings from the ECU plug
Regards
Bill Black
_________________
1995 Grinnall Scorpion III(1990 K100 16v motor)
2010 KTM 450 EXC
Moto Guzzi V50 powered hovercraft !
1989 K100RS (8V) special edition
1974 Yamaha DT360
1972 Sanglas 400 T
1980 Yamaha XS110-Watsonian Palma sidecar
1966 Bridgestone 175 dualtwin
1980 BMW R100RS
1979 Bultaco sherpa T 350
1979 Yamaha DT175MX
1990 Honda XR250R

[Midlife K-risis]

Interesting topic. Ever since I bought my K1200RS the temp gauge hasn't been working. I took it to the dealer to troubleshoot and they said it was the temp sensor switch. They didn't have the part and they wanted an arm and a leg for the repair, so I took the bike home without having it fixed. So now it looks like I've been running with a too rich mixture !?! I never realized a broken temp sensor switch could affect so many things.
_________________
Silk Blue '94 K 1100 RS.

[Milton]

[chopper_harris]

HTH - Hope This Helps

My 1994 K11LT has two temp sensors :

A, Purple and Brown/Yellow wires to Motronic (This is the important one)
B, Black wire to the Temp Gauge

The Temp Gauge sensor is completely stand-alone, and has no bearing on engine management.

The resistance of both thermistors (senders) will fall as engine temperature rises. Do you have a multimeter ?
Measure across the terminals of sender A, and you should see it fall from typically a few hundred Ohms at room temp to a few tens of Ohms at operating temp.

HTH
_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

[duckbubbles]

When I did the K11 conversion to my K100, I went the cheap route and kept the original water temp sensor. Big mistake as they work differently. The bike was running so rich that someone following me commented that they could smell the gas. Plus the black cloud that came out when I got on it.

The combination with the K100 sensor told the computer that it was freezing all the time, hence the rich mixture.

Frank
_________________
85 K100/1100RS, 321,000 miles, 25 years
96 Ducati 900SS/SP, sold it
05 R1200ST, 35,000 miles, 5 years
400,000 BMW miles

[Midlife K-risis]

Yup, just checked with the BMW tech. The temp sensor for the temp gauge is seperate. Good!
_________________
Silk Blue '94 K 1100 RS.

[scottisha]

Hi Gents. Need a hand. Can I tell it like a story? My K11 temp gauge stopped working. Removed it, left a hole there. Stopped riding when I realised fan wasn't working anymore. Have pulled it all down now. Fan works fine on 12v. Must be missing a signal. From previous msgs, I have located the (hard to bloody get at) sensor on the pipe plumbing behind the radiator. That had a tricky connector (lever green from black & wiggle). I am putting this sensor back as fuel mixture seems good. Will replace dodgy sender in fuel pump, reinstall old temp gauge and see if the fan works when i am stopped at the lights. Will also replace thermostat while I have all this crap off the bike, or u know what will happen hey? If all this fails and I still cannot get fan on, then I will just put 12v through a relay, through a switch on dash and straight to the fan; bypass Mr. Motronic. I know when the fan needs to be on. I really do try to have patience with this electrical stuff. Anyway, does this seam like a good course, or anyone got somethin to add? Thanks gents.
_________________
Scottisha
k1100LT still workin on it
RF900R, fast is nice
XJ600, project, rustbucket

[flybd5]