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I have a 2000 k1200rs and the gas mileage has dropped from around 40 mpg to 30 mpg.92,000 miles, fresh valve adjust, fresh air cleaner and new correct plugs. Runs and starts great. No smoke. anybody got a suggestion?
 

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O2 sensor.There is a much cheaper NTK with the correct specs and terminal that I have been using rather successfully for the last couple years.I don't have the part number with me.Sailor might have noted it?

Other than that and at that milleage,time to pull the fuel injectors and send them somewhere for an ultrasonic cleaning and balance test.
 

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Q

I installed the approved NTK 02 sensor and noted no difference, but as it turned out the sensor was not the cause of trouble on my 30kmile 2010 K1300GT. IIRC I got the new sensor on sale from Euro Motoelectric, along with four coils and plugs, none of which helped. In the end, it was the fuel pressure sensor on the fuel rail that had faulted. The dealer's tech discovered this by connecting a fuel pressure gage to the fuel line - very old school.

I spoke at length with the dealer tech about the electrical and mechanical functions of the bike. He confirmed there is no customer-available technical information and that the present course of BMW Motorrad is to turn dealer mechanics into parts replacers, dependent on verifiable connection of customer bikes to Motorrad HQ.

The bike runs an alpha-n injection system, meaning that the prime parameters input to the ECU are throttle position sensor and crank speed. Injector opening duration (pulse width) is modified by the intake air temp, local barometric pressure, and coolant temp. The fuel pump runs constantly and provides constant fuel pressure. The fuel sensor only verifies correct, constant pressure. The ECU has no ability to recognize engine load. When the engine comes under load, the rpm will drop unless the operator increases throttle opening.

I have been told by a person whose information is believed good, that resistor tuning devices ceased to be useful/appropriate a decade ago. That person did not further qualify his statement.

OP, my bike (also) gets at or just under 30 mpg on 87 octane at sea level town driving at ambient temps in the 80s-low 90s. OTOH I live on an island of a million people and even more cars, that is only 20 miles long and 30 miles wide.
 

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Mr.Honolulu,this subforum is about the classic Ks with the brick engine not the later slant-K
No fuel pressure sensor aka the FPC or coil sticks on them old Ks.
 

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NGK/NTK 25542 is the aftermarket O2 sensor that is correct for the K1200RS.Has the right "specs" to function with the Motronic and the right connector to make it "plug&play"......!

Should be available from most Autoparts?Best price was on fleabag then at around $70.00 usd.
 

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Discussion Starter #8
I can get an OEM Bosch sensor for $140 or an NTK from Summit Racing here in Sparks NV for $104. Would the extra $ for OEM be worth it.
 

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Discussion Starter #9
There is also a Bosch sensor available from Magnum Tuning that has to be spliced in for only $64. Sounds like a good option to me.
 

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NTK was OEM on my 03.The Bosch universal type I installed/spliced in back then never worked properly.The sensor function was fine once fully warmed up but the heater resistance specs wrong for our Motronic so the heater wasn't doing its job and it could take up to 10 minutes of running for the sensor to kick in.And rather erratically at that.End result is increased whitish deposits on the plugs or valves.

It is possible that one of the many offered Bosch universals is matched to the OEM NTK.Mine wasn't so it took me a while to find the correct NTK but I was successful.
 

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Discussion Starter #11
Thanks to all for the Oxygen sensor tip. I went with an OEM Bosch and mileage immediately went back up to 45 along with better running in general.
 
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