Air Filter:

Use BMW part 13721460337 or Mahle LX 75

Service Interval: The BMW recommended replacement interval for the air filter is 12,000 miles. This is way too low. I replace air filters every 50,000 miles and think even that is too often. The air filter is very oversized for a 0.75 or 1 liter motor.

K&N Air Filter: Don't. The K bike air filter is better and lets less dust through. Since the K bike air filter is so oversized a K&N filter will not add horsepower or doing anything else magical that the K&N marketing claims. K&N recommends cleaning and re-oiling every ten thousand miles. Since the K bike engine compartment gets so hot, the K&N oil may dry faster than normal and require even more frequent maintenance. Throw the K&N air filter away and keep the cool sticker that came with it.

I don't have a bone to pick with K&N. In fact, I use K&N air filters in one of my cars. They make a good product that is worthwhile for some vehicles but a K bike isn't one of them.

 

Once you have removed whatever right side fairing parts might be in the way:

Airbox clamps:

It's a tight squeeze to lift the rear of the airbox to get the air filter out but there's a way to get some leverage:

If you're just replacing the air filter then this is as far as you need to go. The air filter will slide in a lot easier if you put some Armor All in the grooves at the edges on the top and bottom of the air filter.

Hose clamps at front of airbox:

If you're just trying to get to the fuel pressure regulator or temp sensor then you don't need to bother undoing the 72mm hose clamp. You can skip over the mass air flow sensor instructions if you click here.

 

Mass airflow sensor:

Removing MAF:

MAF connector:

 

Access Fuel Pressure Regulator & Temp Sensor:

 

Bottom half of airbox:

Sometimes it takes a little wrangling to get the bottom half out once the two bolts are removed. This is normal.

As a matter of interest, once the bottom half of the air box is removed, there's a casting date for the engine block in the right rear corner. This block was cast in the latter part of 1994.

Airbox removed:

 

Temp Sensor:

BMW part # for K75/K100: 61311459197

Bosch part #: 0280130032 or 0280130069

(Same part but less expensive)

 

Here's the location of the temp sensor without the radiator hose in the way:

Similar to the fuel injectors, the temp sensor connector has a wire clip around it that needs to be picked off in order to remove the connector:

Once you have the connector removed from the temp sensor, put the wire clip back on the connector. When you push the connector back on the wire clip just slips over the two nubs on the sides of the temp sensor to lock the connector in place.

Loosen and replace the temp sensor. Have the new one ready to install quickly as some coolant will come out when you remove the old one. You may want to consider draining the coolant before removing the temp sensor if the coolant hasn't been changed in a while.

If you do replace the temp sensor without draining the cooling system then do not loosen or remove the radiator cap or the coolant will gush out when you remove the temp sensor.

The torque for temp sensor installation is: 9 Nm (80 in-lbs, 6.6 ft-lbs)

 

© 2022 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.