A flaky HES will typically fail
when it heats up. A K bike will start and run just fine when
cold but will then suddenly quit once it heats up. After you
wait a few minutes the HES cools down so that the K will
start and run again.
The HES is located under a
rectangular cover on the front right of the motor:
The HES cover is held on to the
motor by five M6x20 bolts with a cork gasket:
Diagnosis - Cold:
Carry a bottle of cool/cold water
with you when riding. When the bike quits and won't start
right back up then try pouring water over the HES cover. If
the HES is failing then that should cool the HES to get the
bike running until the HES heats up again.
Diagnosis - Heat:
At home, take the HES cover off.
Be careful with the gasket when doing this. It's only a $4
part if you do mess it up though. BMW part 11141460307.
With the engine cold or cooled
down, start the bike and then see if you can induce a HES
failure using a heat gun or hair dryer.
All 4 cylinder Ks (K100, K1,
K1100) use the same HES, BMW part 12111459033. The two
sensors on it are 180 degrees opposed.
Having 3 cylinders, K75s use a
different HES with the sensors 120 degrees apart. BMW part
When replacing a HES, in order to
keep the engine timing correct, all you need to do is rotate
the HES to align the notch on the HES with the arced notch
on the engine block before tightening the bolts that hold it
© 2013 Drake Smith - Please do
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