All K bike gas tanks have two
vent pipes protruding from underneath the right middle rear of the
Oftentimes these are connected to two hoses. The
forward hose, from the factory, went to a vent on the top of
the engine block above the middle of the timing cover. This
was so that gas/fumes would vent back into the engine to
meet California emissions requirements. The rear hose is
from the left side of the gas cap. It drains of water from
around the gas cap when it's raining. The hose from that
drains to the ground inside the rear of the right peg plate.
Many times the vent on the front
of the engine has been capped or the hosed plugged since it
really doesn't do anything.
These hoses can be a pain to keep
connected and also keep unkinked when re-installing the gas
tank. An alternative is to install "The Cup" under those two vent
pipes. (BMW part 16132307467
- Air Accumulator - about $5)
Attach a hose to the pipe at the base of the cup
to drain behind/under the right side peg plate. You can
reuse the old hose from the rear pipe for this. It already
follows the correct path.
Here's what the part looks like:
To keep it in place, drill a hole
in it and use a zip-tie to hold it to the frame:
The upside of doing this is that
it makes tank removal and installation much easier and you
don't have to worry about those vent hoses getting kinked.
The downside of doing this is that you might occasionally smell
a whiff of gas when riding. Big deal.
© 2021 Drake Smith - Please do
not use or reproduce this elsewhere. Feel free to link
to it though.