BMW R850 Maintenance Manual page 50

This is a non-stock, non-BMW approved method of placing the fuel filter outside
of the tank. Some others and I believe this to be safe if correctly accomplished by
a knowledgeable person using proper parts, procedures and tools. DO THIS AT
YOUR OWN RISK.
MATERIALS REQUIRED:
1. 6 ft of 5/16 (7.9 – 8.00mm) fuel injection hose. It is VERY important to ONLY
purchase fuel injection-rated hose since up to 42 psi exists in the fuel system! It's
expensive (~$4.00 per ft) but don't EVEN consider regular hose.
2. Original (expensive!) BMW filter or steel-bodied Deutsch FF401 or FF424 filter
(both Deutsch's are the same except for unneeded hose adapters/clamps with
the FF424) available at Auto Zone (~$2.00). The FF401/424 are for various and
sundry small and big car gas and diesel engines ranging up to MOPAR 440 cubic
inch V8s. Another suitable filter is the larger Deutsch FF507. DON'T use the
Fram G2 nylon-encased equivalent. The high 42 psi fuel pressure could burst a
non-metallic fuel filter case!
3. 8 fuel injection hose clamps, size 12.5 or 13mm (or inch equivalent). These
are the typical BMW style "squeeze together" clamps, NOT worm gear types.
Again, these are also available at BMW or auto parts stores. You only really need
6 of these since two on your bike are reusable, but 8 if you want all new
hardware.
4. Size 28 "Adel" aircraft cable clamp to belay the fuel filter to the transmission.
This clamp fits the Deutsch filter. A larger diameter clamp will be required for the
BMW filter since it's slightly wider. Clamps are available at some specialized
hardware stores, electrical shops, or alternatively the filter could be plastic cable-
tied (with rubber cushioning). I recommend a clamp.
5. New sealing "O" ring for the fuel pump assembly.
6. Longer brake line clamp screw, 4 x 22mm with ~3mm spacer
PROCEDURE (in accordance with tank and fuel filter removal/replacement steps
of the BMW or Haynes manual, plus those below):
PHOTOS: filter1, filter2, filter3, filter4, filter5
view photos at:
http://www.ibmwr.org/r-tech/oilheads/extern_fuel_filter.shtml
1. Drain (siphon dry) and remove the fuel tank. Don't forget to disconnect the two
electrical connectors! Observe and label which hose you removed from the tank
to each plastic fuel distribution line that goes between the cylinders (through the
engine from right to left). You'll also need to disconnect the two small rubber vent
lines at their unions above the right throttle body.
2. Remove the fuel pump assembly from the tank (six Allen screws).
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