Rotax "C" Gear Box - Gear Drive
1. Clean and degrease the
crankshaft end and mounting holes on the crankcase before starting.
2. Using the Rotax fixation tool
(876 640) supplied in the Rotax tool kit lock the engine up by
installing the pin into the impulse hole, used to run the fuel pump.
With the pin in place rotate the engine, until it locks.
3. Install flywheel onto
crankshaft end. Install flat washer onto bolt install bolt.. Torque to
45 FOOT lbs.
4. Install allen screws with
washers into hardee disc. Install Hardee disk onto crankshaft as
shown. Use loctite 242 on bolt threads. Toque to 30 FOOT lbs. While
torqueing use a 17 mm wrench to prevent special flat sided washers
5. If Hardee disc is banded
6. Install back half of gear box
housing onto engine with the 8 bolts provided. Apply loctite 242 to
bolt threads before installing. Torque to 195 INCH lbs.
7. Install #16 shims onto the
8. Install anti-seize compound
onto pinion shaft, and install #4 coupling flange.
Torque allen bolt
located in the center of the flange to 195 INCH lbs.
9. Install gasket (#21) - install
front gear box housing and prop shaft onto rear housing. Torque all 6
mm fasteners in an X pattern to 95 INCH lbs.
10. Remove fixation tool from
11. Fill gear box with 90 weight
oil until oil runs out the lower of the two side plugs (about 4
12. Tighten then safety wire top
and bottom plugs.
13. Tighten then safety wire vent
cap and drain plug.
the Rotax "C" drive gear box, lubrication oil level is very
critical. When servicing, fill slowly to the lower of the two
screw holes on the side of the case (#39), and then replace the
screw and washer, and safety wire the two oil level screws.
On new gear boxes, change oil after the first 10 hours of
operation and then every 100 hours after that.
Rotax redrive gears must always be replaced together, this is
because of the gears have worn together as a unit and replacing
one would only result in premature wearing of the both gears.
The two large holes on the side of the Rotax "C" drive gear box,
(where you can look in and see the rubber coupler) are for cooling
of the rubber shock mount, inside the drive system and must be
there is evidence of gear oil on the bottom of the gear box where
it meets the crankcase, or in the two holes referred to above this
could indicate a failed seal (#13) inside the gear box.