Ducati Scrambler 800 - Service manual > Shimming the shafts

Before assembling the crankcase halves, it is necessary to calculate the shim that determines the end float of the crankshaft and of the gearbox shafts. Calculate the shimming following the procedures described below.

Shimming the crankshaft

After having installed the new main bearings proceed as follows to determine the total "SA" height of the shimming:

Measure value "LA" between the bearing supporting surfaces on the crankshaft;

Measure "LA1" and "LA2" corresponding to the distance from the mating surface between the crankcase halves to the mating surface of the bearing inner ring;

Add a pre-load of 0.30 mm to allow the axial-type bearings of the crankshaft to correctly settle in their seat.

The result will be: SA=LA-LA1-LA2-0.30.

The obtained result is the shimming value.

Reassembling the crankcase halves

The crankcase halves must be in good condition and perfectly clean. The mating surfaces must be perfectly flat and free from burrs.

Refitting the clutch-side crankcase half

The following parts must be present on the internal side of the crankcase half:

• the secondary shaft end bearing (12); apply grease on the bearing rollers. Drive the inner race (34), removed previously, fully home in the bearing. Apply grease to the inner race;
• the primary shaft bearing (13), secured with the screws (19) and the retaining spacer (17); apply recommended threadlocker to the screws (19), and tighten to a torque of 10 Nm (Min. 9 Nm - Max. 11 Nm);
• the roller bearing (16) with circlip (35) installed at the timing layshaft.

Refitting the generator-side crankcase half

The following parts must be present on the internal side of the crankcase half:

• the double-race ball bearing (11) supporting the selector fork shaft.

Apply threadlocker to the screws (20). Fit retainer plate (36) on gearbox secondary shaft bearing (11) starting the screws (20) on chain-side crankcase half.

Note The bearing retainer plate must be positioned with the holes tapering facing upwards.

Tighten the screws (20) to a torque of 10 Nm (Min. 9 Nm - Max. 11 Nm). The gearbox primary shaft end bearing (14) with inner spacer (21): apply grease on the bearing needle rollers.

Drive the inner race (37), removed previously, fully home in the bearing.

Apply grease to the inner race.

The main bearing (9).

The ball bearing (15) with circlip (36) at the timing layshaft, aiming it so that the plastic cage closed side is facing the crankcase half.

Note Bearings do not have a specific mounting position (except main bearings), however it is good practice to install the bearings so that the written side is facing inwards.

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