Scramblers owners and service manuals


Ducati Scrambler 800 - Service manual > Shimming the shafts

Engine / Crankcase: casings / 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;

Crankcase: casings

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;

Crankcase: casings

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.

Crankcase: casings

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:

Crankcase: casings

Refitting the generator-side crankcase half

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

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.

Crankcase: casings

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.

See also:

 Ducati Scrambler 800 - Service manual > Closing the crankcase

If previously removed, apply specified threadlocker to dowel (28) and tighten to a torque of 15 Nm (Min. 13 Nm - Max. 17 Nm). After tightening, remove the excess of threadlocker.

 Ducati Scrambler 800 - Service manual > Main bearings

To replace the bearings proceed as follows: heat the crankcase half in an oven to 100 ВєC; remove the bearing using a drift and hammer; install the new bearing (while the crankcase is still hot) keeping it perfectly square in its seat using a tubular drift that only bears on the outer ring of the bearing; allow the parts to cool and check that the bearing is securely fastened to the crankcase half.

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