The BMW K75 & 100 from 1983

Manual - Chapter 2 Clutch

6. Release mechanism removal, examination and reassembly

Slacken the handlebar adjuster locknut, screw in the adjuster to gain the maximum cable free play and disconnect the cable from the operating lever on the gearbox.
The lever pivot pin is retained by a circlip at each end; remove the right-hand circlip and plain washer and pull the pivot pin out to the left. On models fitted with the side stand retracting mechanism the link rod nut must first be unscrewed so that the lever return spring pressure is released; the lever and spring can then be withdrawn with the pivot pin.
Slacken the clamp screw securing the rubber boot to the gearbox cover and withdraw the lever assembly, followed by the coil spring, the thrust piston, the thrust bearing and, on 100 models only, the clutch pushrod. These last three items can be removed using a suitable pair of pliers or similar, but if they prove to be awkward a piece of hooked wire or a strong magnet (the aluminium alloy pushrod has a steel cap and head) should be able to extract them. If they are bent or stuck fast; the gearbox must be removed to release them. Note that the rear wheel must be removed (100 models) only to permit the pushrod to be completely withdrawn.
On 75 models the push rod has a raised flange at its front end which bears against the clutch spring; it is therefore necessary to remove the gearbox (see Chapter 3 - Gearbox) before the pushrod can be withdrawn. Remove the clutch release components as described above, then tap the pushrod forwards out of the thrust bearing front race and pull it forwards out of the input shaft. On refitting, grease it thoroughly and push it very carefully backwards through the input shaft rear seal; a very thin layer of insulating tape wrapped around its tip would also help to protect the seal lips as the pushrod end passes through them. Hold the pushrod in place when it is fully inserted, remove the tape (if used) and use a hammer and a tubular drift such as a socket spanner to tap the bearing race on to its rear end. Lubricate the pushrod front end and clutch plate splines before refitting the gearbox.
Check all components, cleaning them thoroughly. The push rod must be straight; roll it on a flat surface such as a sheet of plate glass to check for any signs of warpage. Check that the rubber boot is undamaged and that the thrust bearing and piston are undamaged and in good condition. If any signs of wear or damage are found on any component it must be renewed.
Check the lever pivot bearings; if these are worn or corroded they must be driven out and renewed. Immerse the alloy lever in boiling water (taking due care to prevent any risk of injury) to ease the task of removal and refitting. Pack the lever bores with grease on reassembly.
Whenever the gearbox is removed, examine the condition of the pilot bearing bush in the engine output shaft rear end. This carries the front end of the push rod; if the push rod is a slack fit at any time, or if the bearing is otherwise damaged, it must be renewed. Lubricate it whenever the opportunity arises.
Reassembly is the reverse of the dismantling procedure. On 75 models fit the clutch pushrod as described above, then refit the gearbox (see Chapter 3 - Gearbox). On 100 models pack a small amount of lubricant via the seal into the input shaft; grease or oil the pushrod and refit it. On all models, oil the release bearing, the thrust piston and coil spring with gearbox oil as they are refitted.
Refit the rear wheel, if disturbed (100 models only). Connect the clutch cable and adjust the clutch as described in Routine Maintenance.