Complete Suzuki C50 Boulevard Clutch Assembly Diagram and Parts Guide 2009 Model
For accurate hydraulic assembly repairs, start with a raw layout centered on the pressure plate springs. Identify the primary three coils by their 3.2 mm wire diameter–these sit closest to the basket hub. Measure the free length at 35.4 mm; if compression exceeds 2 mm, replace all springs as a set to avoid uneven release tension. Beyond the springs, trace the steel drive plates: six identical segments, 1.6 mm thick, marked on edge with factory etch codes.
Remove the basket nut first using a 27 mm socket locked against the starter gear rotation. Once loose, note the alignment notch on the basket’s back face–it must realign precisely with the countershaft spline index during reassembly. The basket’s taper bore houses two angular contact bearings; inspect the inner race for brinelling marks wider than 0.3 mm before proceeding.
Focus next on the friction discs. The four friction-coated plates carry grooves at 60° spacing; verify groove depth at 0.8 mm minimum. Behind these, the fiber separator plates–each 1.2 mm thick–nest against the backing flange. Any warping beyond 0.05 mm requires full replacement. Label all components left-to-right during disassembly to prevent mis-stacking during rebuild.
Pay specific attention to the thrust washer positioned between the final friction disc and the pressure plate. Its chamfered edge faces outward; reversing the washer risks clutch drag under partial engagement. The thrust ring diameter measures 108 mm, and its lubrication channel must remain unobstructed–flush with compressed air before installing the new friction surfaces.
Seal examination centers on the input shaft O-ring. The silicone compound used hardens at 15,000 miles; replace with the updated fluorocarbon variant PN 31476-13A00 to prevent premature weepage. Torque the basket nut to 85 Nm only after confirming the snap ring sits flush within its groove; improper seating leads to catastrophic basket spin-out.
Understanding the Internal Power Transfer Components of the M-Series Twin
Begin by locating the pressure plate assembly behind the engine’s left-side cover. The diaphragm spring–distinctive for its conical shape and six radial fingers–applies consistent force through the friction discs against the steel plates. Remove the cover bolts in a cross-pattern sequence (torque: 18-22 Nm) to avoid warping. Inspect the diaphragm fingers for uneven wear; grooves deeper than 0.3 mm indicate replacement.
- Primary drive gear (tooth count: 32) meshes with the basket’s internal splines, transmitting torque via ten friction discs (paper-based, thickness: 2.9 mm ±0.05 mm) sandwiched between eleven steel plates (thickness: 1.7 mm ±0.02 mm).
- The basket’s outer diameter wears at 84.5 mm; measure with calipers at three points; deviation beyond ±0.1 mm requires machining or replacement.
- Thrust washers (two pairs) sit between the basket and hub; verify thickness (0.8 mm nominal) and replace if scoring exceeds 0.1 mm depth.
Disassemble the hub by aligning match marks on the basket and hub to preserve balance. The hub’s six internal ramps cooperate with fifteen steel rollers (diameter: 8.0 mm); lubricate with high-tack moly grease (NLGI #2) before reassembly. Check roller paths for pitting; rollers must spin freely without axial play (±0.05 mm tolerance).
Reinstall components in reverse order: hub → basket → friction stack → pressure plate. Tighten the center nut (torque: 80-90 Nm) while holding the hub stationary using a strap wrench on the basket’s outer teeth. Prevent basket rotation by engaging a gear on the primary shaft–failure risks incorrect indexing.
Bleed the hydraulic system through the master cylinder bleed nipple (located aft of the lever mount). Use DOT 4 fluid; avoid silicone-based alternatives. Pump the lever slowly, maintaining a 30-second pause between pumps to allow fluid displacement. Air bubbles smaller than 1 mm diameter at the nipple exit indicate completion.
Avoid excessive lubricant on friction discs. Residual oil reduces engagement efficiency, evidenced by 2-3 mm slip at 3500 RPM under 75% throttle load. Final test: measure lever pull effort (1.2-1.5 kgf); deviation suggests misalignment or improper spring preload–recheck diaphragm seating angle (82° ±1°).
Identifying Power Transmission Unit Parts in Factory Repair Documentation
Begin by referencing section 6-3 of the official workshop guide. The friction mechanism breakdown is illustrated on page 187, with exploded views of all interfacing components. Locate figure 6-12 for a clear depiction of the pressure plate, friction discs, and basket assembly relative to the engine casing.
Primary components occupy these positions:
| Component | Manual Reference | Visual Identifier | Typical Location |
|---|---|---|---|
| Drive basket | 6-3.1 | Splined outer hub | Left engine half, behind alternator cover |
| Driven plates | 6-3.2 | Metallic discs with friction material | Nested inside basket, alternating with steel discs |
| Pressure plate | 6-3.3 | Annular plate with spring posts | Outermost stack component, contacting release mechanism |
| Clutch push rod | 6-3.4 | Slender cylindrical shaft | Extends through transmission main shaft |
Trace the actuating mechanism via illustration 6-15. The release bearing sits at the base of the clutch lever arm, pressing against the diaphragm spring when engaged. Verify proper alignment by checking that the spring fingers compress evenly under hand pressure.
For internal inspection, remove the left crankcase cover (part 11 in section 5-2). Four 8mm bolts secure the cover–loosen in a diagonal pattern. Behind it, the basket retaining nut (torque spec: 65 Nm) requires a 27mm socket for removal. The factory manual labels this fastener as item 6-7.
Inspect the friction pack thickness using calipers. Minimum service limits appear on page 203–1.5mm for driven plates, 1.8mm for steel separators. Record measurements before disassembly to determine wear patterns.
Troubleshooting Common Assembly Errors
Misalignment often stems from improper stacking order. Steel separator plates always alternate with friction discs, beginning with a steel plate adjacent to the basket. Reassemble with dry components, applying fresh lubricant only to the push rod and bearing surfaces.
Adjust free play by referencing specification 3-1.1.0. Turn the adjuster at the lever pivot until 2-3mm of slack remains. Confirm smooth operation by rotating the wheel–resistance should increase steadily without sudden engagement or drag.
Step-by-Step Guide to Removing the Transmission Basket on Your Middleweight Cruiser
Start by securing the engine unit in a vise with protective jaws, positioning it horizontally to access the primary cover bolts. Remove all 12 fasteners (M6 x 25mm) in a cross pattern using a 10mm socket–keep them sorted by length, as three differ for mounting points near the alternator. Once detached, tap the cover gently with a rubber mallet to break the gasket seal; avoid prying to prevent warping the aluminum surface. Drain the residual fluid into a catch pan, noting any metallic particles that may indicate worn friction plates.
Locate the pressure plate assembly beneath the basket–it’s held by six springs and corresponding bolts, each torqued to 18 ft-lbs. Use a spring compressor or improvise with two large zip ties to compress the springs evenly before removing the bolts to avoid uneven tension. Slide the pressure plate off, then inspect the basket’s splines for burrs or gouges; a light pass with 800-grit emery cloth can restore smooth engagement if minor wear is present. Rotate the basket by hand while checking for lateral play–excess movement suggests bearing failure, requiring replacement before reassembly.
To separate the basket from the input shaft, lock the gearset in gear (use a screwdriver through the inspection port if needed) and loosen the central nut with a 30mm socket and breaker bar–this nut is often secured with thread locker and torqued to 70 ft-lbs. Once removed, the basket should slide off freely; if stuck, apply heat via a propane torch to the hub area (targeting 200°F) to expand the metal without damaging adjacent components. Label all disassembled parts, including washers and thrust bearings, as their orientation affects alignment during reassembly.
Pinpointing High-Friction Zones in Mid-Displacement Touring Bike Friction Discs
Examine the inner and outer friction surfaces under a 10x loupe for glazing, scoring, or discolored streaks–each streak wider than 1.5 mm signals localized heat buildup from slippage. Replace any disc displaying three or more streaks; Suzuki service bulletin M08-12 specifies a maximum allowable cumulative streak length of 8 mm per surface. Measure remaining material at three equidistant points using a ball-end micrometer: discs thinner than 2.8 mm trigger immediate replacement, while those between 2.8–3.1 mm demand closer inspection every 800 miles.
Thermal Stress Indicators Beyond Thickness
Probe steel separator plates for warpage exceeding 0.1 mm–use a straightedge and feeler gauges at six radial points; any deviation above tolerance suggests uneven pressure distribution. Inspect spline engagement grooves on both friction discs and pressure plate hub: burrs taller than 0.2 mm or wear patterns deeper than 0.3 mm necessitate machining on a vertical mill with a 60° chamfer cutter. Thermal damage often manifests as a blue-black oxide film; a single swipe with 600-grit wet paper on affected zones reveals whether the substrate remains intact or requires full replacement.