550RK (Seca/Euro)

Spark Plug

1. Check the electrode condition and wear, insulator color and electrode gap.

2.    Use a wire gauge for measuring the plug gap.

3.    If the electrodes become too worn, replace the spark plug.

4.    When installing the plug, always clean the gasket surface. Wipe off any grime that might be present on the surface of the spark plug, and torque the spark plug properly.

Clutch and Oil Pump


1. Remove right crankcase cover.

2. Release the tension evenly on the 6 mm bolts and remove the clutch pressure plate and clutch springs.

3.    Remove the friction plates and clutch plates.

Clutch Adjustment

Free play adjustment

a.   Loosen either the handlebar lever adjuster lock nut or the cable length adjuster lock nut.

b.  Turn the cable length adjuster either in or out until proper lever free play is achieved.

Clutch lever free play:

2 - 3mm (0.08 ~ 0.12 in)

Transmission Assembly

1. Upper crankcase

a. Install the connecting rods onto the crankshaft with the proper connecting rod bearings and apply molybedenum disulfide grease to the bolt threads. Apply torque evenly to both ends of the cap.

Cam chain, cam sprockets and chain tensioner.

a. Rotate each cam shaft until the dot on the cam is aligned with the arrow on the center cam cap.

Use extreme caution when rotating the cams. Two possible dangers exist. First, the wrench may contact the head and fracture it. Or second, a valve may become bent if the cam is turned the wrong way.

Valve spring and lifters

1. Checking the valve springs

a.   This engine uses two springs of different sizes to prevent valve float or surging. The valve spring specifications show the basic value characteristics.

Drive Chain and Wheels

Drive chain

1. Drive chain tension check

Before checking and/or adjusting, rotate the rear wheel through several revolutions and check the tension several times to find the tightest point. Check and/or adjust chain tension with rear wheel in this "tight chain" position.

Ignition Timing

1. Ignition timing is checked with a timing light by observing the position of the stationary pointer and the marks stamped on the timing plate.

The timing plate is marked as follows:

"n"— Firing range for No. 1 (L.H.) cylinder

"T" ....Top Dead Center for No. 1 (L.H.) and No. 4 (R.H.) cylinders.

2.    Connect the timing light to No. 1 (L.H.) spark plug lead wire.

Oil Pump and Clutch

Oil pump

1. Check the clearance between housing and outer rotor.

Standard clearance:

0.09 ~ 0.15 mm (0.0035 ~ 0.0059 in)

2. Check the clearance between outer rotor and inner rotor.

Standard clearance: 0.03 ~ 0.09 mm (0.0012 ~ 0.0035 in)

3. Check the plunger for scrathces and wear.

Fuel Petcock

If the fuel petcock is
leaking or excessively contaminated, it should be removed from the fuel
tank and inspected.

Remove the fuel tank and position it so that fuel will not spill when
the petcock is removed.

Remove the petcock and inspect the filter screen. Replace the filter if
seriously contaminated.