550RH (Seca/Euro)

Camshaft, chain and sprockets

1. Camshaft

a.   The cam lobe metal surface may have a blue discoloration due to excessive friction. The metal surface could also start to flake off or become pitted.

b.   If any of the above wear conditions are readily visible, the camshaft should be replaced.


A. Battery

1. The fluid level should be between the upper and lower level marks. Use only distilled water if refilling is necessary.

Normal tap water contains minerals which are harmful to a battery; therefore, refill only with distilled water.

Pick-up coil, Generator and Starter

Pick-up coil assembly

1. Remove the alien bolt that holds the timing plate.

2. Remove the pick-up coil securing screws and remove the pick-up coil assembly.


Insufficient compression pressure will result in performance loss and may indicate leaking valves or worn or damaged piston rings. Procedure:

1.    Make sure the valve clearance is correct.

2.    Warm up the engine 2^3 minutes.

3.    Remove all the spark plugs.

4.    Install a compression check gauge.

Crankcase Assembly

Crankcase assembly

a. Apply Yamaha bond # 4 sealant or equivalent to the crankcase mating surface. Be very careful not to allow any sealant to come in contact with the oil gallerly "O-ring" and crankshaft bearings. It is extremely important, however, that sealant be applied around the case stud holes. Apply sealant to within 2~3 mm (0.08 - 0.12 in) of the bearings.

AC Generator, Starter Motor and Pickup coil


a. Install the rotor onto the shaft and tighten the bolt using the rotor holding tool (special tool) as shown.

1. Rotor holding tool

Tightening torque: 3.5 m-kg (25.5 ft-lb)

b. Install the stator coil assembly onto the crankcase and align the grooves on the stator core with the bolt holes on the crankcase.

Headlight and Taillight


1. Headlight bulb replacement

a. Remove the cowling assembly.

b. Remove the 2 screws holding the light unit assembly to the headlight body.


Crankcase disassembly

1.    Remove the right-front crankcase cover.

2.    Remove the upper crankcase bolts, starting the highest numbered bolt.

Turn over the engine and remove the lower crankcase bolts.



Cylinder head and Camshafts

a. Install the new cylinder head gasket. Install the dowel pins and "o-rings".

b.   Install the cylinder head onto the cylinder. Pull the cam chain through the cylinder head as it is installed. Tie the cam chain so that it does not fall into the crankcase.

Transmission, Starter clutch and Seals

Inspect each shift fork signs of galling on gear contact surfaces. Check for bending. Make sure each fork slides freely on its guide bar.

2.    Roll the guide bar across a surface place. If the bar is bent, replace.

3.    Check the shift cam grooves for signs of wear or damage. If any profile has excessive wear and/or damage, replace cam.