Valve adjustment, initial engine check

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Timing Chain Adjuster

• Depress the latch with your finger, this will release the one-way design of the adjuster
• with the latch released push the plunger back in the body.

• Bolt the adjuster body into the head, it will only fit one way Torque to 10Nm or 7.2 ft lbs
• Take the spring and hollow bolt and insert them into the body of the adjuster
• you will hear the adjuster working as the spring is insterted
• Keep pressure on and screw in the bolt
• No need to do anything further the adjuster is automatic, when the spring is insterted the plunger pushes on the timing chain rail with takes up the slack, whenever there is slack the spring will push it out more and lock it.

Torque the main bolt to 22Nm or 16ft lbs.
How tight this bolt is has no correlation to how tight the timing chain is. so dont over tighten or leave loser than specs.

 

Since the motor is almost entirely reconstructed at this point we need to double check things. Give the motor quite a few turns at the crank, go through all revolutions a few times and listen for any wierd noise, any resistance other than the slight compression (remember the decompression mechanism will be engaged so dont be scared when it spins over relatively easily) With the Valve cover covers off watch the valves so you can see where you are in the cycle of a 4 cycle engine.

• Intake Stroke - Intake valves open, then close at BDC (bottom dead center)
• Compression Stroke - All valves are closed until the piston reaches TDC (top dead center - timing mark at crank is veiwable)
  
• Power Stroke - All valves are closed until the piston reaches BDC
• Exhaust Stroke - Exhaust valves are open and piston pushes up to TDC

Once you are satisfied everything internal is working correctly, go through one more time and stop on the compression stroke at TDC. We will now adjust the valves. They will need adjusted again once the machine has a few hours on it.

 

AT TDC ON THE COMPRESSION STROKE!

• Use a feeler guage of the correct size try and stick it under the tappet as in the picture. Its best to bend the guage slightly so that the gauge being bent doesnt interfere with the readings. If the setting is right you will feel slight drag when trying to move the guage in and out.

Valve Settings - Cold
Intake 0.10~0.15mm (0.0039~0.0059 in)
Exhaust 0.15~0.20mm (0.0059~0.0079 in)

Adjusting the valves

• if you find adjustment is needed loosen the 10mm keeper nut on the tappet.
• Use needle nose to turn the tappet tighter or looser.
• Tighten the keeper nut, I go pretty tight on these and I dont use any locktite. It will be hard to torque these without special tools.
• you will find that you will have to hold the tappet while tightening aswell as compensate for the tappet turning when tightening the nut - practice makes perfect. This is why I recommend adjusting the intakes first.

Yamaha recommends a torque of 14Nm or 10ft lbs

 

Repeat for the exhaust valves, then give the motor one complete "cycle" and back to TDC on the compression stroke, then recheck both intake and exhaust clearances.

Then install the "tappet covers" as yamaha calls them. I just call them the valve cover-covers
Torque the allen bolts to 11Nm or 8ft lbs