I spoke to a Kubota mechanic that has the service manual to my tractor and the D905 engine. He wrote down the proceedure.
Does this look right:
Valve Clearance Adjustment on D905:
Important: The valve clearance must be checked and adjusted when the engine is cold.
1. Remove the cylinder head cover and the glow plugs.
2. Align the "1TC" mark on the flywheel and alignment mark on the rear end plate so that the Number 1 piston comes to the compression top dead center.
3. Check the following valve clearance marked with a star using a feeler gauge.
Hand drawn chart:
Cylinder 1: Intake and Exhaust Valve
Cylinder 2: Exhaust Valve
Cylinder 3: Intake Valve
4. If the clearance is not within the factory specifications, adjust with the adjusting screw.
5. Then turn the flywheel 6.28 rad. (360 degrees), and align the "1TC" mark on the fly wheel and alignment mark on the rear end plate so that the Number 1 piston comes to the overlap position.
6. Check the following valve clearance marked with a star using a feeler gauge.
Hand drawn chart:
Cylinder 1: Already adjusted from first step.
Cylinder 2: Intake Valve.
Cylinder 3: Exhaust Valve.
7. If the clearance is not with factory specifications, adjust with the adjusting screw.
Factory intake and exhaust valve clearance (Cold):
0.145 mm to 0.185 mm
0.00571 in to 0.00728 in
Note:
- The sequence of the cylinder numbers is given as Number 1, Number 2, and Number 3 starting from the gear case side.
- After adjusting the valve clearance, secure the adjusting screw with the lock nut.
Does this sound right?
Also, what is the gear case side? Is it the side that is in front of the tractor or toward the rear of the tractor by the radiator and fan? I'm sure I'd figure it out when searching for the markings... but I'd like to ask, just in case.
Do I really need to remove the glow plugs? Or does that just aid in turning the engine to get TDC?