6
Reassembly
Front Head Assembly
1. Using a 15-ton press, press the front head bushing into place. A hex flat must align with the front
head steel retainer.
2. Assemble the steel retainer spring and steel retainer plunger into the front head.
3. Assemble the steel retainer bolt bushings on each side of the front head. Set the retainer into the
retainer slot. To support the retainer, insert the retainer bolt through the bushings from the stopper
side of the front head.
4. Place the 3/4” nut and washer on the bolt. See the torque specifications chart for the torque setting.
Back Head Assembly
1. Place the chamfered side of the throttle valve stem guide into the back head and tap into position.
2. Ream the guide with a 0.312” (7.93 mm) reamer tool.
3. Set the throttle valve lever into the back head.
4. Place a 0.312” (7.93 mm) steel rod into the hole and hammer the pin in.
5. Apply a light film of grease on the rubber handle and slide onto the handle.
6. Assemble the plugs on both sides of the back head. See the torque specifications chart for the torque
setting.
7. Place the throttle valve o-ring in position where the cylinder will meet.
8. Insert the oil control felt onto the top portion of the back head and assemble the oil control plug.
Air Inlet Assembly
1. Place the #P91222 O-ring onto the air inlet swivel.
2. Place the #P91237 O-ring onto the air inlet swivel nut.
3. Assemble the air inlet swivel into the air inlet swivel nut and tighten the nut.
Complete Assembly
1. Stand the front head assembly in the vertical position.
2. Assemble the tappet seat and cylinder onto the front head, making sure the retainer nut and exhaust
port on the cylinder are in line with each other.
3. Place the front head bolts into the holes.
4. Assemble the front head bolt springs, front head lock washer, and tighten the front head bolt nut. A
minimum of three bolt threads should be visible.
5. Assemble the valve seat, valve, valve chest, and valve guide into the cylinder.
Note
: the valve chest
and valve guide must align with the knock placement. The valve has no orientation.
6. Install the valve chest dowel pin.
7. Install the five cylinder plugs into the cylinder.
8. Set the air inlet screen into the exhaust portion of the cylinder.
9. Install the air inlet assembly. See torque specification chart.
10. Place the throttle valve spring onto the throttle valve and install into the cylinder.
11. Lightly grease the inner diameter of the plunger, insert the plunger spring, and place on top of the
valve guide.
12. Place the back head on top of the cylinder and put the back head bolts from underneath into the four
holes.
13. Assemble the lock washer and fasten the back head bolt nuts. See torque specification chart for bolt
tightness.
14. Assemble the back head with the lever in line with the cylinder exhaust port.
15. Remove oil fill plug in the back head and refill the spindle oil tank.
16. Tighten oil tank plug. See torque specification chart.
17. Before operating a newly rebuilt tool, pour a few ounces of JET Marvel air tool oil into the air inlet.
