ENGINE
131
duced during the honing operation. Repeat this step
108
until all of the valve guides are thoroughly cleaned.
Then rinse the cylinder head and valve guides in
clear, cold water and dry with compressed air.
12. After cleaning and drying the valve guides, ap-
ply clean engine oil to the guides to prevent rust.
13. Resurface the valve seats as described in Valve
Seat Reconditioning in this chapter.
4
Valve seat width
Valve Seat Inspection
1. Remove all carbon residue from each valve seat.
Then clean the cylinder head as described under
Valve Inspection in this chapter.
NOTE
The most accurate method of check-
d.
Continue to rotate the reamer until the entire
ing the valve seat width and position
bit has traveled through the valve guide and
is with machinist’s dye.
the shank of the reamer rotates freely.
2. Check the valve seats in their original locations
CAUTION
with machinist’s dye as follows:
Never back the reamer out through
a. Thoroughly clean the valve face and valve
the valve guide as the guide will be
seat with contact cleaner.
damaged.
b. Spread a thin layer of Prussian blue or ma-
e.
Remove the T-handle from the reamer. Re-
chinist’s dye evenly on the valve face.
move the reamer out from the combustion
c. Insert the valve into its guide.
chamber side of the cylinder head.
d. Support the valve by hand (Figure 107) and
f.
Apply low-pressure compressed air and clean
tap the valve up and down in the cylinder
out the small shavings from the valve guide
head. Do not rotate the valve or a false read-
bore. Then clean the valve guide bore with the
ing will result.
small spiral brush.
e. Remove the valve and examine the impres-
9.
Hone the valve guide as follows:
sion left by the machinist’s dye. The impres-
a. Install the valve guide hone into a high-speed
sions on the valve and the seat must be even
electric drill.
around their circumferences and the width
b. Lubricate the valve guide bore and hone
(Figure 108) must be within the specifica-
stones with the reamer lubricant—do not use
tions in Table 2. If the width is beyond the
motor oil.
specification or if the impression is uneven
c. Carefully insert the hone stones into the valve
recondition the valve seats.
guide bore.
3. Closely examine the valve seat in the cylinder
d. Start the drill and move the hone back and
head (Figure 93). It must be smooth and even with a
forth in the valve guide bore for 10 to 12 com-
polished seating surface.
plete strokes. Work for a 60° crosshatch pat-
4. If the valve seat is in good condition, install the
tern.
valve as described in this chapter.
5. If the valve seat is not correct, recondition the
10. Repeat for each valve guide.
valve seat as described in this chapter.
11. Soak the cylinder head in a container filled with
hot, soapy water. Then clean the valve guides with a
valve guide brush or an equivalent bristle
Valve Seat Reconditioning
brush—do not use a steel brush. Do not use clean-
ing solvent, kerosene or gasoline as these chemicals
Valve seat reconditioning requires considerable
will not remove all of the abrasive particles pro-
expertise and special tools. In most cases it is more
132
CHAPTER FOUR
economical and practical to have these procedures
performed by an experienced machinist.
109
The following procedure is provided for those
equipped to perform the task. A valve seat cutter set
(HD-35758A) or equivalent is required. Follow the
manufacturer’s instructions.
Refer to Figure 109 for valve seat angles. While
Cylinder head
the valve seat angles for both the intake and exhaust
valves are the same, different cutter sizes are re-
Seat
quired. Also note that a 45-degree seat angle is
Valve
specified when grinding the seats, while a
60°
46-degree seat angle is specified when cutting seats.
0.040-0.062 in.
1. Clean the valve guides as described under In-
(1.02-1.57 mm)
spection in this chapter.
2. Carefully rotate and insert the solid pilot into the
valve guide. Make sure the pilot is correctly seated.
31°
46° cutting
45° grinding
Margin
CAUTION
Valve seat accuracy depends on a cor-
rectly sized and installed pilot.
3. Using the 45-degree grinding stone or 46-degree
cutter, descale and clean the valve seat with one or
two turns.
8. Reinsert the solid pilot into the valve guide. Be
certain the pilot is properly seated. Install the 31°
CAUTION
cutter onto the solid pilot and lightly cut the seat to
Measure the valve seat contact area in
remove 1/4 of the existing valve seat.
the cylinder head (Figure 108) after
each cut to make sure its size and area
9. Install the 60° cutter onto the solid pilot and
are correct. Over-grinding will sink
lightly cut the seat to remove the lower 1/4 of the
the valves too far into the cylinder
existing valve seat.
head, requiring replacement of the
10. Measure the valve seat with a vernier caliper.
valve seat.
Then fit the 45° grinding stone or 46° cutter onto the
4. If the seat is still pitted or burned, turn the cutter
solid pilot and cut the valve seat to the specified seat
until the surface is clean. Work slowly and carefully
width in Table 2.
to avoid removing too much material from the valve
11. When the valve seat width is correct, check
seat.
valve seating as follows.
5. Remove the pilot from the valve guide.
12. Remove the solid pilot from the cylinder head.
6. Apply a small amount of valve lapping com-
13. Inspect the valve seat-to-valve face impression
pound to the valve face and install the valve. Rotate
as follows:
the valve against the valve seat using a valve lap-
a. Clean the valve seat with contact cleaner.
ping tool. Remove the valve.
7. Measure the valve seat with a vernier caliper
b. Spread a thin layer of Prussian Blue or ma-
(Figure 108 and Figure 109). Record the measure-
chinist’s dye evenly on the valve face.
ment to use as a reference point when performing
c. Insert the valve into its guide.
the following.
d. Support the valve with two fingers and turn it
with the valve lapping tool.
CAUTION
The
31° cutter removes material
e. Remove the valve and examine the impres-
quickly. Work carefully and check the
sion left by the Prussian blue or machinist’s
progress often.
dye.
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ENGINE
133
Valve Lapping
110
If valve wear or distortion is not excessive, at-
tempt to restore the valve seal by lapping the valve
to the seat.
After lapping the valves, install the valve assem-
Port
blies and test each valve seat for a good seal by
pouring solvent into the ports (Figure 110). If the
Solvent
seal is good, no solvent will leak past the seat sur-
or
4
kerosene
face. If solvent leaks past any seat the combustion
chamber will appear wet. Disassemble the leaking
valve and repeat the lapping procedure or recondi-
tion the valve as described in this chapter.
1. Smear a light coating of fine grade valve lapping
compound on the seating surface of the valve.
2. Insert the valve into the head.
3. Wet the suction cup of the lapping tool and stick
Combustion
it onto the head of the valve. Lap the valve to the
Valve
chamber
seat by spinning the tool between both hands while
lifting and moving the valve around the seat 1/4 turn
at a time.
4. Wipe off the valve and seat frequently to check
the progress. Lap only enough to achieve a precise
f. Measure the valve seat width (Figure 108 and
seating ring around the valve face.
Figure 109). Refer to Table 2 for the correct
5. Closely examine the valve seat in the cylinder
seat width.
head. The seat must be smooth and even with a pol-
g. The valve seat contact area must be in the
ished seating ring.
center of the valve face area.
6. Thoroughly clean the valves and cylinder head
14. If the contact area is too high on the valve, or if
in solvent to remove all grinding compound resi-
it is too wide, cut the seat with the 31° cutter. This
due. Compound left on the valves or the cylinder
will remove part of the top valve seat area to lower
head will cause rapid engine wear.
or narrow the contact area.
7. After installing the valves into the cylinder head,
15. If the contact area is too low on the valve, or
test each valve for proper seating. Check by pouring
if it is too wide, use the 60° cutter and remove part
solvent into the intake and exhaust ports. Solvent
of the lower area to raise and narrow the contact
must not leak past the valve seats. If leakage occurs,
area.
the combustion chamber will appear wet. If solvent
16. After obtaining the desired valve seat position
leaks past any of the seats, disassemble that valve
and angle, use the 45° grinding stone or the 46° cut-
assembly and repeat the lapping procedure until
ter and very lightly clean off any burrs caused by the
there is no leakage.
previous cuts.
17. When the contact area is correct, lap the valve
Valve Seat Replacement
as described in this chapter.
18. Repeat Steps 1-17 for the remaining valve
Valve seat replacement requires considerable ex-
seats.
perience and equipment. Refer this work to a
19. Thoroughly clean the cylinder head and all
Harley-Davidson dealership or machine shop.
valve components in solvent, then clean with deter-
gent and hot water and rinse in cold water. Dry with
compressed air. Then apply a light coat of engine oil
CYLINDER
to all non-aluminum metal surfaces to prevent rust
formation.
Refer to Figure 111.
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134
CHAPTER FOUR
111
PISTON/CYLINDER BLOCK ASSEMBLY
1. Upper compression ring
2. Lower compression ring
3. Upper oil ring
4. Spacer
5. Lower oil ring
6. Retaining ring
7. Piston
8. Connecting rod bushing
9. Connecting rod
10. Piston pin
11. O-ring
12. Locating dowel
13. Cylinder block
14. O-ring seal
Removal
112
1. Remove the cylinder head as described in this
chapter.
2. Remove all dirt and debris from the cylinder base.
3. If still in place, remove the two dowel pins and
O-rings (Figure 112) from the top of the cylinder
block.
4. Turn the crankshaft until the piston is at bottom
dead center (BDC).
NOTE
The front and rear cylinder blocks are
identical (same part number). Mark
each cylinder block so they will be re-
installed in their original positions.
113
5. Pull the cylinder straight up and off the piston and
cylinder studs. If necessary, tap around the perimeter
of the cylinder with a rubber or plastic mallet.
6. Place clean shop rags (A, Figure 113) into the
crankcase opening to prevent objects from falling
undetected into the crankcase.
7. Remove the O-ring seal (B, Figure 113) from
the locating dowel. Leave the locating dowels in
place unless they are loose.
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ENGINE
135
8. Remove the O-ring (Figure 114) from the base
114
of the cylinder.
9. Install a vinyl or rubber hose over each stud
(Figure 115). This will protect both the piston and
the studs from damage.
CAUTION
After removing the cylinder, use care
when working around the cylinder
studs to prevent bending or damaging
4
them. The slightest bend could cause
the stud to fail.
10. Repeat these steps to remove the other cylinder.
115
Inspection
To obtain an accurate cylinder bore measure-
ment, the cylinder must be torqued between torque
plates. Measurements made without the torque
plates will be inaccurate and may vary by as much
as 0.001 in. (0.025 mm). Refer this procedure to a
shop equipped and experienced with this procedure
if the tools are not available.
The torque plates (Figure 116) shown in this proce-
dure are JIMS Cylinder Torque Plates (part No. 1287).
The cylinder block bore must be thoroughly clean
to obtain accurate measurements. The cylinder
116
must be at room temperature to obtain accurate
measurements. Do not measure the cylinder imme-
diately after it has been honed, as it will still be
warm. Measurements can vary by as much as 0.002
in. (0.051 mm) if the cylinder block is not at room
temperature.
1. Thoroughly clean the outside of the cylinder.
Use a stiff brush, soap and water and clean all debris
from the cooling fins (Figure 117). If necessary, use
a piece of wood and scrape away any lodged dirt.
Clogged cooling fins can cause overheating leading
to possible engine damage.
117
2. Carefully remove all gasket residue from the top
and bottom cylinder block gasket surfaces.
3. Thoroughly clean the cylinder with solvent and
dry with compressed air. Lightly oil the cylinder
block bore to prevent rust.
4. Check the top and bottom cylinder gasket sur-
faces with a straightedge and feeler gauge (Figure
118). Replace the cylinder if warp exceeds the limit
in Table 2.
5. Check the cylinder bore (Figure 119) for scuff
marks, scratches or other damage.
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136
CHAPTER FOUR
6. Install the torque plate onto the cylinder (Figure
120) following the manufacturer’s instructions.
118
7. Measure the cylinder bore with a bore gauge or
inside micrometer (Figure 121) at the positions in-
dicated in Figure 122. Perform the first measure-
ment 0.500 in. (12.7 mm) below the top of the
cylinder (Figure 122). Do not measure areas where
the rings do not travel.
8. Measure in two axes-aligned with the piston pin
and at
90 degrees to the pin. If the taper or
out-of-round measurements exceed the service lim-
its in Table 2, bore both cylinders to the next over-
size and install oversize pistons and rings. Confirm
the accuracy of all measurements and consult with a
119
parts supplier on the availability of replacement
parts before having the cylinder serviced.
9. Remove the torque plates.
10. If the cylinders were serviced, wash each cylin-
der in hot, soapy water to remove the fine grit mate-
rial left from the boring or honing process. After
washing, run a clean white cloth through the cylin-
der bore. If the cloth shows traces of grit or oil, the
bore is not clean. Repeat until the cloth passes
through cleanly. When the bore is clean, dry with
compressed air, then lubricate with clean engine oil
to prevent the bore from rusting.
CAUTION
120
The use of hot soapy water is the only
procedure that will completely clean
the cylinder bore. Solvent and kero-
sene cannot wash fine grit out of the
cylinder crevices. Abrasive grit left in
the cylinder will cause premature en-
gine wear.
Cylinder Studs and Cylinder Head Bolts
Inspection and Cleaning
The cylinder studs and cylinder head bolts must
be in good condition and properly cleaned prior to
installing the cylinder blocks and cylinder heads.
121
Damaged or dirty studs may cause cylinder head
distortion and gasket leakage.
CAUTION
The cylinder studs, cylinder head
bolts and washers consist of hardened
material. Do not substitute these
items with a part made of a lower
grade material. If replacement is re-
quired, purchase the parts from the
manufacturer.
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ENGINE
137
1. Inspect the cylinder head bolts. Replace any that
122
are damaged.
2. Examine the cylinder studs (A, Figure 123) for
bending, looseness or damage. Replace studs as de-
scribed under Cylinder Stud Replacement in this chap-
ter. If the studs are in good condition, perform Step 3.
3. Cover both crankcase openings with shop rags
(B, Figure 123) to prevent debris from falling into
the engine.
4
4. Remove all carbon residue from the cylinder
studs and cylinder head bolts as follows:
a. Apply solvent to the cylinder stud and mating
cylinder head bolt threads and thread the bolt
onto the stud.
b. Turn the cylinder head bolt back and forth to
loosen and remove the carbon residue from
the threads. Remove the bolt from the stud.
Wipe off the residue with a shop rag moist-
ened in cleaning solvent.
c. Repeat until both thread sets are free of all
carbon residues.
d. Spray the cylinder stud and cylinder head bolt
with an aerosol parts cleaner and allow them
to dry.
e. Set the cleaned bolt aside and install it on the
same stud when installing the cylinder head.
5. Repeat Step 4 for each cylinder stud and cylinder
123
head bolt set.
Installation
NOTE
If installing a cylinder block that has
been bored oversize, the inner
lead-in angle at the base of the bore
skirt
(Figure 124) has been elimi-
nated. This lead-in angle is neces-
sary so the piston rings can safely
enter the cylinder bore. If necessary,
use a chamfering cone (JIMS part
124
No. 2078) or a hand grinder with a
fine stone and grind in a new lead-in
angle. The finished surface must be
smooth so it will not catch and
damage the piston rings during instal-
lation.
1. If removed, install the pistons and rings as de-
scribed in this chapter.
2. Remove all gasket residue and clean the cylinder
block as described under Inspection in this chapter.
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138
CHAPTER FOUR
3. Remove the vinyl or rubber hose from each stud
(A, Figure 125).
125
4. Install a new O-ring onto the base of the cylinder
block. Apply a light coat of clean engine oil to the
O-ring.
5. If removed, install the locating dowels (Figure
126) into the crankcase.
6. Install a new O-ring seal (B, Figure 113) onto
the locating dowel. Apply a light coat of clean en-
gine oil to the O-ring.
7. Turn the crankshaft until the piston is at top dead
center (TDC).
8. Lubricate the cylinder bore, piston and piston
rings liberally with clean engine oil.
126
9. Position the top compression ring gap so it is fac-
ing the intake port. Then stagger the remaining pis-
ton ring end gaps so they are 90 to 180° from the gap
of the ring above it (Figure 127).
10. Compress the piston rings with a ring compres-
sor (B, Figure 125).
NOTE
Install the cylinder in its original po-
sition as noted during removal.
11. Carefully align the cylinder (front facing for-
ward) with the cylinder studs and slide it down
127
(Figure 128) until it is over the top of the piston.
Then continue sliding the cylinder down and past
the rings (Figure 129). Remove the ring compres-
sor once the piston rings enter the cylinder bore. Re-
move the shop rag from the crankcase opening.
12. Continue to slide the cylinder down until it bot-
toms out on the crankcase.
13. Repeat to install the other cylinder.
14. Install the cylinder heads as described in this
chapter.
PISTONS AND PISTON RINGS
Refer to Figure 111.
Removal
1. Remove the cylinder as described in this chapter.
2. Cover the crankcase with clean shop rags.
3. Lightly mark the pistons with a F (front) or R
(rear) (A, Figure 130).
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ENGINE
139
128
132
Pad
Nut
Pipe
Washer
4
Threaded
rod
129
133
WARNING
130
The piston pin retaining rings may
spring out of the piston during re-
moval. Wear safety glasses when re-
moving them in Step 4.
4. Using an awl, pry the piston pin retaining rings
(Figure 131) out of the piston. Place a thumb over
the hole to help prevent the rings from flying out
during removal.
NOTE
Mark the piston pins so they can be
reinstalled into their original pis-
tons.
131
5. Support the piston and push out the piston pin
(B, Figure 130). If the piston pin is difficult to re-
move, use a piston pin removal tool (Figure 132).
6. Remove the piston from the connecting rod.
7. Remove the piston rings using a ring expander
tool (Figure 133) or spread them by hand (Figure
134) and remove them.
8. Inspect the pistons, piston pins and pistons rings
as described in this chapter.
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