Hydraulic Lifters - Buell 2002 S3T Service Manual

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HYDRAULIC LIFTERS

GENERAL
See Figure 3-56. The hydraulic lifter assembly consists of a
lifter and roller. The lifter and roller, under compression force
from valve spring, follow the surface of the revolving cam. The
up-and-down motion produced is transmitted to the valve by
the push rod and rocker arm. The lifter contains a piston (or
plunger) and cylinder; it also contains a check valve, which
allows the unit to fill with engine oil, thereby reducing clear-
ance in the valve train.
When a lifter is functioning properly, the assembly operates
with minimal clearance. The unit automatically compensates
for heat expansion to maintain a no-clearance condition.
It is normal for lifters to click when engine is started after
standing for some time. Lifters have a definite leakdown rate
which permits the oil in the lifters to escape. This is neces-
sary to allow units to compensate for various expansion con-
ditions of parts and still maintain correct clearance operation.
Lifters are functioning properly if they become quiet after a
few minutes of engine operation.
REMOVAL
1. Clean all dirt from around crankcase. Blow loose parti-
cles from area with compressed air.
2. Remove the upper, middle, and lower rocker covers. See
3.5 CYLINDER HEAD. Pull each push rod upward
through top of cylinder head.
3. See Figure 3-58. Remove both push rod covers (4).
a. Remove screw (8) and washer (10).
b. Lift retainer (6) and seal (7) upward a few inches on
push rod cover (4).
c. Push upward on push rod cover while pulling bottom
of cover clear of crankcase. Remove cover.
4. Remove both hydraulic lifters (3).
a. Remove two anti-rotation screws with washers (2).
b. Remove lifters (3) from crankcase bore using a thin-
bladed screwdriver. Mark the location and orienta-
tion (front/back) of each lifter.
CLEANING AND INSPECTION
1. Clean all parts, except roller/lifter assembly, thoroughly
in solvent. Blow dry with compressed air.
NOTE
Inside and outside micrometers used for measuring lifters
and lifter guides must be calibrated to ensure accurate read-
ings.
2. Inspect hydraulic lifters for excessive clearance in guide.
Accurately measure lifter bore inner diameter with a
gauge.
a. Clearance should be within 0.0008-0.0020 in.
(0.0203-0.0508 mm).
b. Fit a new lifter and/or replace crankcases if clear-
ance exceeds SERVICE WEAR LIMIT of 0.0030 in.
(0.076 mm).
b0174x3x
Oil
Figure 3-56. Lifter Assembly (Typical)
3. Check lifter roller freeplay.
a. Roller clearance on pin should be within 0.0006-
0.0010 in. (0.0152-0.0254 mm).
b. Replace lifters if clearance exceeds SERVICE
WEAR LIMIT of 0.0015 in. (0.0381 mm).
4. Check lifter roller end clearance.
a. End clearance should be within 0.008-0.022 in.
(0.203-0.559 mm).
b. Replace lifters if clearance exceeds SERVICE
WEAR LIMIT of 0.026 in. (0.660 mm).
5. Soak lifters in clean engine oil. Keep covered until
assembly.
3.15
Piston
Oil
Check Valve
Roller
2002 Buell S3T: Engine 3-41