Hydraulic Lifters - Buell 2005 FIREBOLT Service Manual

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HYDRAULIC LIFTERS

GENERAL
See Figure 3-123. The lifter assembly consists of a hydraulic
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 lifter clearance. The unit automatically compen-
sates 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. Hydraulic lifters have a definite leak-
down rate which permits the oil in the lifters to escape. This is
necessary to allow units to compensate for various expansion
conditions of parts and still maintain correct clearance opera-
tion. Lifters are functioning properly if they become quiet after
a few minutes of engine operation.
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1
1. Oil
2. Piston
3. Oil
4. Check valve
5. Roller
Figure 3-123. Lifter Assembly (Typical)
REMOVAL
1. Clean all dirt from around crankcase. Blow loose parti-
cles from area with compressed air.
2. Pull each push rod upward through top of cylinder head.
See 3.6 CYLINDER
3. Remove cylinder head assemblies. See
HEAD.
4. See Figure 3-125.
a. Remove screws.
b. Remove push rod covers.
c. Remove gaskets and o-rings. Discard parts.
5. Remove valve hydraulic lifters.
a. Remove anti-rotation screws.
b. Remove lifters from crankcase bore using a thin-
bladed screwdriver. Mark the location and orienta-
tion (front/back) of each lifter.
CLEANING AND INSPECTION
2
Compressed air can pierce the skin and flying debris
from compressed air could cause serious eye injury.
Wear safety glasses when working with compressed air.
Never use your hand to check for air leaks or to deter-
mine air flow rates. (00061a)
1. Clean all parts, except roller/lifter assembly, thoroughly in
3
solvent. Blow dry with compressed air.
Inside and outside micrometers used for measuring tappets
and tappet guides must be calibrated to ensure accurate
readings.
2. Inspect valve lifters for excessive clearance in guide.
Accurately measure lifter bore inner diameter with a
4
gauge.
a. Clearance should be within 0.0008-0.0020 in.
(0.0203-0.0508 mm).
5
b. Fit a new lifter and/or replace crankcases if clear-
ance exceeds SERVICE WEAR LIMIT of 0.0030 in.
(0.076 mm).
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.
HEAD.
3.6 CYLINDER
Remove push rod covers.
11 1
WARNING WARNING
NOTE
2005 Buell Firebolt: Engine
3.16
3-85