buell s1 lightning '97 Manual

See 

 The tappet assembly consists of tappet and

roller. The tappet 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 tappet 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 tappet is functioning properly, the assembly operates
with minimal tappet clearance. The unit automatically com-
pensates for heat expansion to maintain a no-clearance
condition.

It is normal for tappets to click when engine is started after
standing for some time. Tappets have a definite leakdown rate
which permits the oil in the tappets to escape. This is neces-
sary to allow units to compensate for various expansion con-
ditions of parts and still maintain correct clearance operation.
Tappets are functioning properly if they become quiet after a
few minutes of engine operation.

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

. Pull the

push rod upward through top of cylinder head.

3.

 Remove screw (11) and washer (13). Lift

retainer (9) and seal (8) upward a few inches on push rod
cover (7). Push upward on push rod cover while pulling
bottom of cover (7) clear of crankcase. Remove cover (7).

4.

Remove screw (5), washer (14), and plate (4). Pull O-
rings (3) off ends of pins (2) and discard. Grasp ends of
pins (2) and pull outward free of crankcase. A pliers is a
handy tool to free pins (2). With a thin-bladed screwdriver
in the retainer groove at the top of the tappet, pry upward
on the tappet until it extends above the gearcase and can
be pulled out by hand.

1.

Clean all parts, except roller/tappet assembly, thoroughly
in solvent. Blow dry with compressed air.

2.

Inspect valve tappets for excessive clearance in guide.
Clearance should be 0.0008-0.0020 in. (0.020-0.051 mm).
Accurately measure tappet bore inner diameter with a
gauge. Service wear limit is 0.0030 in. (0.076 mm).
Excessive tappet guide clearance is corrected by fitting a
new tappet and/or replacing crankcases.

NOTE

Inside and outside micrometers used for measuring tappets
and tappet guides must be calibrated to ensure accurate
readings.

3.

Check tappet roller freeplay. Roller clearance on pin
should be within 0.0006-0.0010 in. (0.015-0.025 mm).
Recommended service practice is tappet replacement.
Service wear limit is 0.0015 in. (0.038 mm).

4.

Check tappet roller end clearance. Clearance should be
0.008-0.022 in. (0.203-0.559 mm). Service wear limit is
0.026 in. (0.660 mm).

5.

Tappets should be soaked in clean engine oil and kept
covered until assembly.

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