On Changing Cams
and lifter advice.
The procedure of changings cams is typically down without
unless there was a pre existing problem with the
lifters. I have seen this
procedure down, and know of many others who simply
received the cams and
all was well.
There are a number of reasons why your lifters
bled down and produced the
racket you heard. If your mechanic did any combination
of things he could have
easily bled them down. Which is only a temporary
problem, and usually will
correct itself after running the bike long enough
for the oil to warm up, and
circulate back through the lifters.
In the process of installing the cams, the rockers
base is removed, and the push
rods are extracted, the lifters are also removed.
Your mechanic should have bled
the lifters before re-installing them. Putting all
components back in the original
position, maintains the same valve clearance, and
an adjustment of the valves
is not necessary. The critical part of assembling
the engine to avoid lifter bleed
down is bolting the rocker base back on. Because
the Rocker base preloads the
lifters, it is important to install each rocker base
when the cylinder is at top dead
center and the cam lobes are in the fully closed
position. This way you are not
forcing the rocker base down on lifters that are
sitting on the high side of the
One final note here. The design of the hydraulic
lifters is a very basic simple
design. They rarely fail, and unless they have dirt
in them which blocks the check
valve, they are not the problem.