Applying Rocker Arm Bases, A Hint or two from Dave
Written by Dave M
Thursday, 10 June 2004
Reprinted by permission from Mr Tidy's tech tips
On Changing Cams
and lifter advice.
The procedure of changing cams is typically done without changing lifters, unless there was a pre existing problem with the lifters. I have seen this procedure done, 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 cam.
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.
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This information and procedure is provided
as a courtesy and is for informational purposes only.
Neither the publishers nor the authors
accept any responsibility for the accuracy, applicability, or
suitability of this procedure. You assume all risks associated
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Any type of modification or service work on your motorcycle should
be performed by a
If performed incorrectly,
this procedure may
endanger the safety of you and others
on your motorcycle and possibly
invalidate your manufacturer’s warranty.
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Written by deeko, on 03-08-2007 10:26
My bike is sick on inspection the cam lifters are so worn that they look like someone put a thumb print in them one has actualy worn through, the cam looks a bit messed up to oil line is clear and oil pump seems to be workin wo u recken caused so much wear
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