Join Date: Feb 2008
Location: Seabrook, TX, USA
Re: Just curious, why do we adjust valves?
There are plenty of bikes with hydraulic lifters (including GL1500 wings), but hydraulic lifters are inaccurate relatively speaking in terms of valve timing. Because there is oil used to cushion the lash; the timing, duration and lift of valve opening varies somewhat and is less precise than "solid" lifters. If you ever played with cars, you recall that race cams are almost all solid or roller tappet (at least they used to be). Since motorcycle engines are usually designed to extract the maximum output, the omission of hydraulic lifters avoid compromise in this area.
edit: I should have also included that hydraulic lifters are more suited for low-rpm operation. At higher engine speeds, they can "pump up" and prevent valves from closing completely which could quickly lead to a burned valve.
Life's too short to ride ugly motorcycles
Last edited by dukey33; Mar 19th, 2008 at 1:27 pm.
Reason: added info