RE: [T TBS R] Valve Clearances
Good answer. Thanks.
From: mickmaguire66 [mailto:mick_s_maguire@...]
Sent: Tuesday, August 06, 2002 7:04 PM
Subject: Re: [T TBS R] Valve Clearances
for direct acting cams the use of shims to take up the clearance
rather than some sort of dial in adjuster comes purely down to cost.
sure you can use a hydraulic lifter as well, but again these are
expensive. In pushrod engines it didnt cost very mch to add some
adjustment into the tappets, but adjustable bucket tappets require
much more high tech. the reason that the cams are direct acting is
that you gain much more stable, precise valve timing so can gain
better performance from the engine. For mechanics doing it on a
regular basis valve shimming is no big deal, the key is to have a
good supply of all sizes of shim.
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- There is a slight loss in power using hydraulic self-adjusters. Not
entirely sure why, anyone else know?
--- In triumphthunderbirdsportriders@y..., "Niles Reichardt"
> This brings up a philosophical question that I have pondered forsome time; but never bothered to bring up. What is the mechanical
advantage of adjusting valves with shims?? I've got to admit I kinda
think it may be taking the "proven technology" idea a bit too far. I
guess I can see that self-adjusting valves could self-screw up. Does
this just add more of that English character to the bike or what??
> -----Original Message-----
> From: macboots [mailto:no_reply@y...]
> Sent: Monday, August 05, 2002 6:39 PM
> To: triumphthunderbirdsportriders@y...
> Subject: [T TBS R] Valve Clearances
> Just did my first valve clearance check at 9k miles...
> Two inlet valves were 0.05mm and one exhaust was 0.12mm. All
> were in spec.clearances
> I've never heard of anyone else finding out of spec valve
> on the first check, and 0.05 mm on an inlet sounds pretty grossout
> (0.1mm-0.15mm is the spec). Naturally I'm going to get some shimschecked
> (and the tool), but I wonder if I did something wrong when I
> them... (wouldn't be the first time, I know how to turn a wrench,but
> am no mechanical prodigy)but
> I rotated each set of cams until they were pointing away from the
> cylinders, just like the shop manuals says, and then measured the
> gap. One inlet was actually 0.03mm the first time I measured it,
> after rotating the bucket holding the shim in place it came up tolazy
> Anyone else have a similiar experience? Perhaps they were just
> the day they put my bike together?http://docs.yahoo.com/info/terms/
> - Will
> '99 TBS
> '88 Jaguar XJS Convertible
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- Since there's what amounts to a fluid coupling in the valve train,
the valve timing isn't as precise as the solid mechanical linkage.
Explained better in the previous post by Mick.
Mike Stenger '98 TBS
--- In triumphthunderbirdsportriders@y..., macboots <no_reply@y...>
> There is a slight loss in power using hydraulic self-adjusters.Not
> entirely sure why, anyone else know?