Thrust washers on rocker shaft

marshg246 · Oct 18, 2025

Opinions, opinions, I'm out.

Stephen Hill · Oct 18, 2025

Does this mean I win?

Sorry, couldn't resist.

Stephen Hill said:
Isn't there a school of thought that says that when you shim the rockers to get the correct amount of offset (or offcenter) to ensure the valves rotate, the valves don't rotate anyway?

Britbike850 · Oct 18, 2025

Well, I’m about to give up on replacing the valve seals without removing the head….lining up the 12mm temporary rocker shaft has become a joke….finally get the temporary shaft thru the thrust washers into the rocker arm…spent 2 hours trying to get the spring washer…playing with needlenose, hemostats, tweezer, and magnets in place…with the pushrod engaged…takes a surgeon hands and more patience than I have…after 2 days of frustration… I think I’m going to pull the head…haven’t started the other intake seal

…this is way worse the replacing the horn
Rod

BERT · Oct 18, 2025

Triton Thrasher said:
Although that’s not the same as it actually happening.

True

BERT · Oct 18, 2025

Carl H said:
I edited my post to say " One straight line scratch." or Wear mark. I do my own valve jobs as I want to do as much as I can to get better flow from the seat area and also fit the stem to guide clearance as Precision Machining recommends with their " Black Diamond" product line. For me it is a labor intensive job to do race quality top ends that hold up for years. It is easier if you do the disassemble yourself and make notes on what you need to correct with a few minor adjustments.

Think of what the wear mark would look like if a valve tip that rotated with an off-center rocker arm adjuster.

There shouldn't be if the geometry is correct. The softer material between the two would evid. Offsetting the centerline axis of the rocker arm up and down motion a wee bit with the centerline of the valve stem axis perhaps would cause the valve to rotate a smidgen as it might have been designed to do

ludwig · Oct 18, 2025

I find it very unlikely that the factory paid great attention on assembly to where precisely the rocker hits the valve. If so, they would have mentioned it in the workshop manual.
Maybe some rockers hit dead centre, some slightly off.
Not 'designed', but hit and miss. Typical of their sloppy engineering.

baz · Oct 18, 2025

not a Norton but interesting

Thrust washers on rocker shaft

marshg246

Stephen Hill

Britbike850

BERT

BERT

ludwig

baz

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