My new Genuine Norton valves, had troughs worn through the valve tips after only 3000 miles. Even after I perfected the pushrod lengths, with new valve seats, I could still see the tappet adjusters slide from one side of the tip to the other.
So I removed the head and valve springs and operated the valve opening with my hands to see what the problem was.I discovered that if I held the valve 80 thou away from the seats, and screwed the adjusters in 80 thou to maintain the same valve clearances, the adjusters no longer slid across the tips, they stayed in the same contact point on the valve tip, and simply leaned over as they opened the valve.
So I had 180 thou machined off the tips, 100 thou for the thickness of the lash caps I fitted. (Do ensure your lash cap bottoms do not contact the valve spring collet keepers).
Been around 20 years since I did this, the valves never need adjusting, instead of a great gauge worn across the tips, I now have a ting circle in the centra of the lash caps where the adjuster makes contact in that one point.
So I thought I would film it, though see the part I wanted to show disappears from view as the valve opens, but maybe you will get an idea.
My guess is that camshaft lift is wasted in movement across the valve tips, with mine, all lift is used to open the valves.
9 июн 2024
