Norton 650SS exhaust valve tip wear.

I've had several Norton twin heads go through my hands in the last few years and have noticed the same thing where the tips of the valve stems are quite indented, so I can only imagine that the valve stem tips aren't hard enough.  Maybe all the indented ones were aftermarket replacements?  Difficult to say.

Anyone have any opinions on fitting 'lash' caps to the tops of the stems?  This may though alter the rocker geometry slightly.

I've had this issue on quite a few bikes.

Some Japanese,  some British. 

I would leave as is and guess the valve clearance. (Not as hard as you might think) Or if that worried, measure it with a dial indicator. 

Don the bodger.

Owning a 650ss bitsa (Non std head) I have the noises, especially at tick over.

I have since covered 2,000 + miles with these noises. Not got any worse.

What is the prospect of long term damage as a result of this?

For what it is worth. Having observed the same wear but on the intake valve tips of my 750cc motor I swapped out the stock push rods for Commando items and installed lash caps on intake and exhaust. Besides being an easy change over the bonus is that lash caps come in various thicknesses which allows one to dial in the geometry to near perfection. The downside is a bit more top end noise.

To Mark Stockslager - Just wondering why you think there is more top end noise with lash caps fitted? I would have thought that it wouldn't make any difference. Also, you say about different lash cap thicknesses allowing you too 'dial' in the rocker geometry - but surely any lash cap is going to increase the length of the valve stem, no matter what thickness? Or are you reducing the length of the valve stems to compensate?

The factory fitted longer valves and shorter rods  to   the later  750 motors  , they were obviously unhappy with the geometry , I wonder if the  earlier 650 etc  engines  could be suspect  in that regard.

When I took our Atlas down I noticed that one of the  adjusters was beginning to break up , With the new adjuster fitted it was clear that the action was very poor.  I then realised that  someone had fitted a later longer valve . With the correct valve fitted the action was perfect . This was a real surprise  as I knew the factory  was unhappy with it  enough to make the changes. On further reflection I realised that the valve seats had sunk over the years  and  this had corrected the action !!.  As the bike was going to be used by Captain sensible  and treated like a Harley I decided to get the chamber and seats reprofiled  to suit.  It has worked fine ,  and illustrates  that  you need to expect  the unexpected with these old  clunkers.