Obviously it will be more pronounced when trying to kick through compression. Best to get your mate to kick it slowly through compression whilst you study what it happening. If the cush lobes are rising high up each other by more than say 2/3rds the travel, it's a good sign that either the nut is loose or the spring is wrong or weak. (Then try it with some vigor to see if they rattle over)
I have some of Robb Nortiers special sockets for the cush nut .....£22 plus Post.....Selling on his behalf if you haven't already got one. Ron

email (option): ronpier@talk21.com

with what i can see Ron it is going over 2 thirds , i will give it some vigor when kicking and get some one to see what is happening

The cush drive spring should be 1 5/8" long when new...Personally I take remedial action if the cams move more than 1/3 of their total lift when the engine is being turned over slowly using the kick start. You should find the engine will come onto compression, the cam will operate slightly and then the spring pressure will exceed the compression pressure and the engine will turn over through compression........Ian

email (option): ian@wright52.plus.com

The simple thing to do is to pull off the primary cover and watch what is happening by prefference with some one else doing the kicking
The method I use for adjusting latter model clutches ( not single spring ) is to put the front wheel against a brick wall, engage first gear , remove the spark plug lead so the engine can not start then give it a kick.
Naturally you should not be able to do this if you can then the clutch is slipping.
Or on a preunit bike the clutch or the cush drive is slipping.

If you are by yourself, a slipping clutch will be quietish, just making a whooshing sound and be sort of smooth
A slipping cush drive with go thump , thump as the lodes slide over each other and will be lumpy.

If the lobes are jumping over each other then the cush drive requires replacing.
The sprocket gets replaced regularly but the retainer does not so cumulative wear makes the lobes flat .

email (option): bsansw1@tpg.com.au

The cover is off and i have tried to see what is happening but it is very intermittent

I will have a closer look to see if i can see any wear ect on the cush drive , i have checked the nut and it is tight

Ray if it's the clutch that is slipping, then the primary chain won't be turning. Ron

email (option): ronpier@talk21.com