Does this chain need replacing?

Originally Posted by Red Herring

Or may only need adjusting?

If it's stretched along it's length between links then no amount of adjusting will take it out. The chain can be as tight as a drum along the run but it can still lift off the back of the sprocket.
The pitch (the distance between two links) is fixed as the sprocket pitch cannot change so if there is and appreciable stretch then it will allow you to lift it clear of the sprocket and you'll know it's toast!

[Red Herring]

The play you are describing is also an indication of worn sprockets and it's easier to describe as an ability to rattle the chain halfway around the sprocket rather than trying to lift it off. I'm sorry if I appeared a little difficult there Exuptoy, I had a pretty good idea of what you were trying to say (although I'm still mystified as to how the weight comes into it) it's just it wasn't that obvious, but as you're new on here I should have been easier on you...... Welcome aboard by the way........

No problem fella.

I have copied the section from the manual that I was referring to. I don't have an SV one so can't comment but mentioned it as it is the official way to check for wear on a Triumph. Don't worry about being easy on me fella, I'm a big boy but I have been riding for over 25 years so I do know my way around a bike.
I understand that there are plenty of keyboard warriors on the net and you don't know me from Adam but I'm not out to ruffle feathers, just to impart some knowledge to assist someone who may not have known about it. I don't pretend to know it all but if I can help I will.
Thanks for the welcome.

[Red Herring]

Well that's certainly an interesting way of assessing a chain, and the first time I've seen it, thanks.

[Red ones]

A chain is a chain. The Triumph manual is the same as the Suzuki manual and probably any other manual on the chain wear advise.

Below is the extract from the SV manual on chain wear.

[Blapper]

Tip: Make a steel gauge with points at 319.4 then measure the chain by putting the bike in first gear and pulling it back to stretch the lower run. Pulling the clutch in and moving the bike back will enable measuring at various points. When the points go into the rivets, it's time to change the chain.