yes sorry

That's might be why its riding on the roller all the time. Do you need the preload that high to get the right sag at the rear? Is there any suspension sag at all to speak of?

Worth checking your chain tension is within limits too? That can have a big effect on roller wear. If its too loose it'll drag all the time (but not put any pressure on the roller), but if its too tight when it makes contact with the roller the chain's tension can cause damage to it.

there is 40>>50mm slack in the chain i get a whine noise when riding with the plastic roller so can only assume chain is always in contact with roller. the pre load was fully adjusted when i got the bike so never touched it

The roller's job is to effectively "catch" the chain only when the swingarm is it its lowest point (shock fully extended). Sounds to me like you're riding the bike with so much preload for your weight that the suspension has little sag and is at full extension, making the lower run of the chain catch the roller. With more suspension sag (when you sit on the bike) the chain will move further away from the lower roller and nearer to the upper one. I'd try backing off the preload and seeing what happens. You want to aim for sag of about 25% - 30% of your suspension travel at the rear when you sit on the bike. Not sure what it is on the XTX, but I'd guess about 200mm? Which means you want 60-70mm of rider sag.

oh well when i sit on the bike lol it hardly moves i mean suspension dont go down much as i only weight 12st lol so mabe i should back off on the pre load

I think you've found your problem - too much preload/no sag. That'll be what's wasting your lower chain rollers.

Just to give you an idea of preload settings, I'm nearly 13st in riding gear and on the XTZ I'd have preload set about half way 4 or 5 out of 9 steps, so I'd start somewhere around there. Find a mate with a tape measure and get the sag set up properly - there's plenty out on the web about setting sag including videos on You Tube, have a search.

excellent i will try that great info i have ordered the rollers as mention on this post as the plastic were noisy so when they come will give it a go. thanks for ur help

No probs. Good luck and report back.