Spray a little WD40 or GT85 in the grip and a little on the bars leave it for a second or two then put the grip back on leave somewhere warm like over night in the house or in the sun for about 10 Min's and fixed works every time for me.
Snail cams don't work on all frames so try a new chain but get a half link it should fix it for you or get something like a fixed chain tensioners off tartybikes that should solve your problem to.
If someone can pick me up on there way down if possible (PM me or some thing) or ill have to see what i can do but ill try and get down always wanted to ride my home town.
I ride both street and natural I'm just getting back in to trials had to take some time off due to doctor orders but ok now. I don't get to ride much natural i was in skegness the other weekend on the rocks thats where took the pictures.