Something I learnt along time ago is chain tight spots is a misnomer. When the chain gets tight in its revolution, its because the rear sprocket is oscillating. I had this once before where it was enough to cause concern, but its something I've not normally worried about and chain adjustment has been fine when the adjustment allows for it.
On this bike the difference in chain tension when you rotate the wheel is alarming! So I have loosened off the sprocket nuts, turned the wheel until the chain slack is tightest, then tapped the rear sprocket towards the front. I couldn't really see it move, but I know have an even but over slack chain all round!
I expect many of you know about this, but thought i'd mention it in case you didn't. I can't see a make on the sprocket, but will check the s/history to see if its in there and named? I'll adjust it properly now and see how things are in a couple of mikes. Any movement and i'll fit a OEM one, but last time I did this, it sorted the problem permanently.
Speaking of adjusting the chain: Like most of us I never know what to ask for on birthdays or at Xmas, but one year my love of gadgets lead me to ask for a tru tension chain monkey. It grips the sprocket and shines a laser dot up the chain line so you can see if things are in line. Anyway, it was unwrapped and then found its way unused to the loft. I just found it up there and thought as I'm doing what I'm doing I'll give that a go. Not that i need it of course, been working on bikes for years and I certainly know how to align a rear wheel ffs!
Might even just buy a OEM one?
