This is my first experience with cassette hubs, and I'm having some derailleur travel issues. The derailleur doesn't seem to want to move far enough in to engage the largest cogs on cassette. The limit screw is set all the way out. I'm certain that its the derailleur, not the shifter, because I moved it by hand before installing the cable and it still wouldn't reach.

The cassette is 8 speed and sits very close to the spokes, leaving a sizable gap between the smallest cog and the stays. Do I just need to move the cassette farther right? Are there spacers for this, or does the wheel need to be redished?

Shifting is friction with a Suntour barcon and derailleur is a Suntour Arx long cage. Thanks in advance.

It looks to me like you need a 4.5 mm spacer behind the cassette. They are necessary when using a 7 speed cassette on a 9 speed wheel, so they're easy to find. Is the tire centered in the stays?

I didn't know this was a thing, but that seems like it will solve my problem. Thanks. The wheel looks dead center in the stays and cantilevers.

Sorry; I do not believe that the spacer will work - the cassette lock ring will not engage the hub.

You need to reposition the axle in the hub, so that the cogs are closer to the frame (chain should clear by about 1mm (.040")), which will require shifting or changing the spacers on the axle. This will allow the RD to reach more cogs, it still might not be able to reach all of them. And the wheel should be re-dished.

8+ cassettes are wider than 7- freewheels and do require more RD travel. Some older systems just don't have the cable pull to make it. Or it's possible your RD doesn't have the throw to get all the way to the bottom cog. I don't know about your Suntour stuff specifically, but for instance an NR shifter has a pretty small barrel and a NR RD has a pretty high ratio to match, so if you hook up a NR shifter to a modern Shimano RD you might have trouble getting it to move far enough. I have this problem on my Super Sport which has a Shimano RD and a shifter that was made to go with a Huret. I have juuuuust enough cable to shift it over 6 speeds. With an 8-speed cassette I'd have to give up on the outer gear.

I agree with nfmisso on this issue.

The hub was assembled wrong at some point.

Visibly, with the 8s cassette shown, there should be only 3.5mm or so between the outer (i.e. driveside) face of the smallest cog and the inner (i.e. non-driveside) face of the dropout. It looks like a few millimeters of spacer washers has perhaps been added to the driveside locknut/spacer stack, or perhaps that a substitute cone with a much greater "length" was substituted at some point.

If the driveside axle locknut has an integral spacer, as it somewhat appears to have, then substituting a regular flat locknut may fix the driveside spacing.
The overall axle spacing will also then possibly need to be restored to 130mm by tinkering with the non-driveside locknut/spacer stack, and the axle then centered so as to protrude 4.5mm or so, equally, on both ends.

I bet good ol' ARx can swing it, though. Redo your spacers so the hub shifts to the right a bit; see if the RD can cover the spread, then decide if you need to re-dish.

Deviating from the topic here, but interestingly enough, using stock shifters/derailers on my own '71 Supersport, I also have juuuuust enough cable pull from the lever to move the travel-modified "Allvit" derailer across a standard-spaced 6-speed freewheel.

This works out well, given that the Scwhinn-Approved "Allvit" has a fine barrel adjuster to keep cable tension at optimum, and conveniently serves to protect the cabling from any ham-fisted slam into the largest cog.

But in case anyone is now wondering, an Allvit won't substitute for a Shimano indexing derailer, since the actuation ratio is non-linear (i.e. highly regressive).

The cassette is way too far inboard. The lockring should be as close as possible to the right dropout,with typical clearance being in the 1-2mm range, so the chain on the first sprocket just clears with similar 1-2mm clearance.

There must be some unnecessary spacers on the right end of the axle which will need to come off. When finished spacing the rear axle, you'll also need to recheck the wheel dish.

Well there goes my Shimergeaux plans :-D