Hi Vantage
Fairly straight forward to take apart, fettle (love that word) and reassemble. I think I traced my chafing noise down to the roller bar not being square at the ends, allowing the spacer washers to sit at an angle and touch the case as it rotated.
To get at the bits I removed the plastic covers from each end by unscrewing the Phillips head screws and pulling off. Using an allen key in one of the grubscrews holding the roller, undid the nylock nuts each end. This allows you to take off the flywheel discs and the notched aluminium disc. Then removed the two grubscrews in the roller and pulled out the spindle. Unscrewed the 2 allen screws holding the (LH) bearing and pulled that off.
I trued the ends of the roller in my small lathe although it could have been done with a file. The roller is not solid but is an extrusion with, I think, 4 slots going through it. Once that was done I went through the other bits to do a bit of deburring and balanced the aluminium plate. They had taken more off one side than the other. Simple filing cured that.
After the clean-up I reassembled the bits making sure the spacing washers at each end were not jammed in. The 2 plastic end caps have little locating projections to make sure they go on the right way. To do a trial assembly I used plain M8 nuts in place of the nylock nuts to make it easier to do the trial fit and when happy re-fitted the nylocks.
The more complicated end houses the circular magnets. The notched aluminium disc rotates between the magnets and works by, I think, producing an eddy current braking effect as the speed increases. It warms up a bit (as do I) when in use. The plastic end holding the outer magnet has a "ramp" which allows the magnet to be pulled outwards to change the gap when a cable is pulled. I haven't made a "shifter" yet to do this operation. Using the adjusting screw to lightly push the roller onto the wheel I am using the bike gears to increase and reduce the load produced by the braking effect. It makes me puff a bit, but I am old and need to get fitter.
Some of these exercisers seem to have the cable adjuster supplied with the unit but being a bit of a cheapskate I went for the lowest price! Not a difficult job to fettle. It may be worthwhile to tidy it up and see if the resistance increases.