After a couple of mows, it's clear one of the reel bearings is squealing. Given the stethoscope and frankly simple hearing it's the non-drive side.
We pulled the reel and bearings today and both of them feel fine. They were replaced 2 years ago by the bloke who sharpened the reel and bedknife. They don't look like cheap bearings, they don't feel like cheap bearings but when spinning the reel under motor, one of them squeals. This thing has probably mowed ~20 times since they were replaced. Never seen moisture, always stored under-cover. It's weird. The bearings have standard size markers but no manufacturer details. I can only assume they were replaced with sub-par bearings.
I'm off tomorrow to my local bearing supplier to replace them with quality Japanese bearings and we'll see how we go. I might buy 4 and stick 2 on the shelf to replace in case the next sharpen has them replaced with "less than quality" units.
I'd like to get it sharpened, but my son seems hell bent on mowing without a thorough raking and we get the periodic "ting!". So I'll set it up with new bearings and that'll do for a while.