While replacing the chain and sprockets I noticed that the rear axle has a bit of play, so I decided to replace the bearings too. While waiting for the replacement parts to arrive I had it taken apart. Fast forward about 2 months and ready to put it back together, but I noticed an issue when tightening the rear axle nut. Since some time has passed, I already forgot how hard it was on, but I found some other discussions about the proper torque being around 200nm. Since it's unlikely I have that much strength to hand tighten the nut, I suspect something is wrong because I do not have to tighten the nut very hard at all to make the axle to seize up completely. Have I put it back together incorrectly or forgot some part, or does the axle loosen up if I tighten the nut past some point? It feels wrong so I thought I'd better ask before I completely destroy it by overtightening.
Yep that doesn't sound correct to me. I'd suggest that something is indeed wrong. Check the fitment off CMNSL spec sheets if you are not using a manual.
Found the problem. One of the washers/spacers had gotten stuck in some grease inside the chain tensioner, probably when I was figuring out how everytihing goes back together. I moved the spacer to the correct spot on the other side of the bearing it was stuck on and now everything works perfectly.