Yeah, I don't know that I agree with the statement either. In over 52 year of riding and owning about 25 different motorcycles, that has not been my experience. I've had , lets see, 4 Hondas, 4 Yamahas, 5 Kawasakis, and 3 Suzukis. The rest were a BSA, a Bultaco, a Royal Enfield, and 2 Harleys. I'm forgetting a few here, but yoy get the picture. Of the Japanese bikes, I really have to believe that the quality of them all was pretty equal. The one Japanese bike that blew up the engine was a 2001 Kawasaki KLR250. That wasn't due to any design flaw. Just a dummy in the production line that hadn't learned, that with a silicone sealer, you can't go by "if a little is good, a lot must be better". My bikes have all been either street bikes or dual sports. I think, going way back, the very early Suzukis may have had a reputation of being slightly tacky in the detailing. But my Suzukis have been excelaant motorcycles, and I wouldn't hesitate to buy a brand new DR200, DR650, DRZ400S, S40, or a C50, or TU250 without any worries.

My only problems with Japanese designed motorcycles are, for instance, I still don't like that they all quite using replaceable bearings on the camshafts. Harley uses replaceable bearings there. Hyosung even uses replaceable bearings on the cams. Also, the dissapearance of allmost all center stands and kick starters I lament. But, I'm an old geezer, and younger riders don't seem to care about these issues.

But, in real life, almost any particular motorcycle has one or more weaknesses. They will certainly vary in the severity of those issues.

There is an issue, for example, with the Honda XR650L. There has been a number of countershafts wearing out prematurely apparently due to the fir of the countershaft sprockets to the shaft. Some owners have switched over to using the sprocket from the XR650R, and turning it over. Some buyers of used bikes have found that the previous owner, rather than splitting the cases and replaceing the worn out coun tershafts, had welded the sprocket in place when the splines wore out. If you don't believe me, go to advrider.com, get into the huge Honda XR650L thread, and search, or ask.