Yep, that's exactly the same degree of play and in the same place that caused my MOT advisory, and caused the need for further investigation.

BTW, the shimming is working, currently no play at all. Incidentally the same MOT tester did my bike this October and remembered the advisory after looking at the sheet and remarked on the snug fitting linkage. I told him I had just cleaned and re-greased everything; apart from the additon of .40mm shims everything was exactly the same as the previous year. His reply was, "we get a lot of Yamahas doing this, never so much the other Jap makes."

You will not see any lateral play because the dog bones are clamped tight up against their respective collars (sleeves) forming an oblong (four defined right angles) and that, together with the bottom shock mount and swingarm pivots clamped up, effectively locks everything in place.

The up down movement you see is caused by the fact that the frame mount collar (sleeve) does not get clamped tightly at each end due to the fraction of a millimetre of end float. Without the ends of the collar being nipped up tight, together with the fact the through bolt is a smaller diameter than the bore of the collar, means that the collar can move up and down a millimetre or so. Even the slightest bit of slop here causes a considerable amount of movement at the wheel due to the magnification effect of the linkage ratio.

What I found if that, because the collar is effectively loose, the bearing at each end wasn't doing anything, the collar was receiving all the load and bearing (moving) on the through bolt. I could clearly see the wear on the bolt from the collar rotating on it which further added to the vertical play in the linkage.

As a side note, I had to replace the collar and bolt because of wear, but not the bearings as they were fine as they'd seen little use. Since fitting the shims nearly two years ago the play has not returned and has not been mentioned again by the MOT tester.

If you have slop in the frame linkage pivot, then the only cure is to fit shims, or get a slightly longer collar machined up (which is what I shall be doing next time I strip the linkage).

BTW I removed all the MPL solid lubricant carrier from the bearings in the linkage and swingarm about four years ago and replaced with waterproof marine grease. The last time I had it all apart everything looked mint. You cannot re-grease MPL bearings contrary to what the service schedule says (there's no room for any), you can only grease the collar. They are full compliment bearings so you can lose the MPL even from new bearings. It is not a cage as such; it's just there to aid assembly and slowly bleed oil into the bearing rollers over time, and this is the problem, the MPL runs out of oil to bleed out and it cannot be replenished (unless you fit a new MPL bearing). Grease (which is just a liquid carrier for the lubricating oil) can be replaced.

Glad you did bring this up again Pepsi, I noticed some slop in my linkage a little while back when raising the rear of the bike up to full extension. With riding on corrugated dirt roads it probably wouldn't take long to wreck the bearings. Mines up for its next service in Oct/Nov & will still be under warranty so I had it in mind to point it out to the Dealer then.
Re-reading this thread by Pleiades it now makes more sense to me having the same issue. With all the Automotive & Industrial suppliers around here I shouldn't have to much trouble finding the required shims if need be. Cheers.

Be wary that the physical condition of the solid MPL bears no relationship to whether the suspended oils within it are present or not. You can have mint looking MPL needle rollers that have no lubricating power left at all as they have given up all their oil.

Glad you've got it all sorted. :023: