Honda-SOHC

You dont ever use the slot anyway, when building before fitting cam stick fingers down tunnel, push slipper to carbs and hold whilst nipping up locknut then just undo when built and holding pressure on kickstart, nipping up whilst holding pressure.

Check the tensioner fold over tabs are crimped over tight to hold theteeth on the bolt in mesh with the rack, people forcing the screw slot in the false idea that this will tension the chain is what damages the meshing in the first place

With the drive gear of course!

Not normaly that tight a fit if routed right

The washers stick in the head recesses but if really missing are still available new.
On the adjuster is the thread stripped all the way down or just at the end? Honda should never have put that slot in there it gets abused.
New pattern ones are available but expensive and dont often come up used in good order any more.
I MAY have a used one but it wont be cheap

The early K's had some problems but they were inline 3 or 4 cylinder bikes, i was taught by a good bm mechanic how to stop tappet rattle and will pass that on if you wish

Trouble with the Haynes Ash it tries to cover the 350,400,500 and 550 the smaller ones are different enough to make that cnfusing rading.
I was told that Haynes had bought Clymer but not sure how true that is, their museum is worth a visit

Bike or manual? The parts book on there is Japanese.
I supplied them all to Ash by the way.

I can still burn the all to a dvd for a small fee if wanted

Alladins cave on here but you need the 500 manual plus the supplementsup to your model