Quote Originally Posted by hotdog
[quote author=alanTDM link=1214322222/0#2 date=1216681922]As the shims wear then the gap gets narrower so infact it tightens up which in extreme cases if left to long you end up with burnt valves cause they are not sealing properly.
I keep thinking about this statement since I read it last night and I'm struggling to understand it. If the shims sit on top of buckets which sit on top of the valves and are directly under the cam shaft as they would be in any OHC engine... then as they wear the gap between the cam and the shim is going to get wider/bigger.

What am I missing?

Thanks,[/quote]
Your right about that i miss read the second post that would be the case they would widen, if the shims were underneath the buckets then it would tighten up I dont know how long he has had the bike but at 18k i would not of thought they would need doing yet for at least another 10k usually there checked at say a first service and if they have to have new shims not all but some its done then till the next major service eg 28k then every 28k depending on manufacture.If he has got to take it to a dealer to be done every 28k or whatever it will cost a lot in labour(fairing and watercoolant taken out etc) I done my own and the Yammy ones are about £2.50 each so not sure about Honda ones.The cost of dealer doing my TDM was £140 but have known peeps to pay £200 for shims to be replaced its the labour charges that hit your pocket.
If the camchain is on the outer side of engine and not in the middle he could use a big screwdriver to listen to it to see if it is rattling by placing next to ear and other end on casing so it acts as a stethoscope
But it just still could be the tensioner/camchain