rattles in rockers

[1608]

Whilst investigating engine rattles I noted that the manual suggested that one cause can be end float in the rocker shafts, and glibly suggests gently heating the rocker cover and tapping the inboard bush outwards (there was 20thou play in mine). I tried this and only succeeded in bruising the stubborn bush which didn't move and made it impossible to replace the axle sleeve. Luckily a neighbour lent me a suitable reamer. I found a far easier AND SAFER cure was simply to grind the end of the axle sleeve. Has made a difference. Any reason you can't simple add a shim to do the same job? anyone any views on this.
Also, I discovered that the Exh push rod had quite a deep gouge about 4" down from the top, luckily I had a good replacement. The gouge corresponds with the narrowing neck near the top of the p/rod tube and not the top where one would expect it ( some re-pro tubes have a pronounced swaged lip which can cause this ). Having put it all back together everything looks to be safely lined up, can anyone throw any light on possible causes. I can only assume that at some time the push rod was not replaced properly in the tappet.

[saltbox alf]

Re yon pushrod, not unheard of the tappet coming loose and the rod jumping out of place, oh er missus!!
Rocker axel shafts, have you got the felt washers in place? cos they kind of take up the end float.

[1608]

Thanks Alan, I asked on 'Helpliner' and a quick and friendly response was that its quite common on the singles and is usually caused by a sticking exh valve. But, I suppose a loosening tappet would do the same. I think you've got the felt affecting end float a bit wrong though if you don't mind me saying. I imagine it acts as a slow release of oil and has a damping effect to, to prevent rattle. You need to look at an exploded view to see what I mean.

[Colin F]

Re yon pushrod, not unheard of the tappet coming loose and the rod jumping out of place, oh er missus!!

It can happen!

On way to Portugese IJR in late 90's I had the rocker box off the G3 to tighten the head bolts (had the head off a week before the rally) so was doing the final tighten in a little square in Northern Spain. Several Dutchmen came up asking about the bike/ whaat was I doing/where was I going etc. as I carried on working. I must have forgotten to turn the engine over to lift the pushrods so that I could nip the locknuts up tight.
Following morning half way up a mountain the bike spat back through the carb and died!
I started to strip the bike on the side of the road and soon found that the exhaust push rod locknut had not been tightened and had slowly unwound it's self until it fell out of place!

A quick re adjust of the tappets and was on my way with no further problems.

[saltbox alf]

quite right John help hold the oil , I was just wondering if the felts were missing or gone hard and or worn away.
Was looking at my rockers as the case is still dismounted. Was very little end play and no rock laterally in the axle.
I would think that if you still have excess end float since you replaced the bush and bits, a shim would not hurt, after all so many other shafts and axle's have shims to get the desired gap.
Perhaps in the past the axle housing in the rocker cover had been worn down a bit, hence the excess play, in conjunction with the damaged pushrod, pointing to a past mishap. Hard to tell without a comparison cover to measure, but if it is a bit worn a shim would do fine (he says repeating himself)
I have had a look at a couple of manuals and there is no diffinitive tolerence given, so I suppose if it a'int tight or flopping about in the breeze must be about right.
If what you have done has made it a lot quieter, then thats a good result.