Rocker shafts

[Ozmadman]

Whilst I have the top end stripped down for a spark plug hole re-thread I thought I would give it all a good once over whilst waiting for a few bits. I noticed that the rocker shafts were not smooth in their operation, no play just a bit rough. I took the shafts apart and discovered another piece of weird lightweight engineering which has also prompted a question that hopefully someone can answer.

In the each end of the rocker housing (where the shaft goes through)there are two nice thick bronze bushes with oil grooves in them(just dealing with one side here) with a space between them in the centre. I have squirted carb cleaner through the various drilling's in the cover to clean them out and to see where they go and found that I get a nice exit of cleaner from a drilling in the space between the two bronze bushes. You would think that the rocker shaft would run in these bushes and be lubricated by the nice jet of oil BUT NO!..the rocker shaft is of much smaller diameter so inserted into the nice bronze bushes to take up the size difference between the shaft and the bronze bushes is a piece of steel tubing which runs the full length and with no oil drilling in it at all and then the rocker shaft runs in that??!!! which is a bit strange as this blocks off the oil feed to the rocker shaft itself whilst allowing oil between it and the bronze bushes which is a waste of time as this tube doesn't rotate(borne out by the oil way stain marks on the outside of the tube) To add to that, according to my parts book I should have 2 felt washers part number 012722(4 for both rockers shafts) sealing off the inner ends of the bronze bushes before the inner steel tubing goes through which again seems a pointless exercise, surely you would need as much oil there as possible?? (the later models seem to have another kind of sleeve that fits between the two bronze bushes (042096). The thing is, I have neither nor is there any trace of them ever being there and it wasn't until I had put it all back together I realised(by checking the parts book) that they were missing. I have included the only picture I can find of the set up showing the later(042096) so you can get an understanding of what I have tried to explain but there is no mention of this or dismantling of the rocker gear in the workshop manual. Just to clarify the bushes (017103) are the bronze ones with the oil ways in.. the tube (042076) has no oil drilling's in it and the rocker shaft is free to rotate in the tube.. What I am now wondering after writing all of this is whether the steel tube should be clamped tight on the shaft when tightening up the ends and the whole lot should be running in the bronze bushes(after all you don't normally run a steel pin in a steel bush do you?? if so then the bronze bushes will need to be tapped into the casing a tad to allow the steel tube to exit a fraction for this to work???? anyone???

Thanks Paul

[SPRIDDLER]

Hi Paul.
Your question is not something which has arisen when I've been re-asembling a rocker box. However, in order to alleviate the boredom of chomping on my muesli I've given it some high fibre thought.....

If I understand the situation your assumption is corrrect: Since the rocker arms (pushrod end and valve end) are a sliding fit on their splines there needs to be a way of ensuring that they are spaced the correct distance apart and acting directly over the pushrod cup and the top of the valve stem, even though the pushrod (but not the valve stem) is able to move to align itself with the rocker arm.
Assuming this to be the case could it be that the steel sleeve for rocker axle is the correct length to achieve the correct spacing between the two rocker arms?
Thus, the rocker arms are slid onto the splines and then the washers and nuts are tightened, drawing the rocker arms hard up against the ends of the steel sleeve which will then move with the rocker axle within the bushes.

(The bushes are normally tapped in or out to take up the end float of the rocker axle to prevent a 'clacking' noise from the rocker box).




Chomp, chomp, chomp, chomp...........

[1608]

Good luck with replacing the felt washers too, they can be awkward to say the least.

[Ozmadman]

Morning Neville

Yes it seems so! last night after writing about it, even though it was late, I decided to dismantle the rocker box again in my kitchen (Where I do all my work actually!! no garage you see) and I assembled the shaft, ends, tube etc outside of the rocker cover and the ends do indeed clamp the tube which will then allow it to rotate as as unit within the bronze bushes, so that seems to sort the issue, apart from the fact that when tightened all up within the cover the rocker action is a bit tight, could probably be relieved by a few rubs of an oil stone on the ends of the bronze bushes.(don't want to try tapping them in as they may go a bit far and be impossible to tap out again) I did order 2 new sleeves from the club but have just had a phone call, whilst writing this, from Louise at club spares, to say the sleeves are out of stock, drat, mine are a bit rough where it looks like they may have been seized/rusted at some point.... and what do you think about the felt washers should I fit them do you think as they would appear to seal off the ends of the bronze bushes and restrict the oil flow between bushes and sleeve.. enjoy your muesli, I am about to have mine and it's sunny here and the bike is in bits!!!

Paul

[Ozmadman]

Good luck with replacing the felt washers too, they can be awkward to say the least.

Yes I wondered about that, look a bit of a pig

Paul

[SPRIDDLER]

Paul. The felts aren't actually seals but oil reservoirs or 'wicks'.
I found it quite impossible to fit the felts on my 350 H/W some 15,000 miles ago (patience is not one of my many attributes) so, ahem, I left them out No discernable problem so far in spite of some very long European camping trips (e.g. Milan, Spain) and a couple of virtually non-stop 400 miles runs in a day so plenty of opportunity for the bushes to overheat/wear/seize etc.
The bushes are a fiddle to adjust. I use a piece of threaded rod and washers to pull them inwards but moving them outwards is a strugglee for which I've no clever solution. Some sort of spreader is called for. Maybe someone will offer a simple solution. I wish you patience and good luck with the oilstone though.

I've been down the shed (fully dressed now, to spare my Neighbourhood Watch team any unwelcome exposure to my 'Mr Men' pyjamas) to look at a couple of spare rocker boxes and refresh my memory. To move the bushes outwards I seem to remember using a threaded rod with a washer on the 'inside' which contacts the bush, and a collar on the 'outside' having a larger i.d. than the bush o.d. but there's not much room and it's a real fiddle as you have to re-assemble the axle, rocker arms etc. each time to check the clearance/end float.

To save the oilstone marathon I suppose you could just disassemble the axle and fit a thin washer having a greater i.d. than the steel sleeve before fitting the rocker arm and then reassemble, tightening the nuts on the ends of the axle, which would force the bushes inwards until the rocker arms are hard up against the steel sleeve. Then remove the washers so that upon re-assembly there will be a clearance between the rocker arm and the bush the same size as the thickness of the washer.

Other bodges are available.

[Ozmadman]

Thanks I will review those options, just need to find 2 new sleeves now!!

Paul

[SPRIDDLER]

Ah, I rambled on about the one piece steel sleeve assuming you already had the one piece sleeves.

[Ozmadman]

Ah, I rambled on about the one piece steel sleeve assuming you already had the one piece sleeves.

no worries I do have one piece sleeves just need two new ones, one for each side! as mine are past their best


paul

[Ozmadman]

Good luck with replacing the felt washers too, they can be awkward to say the least.

+

Paul. The felts aren't actually seals but oil reservoirs or 'wicks'.
I found it quite impossible to fit the felts on my 350 H/W some 15,000 miles ago (patience is not one of my many attributes) so, ahem, I left them out No discernable problem so far

Got my new rocker sleeves, assembled it all to check that it all ran free with no play and it did, then dismantled it all to fit the dreaded felt seals (2 each side that go in the space between the bronze bushes. What clown designed such an abortion? So do I leave them out or not? to me it seems they may actually restrict oil flow to the bushes but as they are supposed to be there then give it a go I thought( my other hobby is working on old clock movements so I am quite patient, well most times) . Fiddly? yes.. damn annoying and frustrating?yes.. impossible? no. It took me about 90 minutes of patient poking with a toothbush handle and using both little fingers to squash the oil soaked felts(mine just about fit into the bronze bush) to finally get them in place and fit the sleeve into the bronze bushes.

Paul