commando rocker spindle remover

It'll help if you can run the engine first, so the head's pretty much at riding temperature â at that temperature I can pull my rocker spindles out without any special tool, certainly with just a bolt threaded in and a pair of pliers to pull with. If the head's off and there's no-one to stop you, stick it in the oven for a bit. The right tool is always best though, and I'd recommend this over a slide hammer, for this job, with the head removed from the engine: http://www.mca-aston.co.uk//parts/search/P189

No problem, I'm sure I was just the first of very many who might've answered â that, and I happened to pull out a couple of spindles only last weekend so it's very fresh in my mind! Apparently 'The extractor bolt/stud size needed is 5/16" Cycle (26 tpi) thread', per the second post here: https://www.accessnorton.com/NortonCommando/rocker-shaft-removal.1825/ â I wish I had a workshop, let alone a lathe! Good luck with it, once the covering/locating plates are off there's nothing holding the spindles in place but interference with the head, which the heat will reduce or even eliminate. I'm sure someone'll correct me if I'm wrong, but I went through this removing bearings from the gearbox last summer â heat eases the interference because the ally of the head expands more at a given raised temperature than the steel of the spindles; and I'd be very afraid of trying to remove the spindles cold, as it would probably diminish the working interference for the future. Just for the avoidance of doubt, you may well know more about that than I!

I too have done this recently; I *don't* agree that the task should require significant effort.

My beloved partner is most supportive of my bike habit, but would be *very* unhappy if I went about putting cylinder heads in the oven.

Luckily a few minutes with an electric hot-air gun was sufficient to get the head warm enough for the spindles to come out with little effort from the slide hammer -- and ditto for the actually more demanding task of reinserting them such that their end slots are correctly aligned.

Previously Allen Hanford wrote:

Thanks for getting back to me. Sounds like it's okay if removal takes some effort.

The head is off the bike. Do you know what thread the inside of the spindle is? I was using UNF which I know isn't right but I didn't have a British bolt that fit. If I can find out what the thread is I can make a puller on the lathe in a few minutes.

BTW my wife is out of town for a few days so I can use the oven any way I please

Regarding the spindle internal threads - I can't find the reference at the moment but I'm sure I've read that on the Dommie there are some frame bolts with the same thread. So you might also have the correct 5/16 cycle thread somewhere on the Commando? Maybe holding a Z-plate,or seat you could take out temporarily.

Also the spindle should be replace the right way up.

Yes, I hope what I wrote indicated that there should be no great effort in removing the spindles, barely any, in fact, when done correctly; and yes, the flats on the spindles towards the valves.

Interesting â maybe so! Searching Google I found tuning notes from RGM that touch on this, and suggest how to clean up the spindles â I'd be interested in the state of the bores in the rockers too: https://www.rgmnorton.co.uk/csi/1245184/f/pdf/750_tuning_notes.pdf

I expect that the bores in the head for the rocker spindles will have suffered a bit as the spindles were extracted â those audible 'clicks' â but I'd be hopeful that no great harm has been done, perhaps depending on how much metal the spindles had picked up, especially circumferentially. However I've never encountered this problem and, to be honest, my experience is going to be very limited compared to that of many others on the forum, I'm sure. Anyway I hope that's of some help.

Do you have a lathe and an accurate enough micrometer to make a go/no-go gauge before replacing the rockers? The alloy bore in the head is surely more likely to be at fault than the rocker spindles. Some caustic soda (with care...) should clean alloy off steel rockers (obviously don't let the evil stuff anywhere near any bike alloy!!)

Next question of course is to try and find out what size and tolerance the bores in the head should be and indeed if the rocker shafts were correct in the first place...