1958 G9 Engine sprocket troubles

Simonn · Post by **Simonn** » Sat Jan 20, 2007 8:04 pm

I need to get the primary chaincase off and am having trouble getting the engine sprocket off. I have knocked back the tab , placed adjustable spanner on it and administered hammer blows as suggested in the workshop manual, but the brake isn't strong enough the rear wheel turns.

Help - any ideas!

It would help if I knew what size socket it was so I could buy a socket and use my air operated impact driver.

Any useful tips and or the right socket for the job would help

Thanks
Simon Nuttall

itma · Post by **itma** » Sat Jan 20, 2007 9:21 pm

Try putting it in gear and a broom handle through the rear wheel spokes at the gearbox end as well. gawd I can hear Alan`s hair standing on end already.!!
You ought not to need an air tool, do look VERY carefully for any additional locking gizmos, like grub screws etc amazing what folk did in the past.
And why are you working on it without a full set of whitworth spanners and sockets?

Eric · Post by **Eric** » Sat Jan 20, 2007 11:25 pm

The manual recommends putting it in top gear. There should be just one locking washer, it has a tab at its centre hole that locates in the the crankshaft keyway and is otherwise just a plain disc on its larger diameter, but it is possible to knock it over more than one flat of the nut have you checked around all of the flats? Sorry cant help with the spanner size but an adjustable will probably spring its jaws it needs a good fit as its the impact that does the trick which is why I guess you want to try the air impact driver. It will almost certainly be a whitworth/bsf size. Measure it accross tha flats with a micrometer or vernier give me the size preferably in imperial units and I can certainly look it up in the chart.

paul knapp · Post by **paul knapp** » Sun Jan 21, 2007 3:46 am

Simon,... not a good idea to jolt/shock any crank on the end to undo a fastener!
Socket and long tommy bar, or ring spanner with a long tube over to gain leverage, once you have locked the wheel as described and have the correct tools.
Are you turning the bolt the correct way to undo?
Good luck,
Paul

Eric · Post by **Eric** » Sun Jan 21, 2007 9:26 am

Paul the workshop manual does actually recomend a "Series of Sharp Blows" to a ring spanner upon the nut to release it. I know it may sound drastic but I seem to recall that upon the Villiers engine in my very first bike they actually sold a special spanner with a beefed up end upon it inviting you to hit it with a hammer to undo the nut.

Simonn · Post by **Simonn** » Sun Jan 21, 2007 9:44 am

Thanks for all the replies, I did check the tab was completed folded back.

On the turning it the right way, I couldn't see anything to suggest it was anything other than a normal thread and hence have been trying to undo it anticlockwise as normal.

I will try and measure the nut size, but I am not sure where I can borrow a micrometer from.

I agree a ring spanner would be better, not having such a large one was why I was thinking of the impact tool.

Not sure about the broom handle though, figure I could have a sprung spoke to add to my troubles!

paul knapp · Post by **paul knapp** » Sun Jan 21, 2007 11:13 am

Eric, point taken, but I am a bit of a "worry wort" when hammers and engines are used in the same text .
Cheers Paul..

itma · Post by **itma** » Sun Jan 21, 2007 11:16 am

You won`t need a mic to measure the nut, talk about a sledge hammer to crack a nut!! Distance across the flats will only suit A/F Unf spanner sizes
I suggest you get some whitworth sockets before you go further, not a ring. and I doubt you have whitworth airdrive sockets?
Anti clock is correct but I can`t see why its so hard to undo unless there is something else locking it.
On the short AMC spokes you will not damage them with the broom handle trick, which is an agent of last resort anyway, you will of course have someone standing on the brake pedal at the same time???
Is there a second tab not turned back?, something else prevenying it coming undone I`m sure

Biscuit · Post by **Biscuit** » Sun Jan 21, 2007 2:11 pm

I have removed many a sprocket using the 'broom handle' tool between the spokes, never damaged one yet (spoke, not broom handle)

Alternatively try a soft metal wedge, ie brass aluminium, wedged between the sprocket and the top run of the chain, might shift the gearbox, but it usually works.Edited by - Biscuit on 21 Jan 2007 2:12:51 PM

itma · Post by **itma** » Sun Jan 21, 2007 3:13 pm

blimey Alan, I was`nt going to mention the wedge trick in the same post as the broom stick, I feel happier with it now!