How do you remove the cylinder top?

Ib-Denmark · Post by **Ib-Denmark** » Tue Apr 12, 2011 2:53 pm

G12 1965:
It looks as I need a special long Socket for the nuts? (Believe they are 3/8"?)
Is that right?
Where do I get it?
Not at Jampot Spares!
Ib
Spring is in the air!

Eric · Post by **Eric** » Tue Apr 12, 2011 4:18 pm

You should find some tool merchants that sell long sockets.

The tool that most would have been used when the bikes were new was a tubular box spanner, as sockets were not very common then, see if you can find a source of those.

You are right a 1965 G12 did have 3/8" diameter studs with cycle threads, earlier years had 5/16" diameter.

You need to find a Whitworth spanner of size 5/16" that's because Whitworth spanners fit not just nuts for Whitworth threads but those for other threads as well e.g. BSC British Standard Cycle that you have, but as the BSC thread is finer in pitch than Whitworth the nut is smaller across its flats so a 5/16" diameter Withworth nut will be the same across flats as a 3/8" diameter BSC one.

Its easy really when you get to understand it, the spanners are based upon the diameter of the Whitworth thread but finer threads have nuts that are smaller, by one spanner size.

Eric · Post by **Eric** » Tue Apr 12, 2011 4:24 pm

Try a search in Google I found several sources but somone is still manufacturing box spanners new in all sorts of sizes.

Stuoyb · Post by **Stuoyb** » Tue Apr 12, 2011 4:38 pm

Part number 900750 is listed by JSL as the tool to use. You will need a 3/8" socket drive and a short extension.
Did the job perfectly for me.

petert120r · Post by **petert120r** » Tue Apr 12, 2011 5:54 pm

Box spanners are not a good idea. The hex shape can easily wear and cause slip, damaging spanner and nut alike, particularly head nuts which need to be torqued to 22 ft/lbs.

Trying to remove a knurled off head nut can be great fun!

Stuoyb is right about the JSL socket but if you can't get one there King Dick do a slim 1/4" Whitworth socket with a 3/8 drive. I've used mine for years.

The 3/8" studs take a 3/8" BSCY nut with a drilled out 5/16" nut welded on top so you can use the standard socket.

Don Madden · Post by **Don Madden** » Tue Apr 12, 2011 5:58 pm

The nuts for the 3/8in studs are the same as for the cylinder base on singles & have a reduced hex size so that the same thinwall socket as 5/16in studs fits. I rotated a normal 5/16BS socket against the grinding wheel untill thin enough to slip down the fins. The same socket also fits the recessed bolt holding the fork damper. Cheers, Don.

Chazzyb · Post by **Chazzyb** » Tue Apr 12, 2011 6:29 pm

quote:
The same socket also fits the recessed bolt holding the fork damper.

I'm sure I found a 13mm socket did that...