[Sectorsteve]

C5 2012. i think its about 40-45 but im not sure. i need to buy a socket for it...
oh doh i just realised i could have measured it....

[High On Octane]

Re you talking about the crank nut or the counter-shaft sprocket nut?

[barenekd]

46mm as I recall.
Bare

[Ducati Scotty]

1 13/16" fits just fine and is usually easier to find and half the price of the metric socket.

Scott

[Sectorsteve]

the 18 tooth sprocket. yeah 46mm sounds about right..thanks!

[Roeland]

A shifting spanner also works but could damage the nut if not careful.

[barenekd]

A shifting spanner also works but could damage the nut if not careful.

What the hell is a shifting spanner? Is that a tool for the gearbox? Or are you talking about a Chinese Knuckle Buster? If the nut is as tight as it's supposed to be, a Crescent wrench won't work very well. You can't get a straight shot at the nut. You definitely need a socket.
Harbor Freight has a 20 Piece 3/4 in. Jumbo Heavy Duty Metric Socket Set 69562 with sockets ranging from 19-50mm. It's about $60.00. When you compare that with one Craftsman 34mm socket for $25.00, its a steal!
Bare
I have one and it certainly as turned out to be a terrific addition to the tool collection.

[Ducati Scotty]

+1.  The nut is below the level of the case.  No way to get a regular wrench on it.  And I needed an impact to get it off.

Scott

[Royalista]

+1.  The nut is below the level of the case.  No way to get a regular wrench on it.  And I needed an impact to get it off.

Scott

The recommended technique though is hammer and chisel. It's in the book.
And a file to cover up.
Honest, it's the truth.
It also was a bit of a secret. 

[Ducati Scotty]

I know that method and I've used it BUT as bare pointed out, it's not very nice to your bearings.  I think I spent about $60 altogether on an electric impact, socket, and adapter.  Totally worth it, and now it sounds like a Le Mans pit when I rotate my tires

Scott

[Royalista]

Aye, and Steve McQueen coming around the corner. 

[Sectorsteve]

tryna find a 46 mm socket here is like trying to find hens teeth.
the front sprocket stays on for another few thousand because im off on a bike camping trip.

[Roeland]

Over here we call a wrench a spanner - and yes the first time I removed the sprocket it was with a adjustable wrench (not recommended)

[High On Octane]

If you have a NAPA near by you can buy individual over-sized sockets for about $20 each.  I, for one, don't need a $100 complete set of over-sized sockets that will never get used, as I don't live on a farm anymore, nor work on 18 wheelers.  A cordless, electric or air impact will be a very wise addition to your tool collection for projects like this.  Most times, even if you have a 4' breaker bar, you just turn the whole motor/trans and not actually break the nut loose.  An impact spins so fast that the motor/trans doesn't have a chance to spin before the nut breaks loose and comes right off.

http://www.enfieldmotorcycles.com/forum/index.php/topic,17942.0.html

Scottie

[barenekd]

The nut is below the level of the case.  No way to get a regular wrench on it.  And I needed an impact to get it off.

I sued a long breaker bar and cheater extension. I jammed a screwdriver between the case and sprocket to keep the shaft from rotating.
I don't like the hammer and chisel even thought it works pretty well, but it sure tears up the nut!
Impact drivers are great. For whatever reason, I didn't even think of using mine. Probably because I'd have to find it, then drag the air hose across the garage. The other tools were at hand. I hate having to get up if I'm already down. This is one of  those old geezer complaints.
Bare