I've lived in the area most of my life, and the sad truth is that Woods in Abergele is not a bad bet. There are a couple of smaller shops you could try including 'road and trail' at the top of the hill (four crosses area) of Menai Bridge (very unlikely, small, non KTM), or the dealer behind Tesco's in Bangor (a bit bigger but not KTM).
Your best bet is probably a dealer in Colwyn Bay (they often have desert prepped KTM stuff in: Colwyn Bay Motorcycles Ltd, Groes Rd, Colwyn Bay, Clwyd LL29 8PU, Tel: 01492 535959 ).
There is also a dealer in Denbigh but I dont think he deals in KTM stuff, he's mainly road bikes (and further than Colwyn Bay).
If you were really desperate and got to Woods in Abergele and they didnt stock your sprockets I know they currently have a 2002 model 640 Adv on a 2003 plate (I went to look at it last week). They may be prepared to take off the sprockets for you at a cost.
Other than that you're in Chester, Liverpool, Manchester.....
Hope that helps,
[This message has been edited by davidlomax (edited 30 March 2005).]
[This message has been edited by davidlomax (edited 31 March 2005).]