Hi Dave, you normally crack all the nuts before you remove the chains, as you have found out, it is difficult to do after the chains have been removed.
However, mate, have faith that you are not the first to do it, nor will you be the last.
Righto, to get you back on track....
First, apply plenty of WD40 or CRC, Penetrene etc, to the sprocket nuts in question.
(2) For the engine sprocket....You need to arrest the engine clutch shaft with a pair of vice grips or stilson wrench to stop it turning. Use the correct socket spanner and undo the nut...in a anti-clockwise direction it is a right-hand thread.
Tip: use some bicycle tube or scrap rubber between the jaws of the wrench or grips to help stop marking the shaft....
(3) For the roller sprocket....place the correct socket spanner with a right-angle bar on the nut (after its good soaking as above) and give the bar a
sharp hit with a hammer in a anti-clockwise direction....you don't need to hang on to the sprocket with you hand whilst doing this....a good sharp hit should crack the nut and then unscrew....
Please let us know how you get on Dave,
