Sorry, I thought I had put the numbers in! In the example on a 4s I went from standard (15/39) to 15/43 (standard ST4). Not sure what's standard on the ST3 - a quick Google suggests it might be 15/42. The ST3 might use a different front sprocket type to the ST4s, though.
Googled a bit and if either of the two previous owners didn't change anything it's the standard 15/42, so I'll have to decide the increase after the initial checks are done.
The good news is, it was just a slack throttle cable. First chance to look at it was today. Took the twistgrip apart and re-assembled it to make sure all was ok - started her up and let her run to warm then adjusted the cable out until a slight rise in revs then backed it off a tad. Went for a ride and it was perfect, completely changed. There's no smell of petrol now that some is used so I can only assume I put too much in then put her on the side stand while opening the garage door. Thanks all for the input, much obliged.
