Honda CR500 clutch problem

[rumpelstiltskin]

Hi,just bought an old (1988)CR500 motocross bike.There's an intermittent problem with the clutch.Sometimes stationery the clutch can be pulled in fine then you can pull away.Other times you pull the clutch in at standstill to select first,after the gear is selected the bike pulls forward and stalls with the clutch still fully in to the bars?Anyone any ideas?

[Silver993tt]

dodgy clutch cable? Maybe worthwhile replacing it, can't cost much.