Further to our earlier post,we have repaired the sprag clutch by replacing the spring with one from a LDV van oil seal at a cost of £12,as opposed to the £250 quoted by Triumph. Also the clutch was accessed by removing engine,turning it upside down and removing the sump and bottom engine case. this allowed us to access the sprag clutch without having to strip the entire engine down. the job took approx.4-5 hours and required no special tools,only many cups of tea! it is a bit fiddly,but can be done.