Hi all, I finally got round to renewing the chain and sprockets on the R and blimey, was the gearbox-sprocket nut tight, even with the missus on the brake!! ended up at the local garage and got it loosened with an air-gun, and even that was a struggle.
Back home I found on the wheel hub three of the bolt threads ends badly chewed from when the chain jumped ergo three f'd nuts (serves me right for not checking through the crud before spinning them off with a drill!!) I can replace the nuts, but is there a way to re-dress the bolt thread ends, I can't find a thread file here in France.