I just bought a 5 speed cluster from the Uk, and like you say, no instructions........That in itself is quite poor in my opinion, not everyone can work out these things. There have been several versions of the 5 speed box that I know of, the ones here started back in the 90's when the RTV's were being created. The cam plates of the variants have all been different, and the ones here need more rotational travel than a stock 4 speed plate. This meant that installing one to an assembled engine was very difficult, as the bevel stop in the roof of the gearbox housing needed modification to allow for this extra travel. The kits made by Quaife don't suffer this issue as they seem to have worked out how to select all gears with the same travel as a stock cam plate. I did have an issue with one where the spindle protruded below the hole in the cam plate bevel gear and this fouled on one of the selector forks, as there is one that passes under this area. The ones from here did not have the small parts that limit the travel of the G 66 AS lever either, probably because of the extra travel mentioned before needed for the cam plate. Like all these mods to these bikes, you have to trial fit everything and assume that some fettling will be necessary........... I'm well use to it now. The 5 speed box which was one of the later ones that Terry supplied for a time, was the one I used in the HRD twin racer I built. I had to carry out some re-shimming of the gears and shaft end floats, this was because the cases had the centers machined from weld repairs that had left a gap in the cases, my guess is we lost about 0.020" from the joint face. Apart from that, the gearbox has performed perfectly and it is fabulous to use, coupled to the Bob Newby belt/clutch kit that we used............ Just for your info Tim, we run 40 weight Morris castor oil in the box. Cheers................. Greg.