Duncan,
Re: Rusty nuts & bolts on your rear suspension/hubs.
First thing I do is wire brush the worst of the surface rust off the exposed threads. Then I spray motorcycle chain grease (coz its sticky) over the threads. That will at least make things easier when the nut starts to turn.
Do the bottom two 17mm bolts that hold the strut to the hub first, remove the 4 x 13mm top mount nuts till last.
Rear suspension on a Beta, if rusty, is going to be a pig, theres no two ways about this. The two 17mm bolts that hold the bottom of the leg to to hub are seriously hard work unless you have a compressor and an air gun. You may get the nut off easily but this is just lulling you into a false sense of triumph. The bolts themselves rust and hence become roughened on the shaft that is hidden from view at the rear of the hub, this rustiness fouls them from sliding back through the holes in the hub body - get a drift and a big hammer and don't be surprised if the bolt suffers severe damage.
I put grease on it all and the air gun spins the bolt, while I use an old screwdriver as a kind of crude lathe on the shaft of the bolt to remove surface rust - more grease and then a friend to drift the bolt out while spinning with the air gun. I did this very recently and it still took me a fair amount of time to get the rear struts off!
You will also find that the design of the strut body has a lip that fouls a socket going on so your going to need a good ring spanner.
I'm not trying to be all doom and gloom - but if things are rusty down there then be prepared for a couple of hours fight.
I will dig out some spare bolts just in case you decide to chop the heads off and drift out the remnants. At least you'll know that there are spare ones available if need be. I'll PM you with how many I find in my boxes of bits.
Stick with it - we've all been there and lived to tell the tale
