Hello Mate,
I have been running a 242 for a while now and absolutely love it. It steers very well with quite a roomy feel to it. The power is very good with enough beans to get you up anything.
Mine however is not standard. After running it for a bit, a 304 came up which I bought for parts, as a lot of parts are interchangeable.
Currently mine has;
304 seat/tank because it's plastic so modern petrol doesn't eat it, slimmer and fits with a little trimming around the shock mounts.
304 ignition cos it's electronic.
304 gearbox, clutch and primary because they have changed the primary ratio to speed up the gearbox which takes a bit of load off it. The 242s tend to be a bit hard on the gearbox and any little helps. The downside is that you have to run a tiny gearbox sprocket to get the gearing down again. The upside is that the 304 clutch is MUCH nicer and even lets me select neutral!!!
OKO 26mm carb cos the standard Amal will be worn out and the OKO costs much less. I bought mine from a company in Germany Called Scootermax.de and it was about £60-00 delivered as opposed to about a ton for an Amal. If you go that route don't go buying a load of jets and stuff, I can tell you what I'm running and you can just order them. It's pretty close as delivered.
304 forks cos they are stiffer, use a better mudguard mount, have much better axle clamps with a bigger axle. You have to buy different bearings and get some spacers turned up and a make a torque arm if you want to stay drum braked though. They were worth the trouble though.
As for suspension, if you weigh 17st. you are probably going to need stiffer string rather than just spacers but to start with I would try 30 - 40mm of spacer and oil 125mm from the top of the tubes, collapsed all the way to the stop and spring out. As for shocks stiffer springs or preload all the way!
Hope you stick with it, they are really good bikes, but I don't think you will be able to plan your retirement on it's future value!
Where abouts in the country are you?