We have been racing the KTM 50's for a little over 4 years now (with about 2 years yet to go with my little one). The clutch adjustment is not very difficult, but it must be done
often to keep the bike running at a top level.
In addition to the advice on oil capacity, here are a few pointers:
KTMTalk is a great resource.
The clutch springs are actually cone shaped washers. These washers can be stacked in different directions to achieve the desired engagement RPM. There are a few prefered stacks, but you will find one that your riders likes with a little testing. The main thing to pay attention to when stacking the washers is the overall stack height (should be about 0.630" to 0.650"). The stacks will look something like this (())(())(())((|| where each ( is a cone washer and each | is a flat shim washer. You can change the direction of the washers to change your engagement RPM and how hard it engages. The stack I show above is the one we have always used with an overall height of 0.650".
The individual washers should measure at least 0.047". If they are below this throw them away.
Don't buy the washers from your KTM dealer unless you want to pay $0.68 each. You can buy bags of 100 for about $15 from 50cc parts or C&C racing. They also have stainless steel washers available for a little more, but they last longer.
The more often you change the clutch oil the better. If you disassemble the clutch and clean the washers they will also last longer. They quickly get caked with the clutch friction material which causes the clutch to slip. You will be able to hear a difference when it starts slipping. I usually change or clean the washers about every hour of engine run time.
Ok, so here is the most important part of it. Listen carefully.....
If you have the money, buy a Dominator clutch from D&D. Almost no maintenance, just change the oil often. We have been using one of these in the race bike for about 3 years now, and it works great!
Good luck. It's not as hard as you think it is right now. Once you go through the clutch one time you will be a pro. Remember do not torque the clutch nut more than 25 ft-lbs or you can break off the end of the crank.
Ok, I'm tired. If you still have questions, post them up and I'll try to answer.