G'Day Lammy, I don't know what system your's has but my ZX50 has the starter ring gear on the variator. To hold this to undo the nut I used a universal clutch holder which I bought from our local motorbike shop. For the clutch I made one myself using 3/8" steel for the pins, the handles are made of 1/8" steel, In hindsight I should have used 1/4" steel but it still works fine. Admittedly it did take a couple of hours to make it but I now have it handy when I want it. Here are some pics of them. Hope it helps.