I'm nearly ready to try my 'supermoto' converted 350 SXF at a speed hill climb and the sprockets need changing to give suitable gearing. Some hills need significantly higher gearing than others and all need higher than MX. To give the greatest number of possible variations I like to have a choice of two gearbox sprockets and two or three rear sprockets. I got an additional 15T sprocket for it (14T original) but whilst the splines and offset are exactly right it looks as if there isn't enough clearance between the chain and the clutch slave cylinder to run it - at least with the Regina chain it has now - though I will be replacing that anyway as it is pretty worn. I'll run a HD non-o-ring RK as do on my other hill climbers as my local dealer always has them on the shelf and they work well for me. The clutch slave cylinder bears witness to have being worn by the chain already but I guess that may be due to being run at some time with a very slack chain. So can it be done? No mention in the manual of alternate gearbox sprocket sizes and I can stock up on a range of rear sprockets but it is good sometimes to have the fine tuning option of a 15/4n combination to get the gearing perfect to hold one gear through a series of bends. Despite playing with gearing calculators I just won't have a real feel for what I need to use until I give it its first run up Prescott hill on Saturday.