I was stuck like this too before with another car but a couple of ways to get around this is either drill/reamer your spur - either 2 opposing holes or 4 for balance or, if you dont change gearing often and have a ratio you know works for the track, take the top deck off, get the mesh right, tighten the screw that's not blocked by the spur, take the spur/layshaft off to tighten the other one and re-assemble. absolute pain but at least it wont stop you racing
