My throttle felt really stiff before because of... a believe it or not...NEW single throttle cable. The cable would not slide through its sheath very easily at all. Mfg. flaw?? I suspected the junction/distributor box where the one cable becomes two but it wasn't that. Still it took taking that splitter tubey thing apart to ascertain the problem and that is an experience in itself! There are tricks but ya just gotta do it. If you could write instructions how to go about taking the splitter apart and putting it back together, it would be a wonderful miracle of prose! Practise and then when you're good at it make a video???