Sometimes, depending on your set-up, it's hard to get proper clearance with your clutch or throttle cable. A brake noodle might solve that problem.
Bairdco attached a brake noodle to his clutch cable so that it clears his rear exhaust. You can get brake noodles at a local bike shop, or you might be able to get one off of an old brake system.
Using a brake noodle may also make the clutch easier to operate, similarly to how the clutch pulley works.
A warning to those looking to mod their motorized bicycles:
Most, if not all, of the hacks and mods featured on this site were made by individual hobbyists. If you are new to working with 2-stroke bicycle engines, please by aware that there's a possibility that a mod featured on this site could seriously damage your engine. Please don't try any mod from this or any other site unless you fully understand what you are doing. The owner of this blog will not be held responsible for both material and bodily damage caused by performing a modification featured on this blog. Also remember that opening up your engine may void your warranty!