Not generally. You do fine removable covers on some ARF models, and that will let you inspect the bell crank if you desire to. But for the most part, most people just use good materials and construction methods, and once the bell crank is installed and wing completed, you can have the confidence that the controls will out live the rest of the airplane and no need to inspect it. The basic rules of thumb are:
1) Don't use a metal bell crank and cable lead outs, or the bell crank will saw through the cable. This can happen in an amazingly short number of flights. The answer is to bush the bell crank with brass bushings at the cable attachment point. This can also be done by slipping a length of brass or copper tubing over the cable, then bending that assembly into a tear drop shape, running that through the bell crank.
2) Use solid wire lead outs with metal bell cranks. On most models, .030" music wire is plenty big for lead outs. The main caution here is to avoid sharp bends that may fracture and break from vibration and stress. Always have some kind of radius at any bend and this is accomplished with round nose pliers. Some of us don't like solid lead outs because the exposed ends at the wing tips tend to catch on things when handling the model and you get lots of "twanging" with that.
3) If using a plastic bell crank and cable lead outs, it still pays to bush the bell crank. My son Sean lost a model at the NATS one year that didn't have a lot of time on it, because the up lead out broke at the bell crank. In retrospective thinking about it, I think he may have just cinched the cable too tight at the bell crank when terminating the lead outs. I didn't get the chance to check them out before he sheeted the wing, but after looking at them after the crash, I'm pretty sure that may have been the cause. If too tight, you can still get a lot of stress on the cable as the bell crank moves and saw the bale through.
Search out bell crank on the forum here and you will find all sorts of different methods of building bell cranks and there operations. In the upper levels of the event with more powerful models and power plants, you need more strength. One thing that applies to all is that you want them as free and smooth as possible or it really shows during the pattern and can cause fatal results during flight. But once you learn what works and is known to be bullet proof, you won't need to have any method of inspection. A more desirable option would be the ability to adjust the push rods and maybe even the rod position on the horn.
Type at you later,
Dan McEntee