I'm working on the same problem. My '86 245 has a very stiff clutch while my wife's '88 240 clutch is very easy to press, even easier than my daughter's Honda. Since the '88 has a new clutch, I assumed that was the reason it was easier to press. However, if your clutch is fairly new and still hard to use, my theory may be wrong. I did put a new clutch cable in my 245. The clutch action is smoother but just as stiff. The old cable's connection to the clutch pedal was hanging on by a thread. One side was completely worn through and the other nearly so. It's a good thing I replaced the cable since it could have let go any time. If you've had a stiff clutch and your cable is old, you should check that connection at the pedal.

Because my clutch chatters a bit when it engages, I believe it is worn and may have oil from the rear seal on it. I will have it replaced soon and we'll see if it is less stiff. I'll post the results here.