Sounds to me like a tuning issue. May be a little too Rich, but it's hard to say for sure. Usually, if it is a clutch, The engine will either Rev and not engage (shoes not making contact or slipping excessively) or it will run normal while on throttle and die when you are on the brakes (Shoes not releasing).

Is this on the Buggy, or the Savage? If it is on the Savage, with a 2or 3 speed, it may be possible that the clutch springs for the 2 or 3-speed assembly may have worn, keeping it in 2nd gear. When it is "bogging" does it seem to run better once it starts getting up to speed? If so, this may be the problem.

I may be wrong on what I've mentioned, but these are the only problems I have experienced with a bad clutch.