There is a two bolt little round plug at the "top" of the primary case.... It is held on by two 1/4" countersunk Allen Head capscrews.... take it off and see if the chain has a lot more thant about 5/8" of up/down movement.... if it is lots more, tighten it.... there is a "setscrew" with a jam nut under the footpeg area.... (for stock "mid" control Sporties, anyway) you loosen off the jam nut and tighten it with an Allen Wrench.... until you have about 9/16" of total up/down movement....