Raise the forks in the triple clamps 4-6mm, set the rider sag using preload adjusters to 35-38mm, start with the rebound 7-8 clicks out from full hard. You can go higher with no issues up to 10-12mm (try 2mm at a time). Set the rebound to where it tracks the road, not so much that it's bounces off the top of every road irregularity; that will cause a wobble/headshake for sure. The springs are too soft, especially the rear (the spring has sooo much preload on it that even in the softest setting the rear of the bike has no free sag. So under hard acceleration you have too much weight transfer to the rear, (especially if you have some weight on you), the front end gets light (it's got too little weight on it from the Factory with the forks in the stock setting), the front wheel with virtually no weight on it is skimming the pavement, worsened with too much rebound damping, your arms are acting like sails/wings....ya it's going to headshake! :-)