There are at least two adjustments that may help. Here is a photographic illustration of the adjustment that mickmate describes:
http://www.craigscobras.com/tips/blinker/index.htm The other thing you can do, as described in some of the posts above, is loosen the Phillips head screw behind the turn signal lever, then adjust (rotate) the signal lever assembly left/right (or up/down) to best position. The lever in my SPF was at the 3 o'clock position. Recommended position is closer to 2 o'clock. These two adjustments helped with my cancellation issue, but it still was not right. I spent some money to buy a new switch indicator (not cheap), available from Hillbank Motorsports,
http://www.shelbyshop.net/product_in...ucts_id=156173, had that installed, and my turn signal now cancels perfectly on both sides. This is obviously not a performance issue, but it bugged me until I got it right.