Just adjusted mine this morning. Don't know what model rider you have but on mine you loosen the jam nut (the 2nd nut that keeps the brake nut from moving) and adjust the spring by turning the brake nut till it's 1.5 inches from end to end. Tighten the jam nut back against the brake nut.
Super easy to do. I am sure your manual tells you exactly how to do it.
I we knew just how old the "older model " was we could tell you.
Please post the model number from the tag under the seat.
If it is not there then the full code from the engine will at lest give an approximate date of manufacture.
