the speedo on my 07 690SM has become erratic and inaccurate in its display as of late. at steady speed it jumps around at varying speeds and not displaying anything close to what im actually doing. last night i was 5th gear, 4k rpms...17 mph, then 11, then 23. you get the idea. i can see that the speedo pick up is down by the front wheel on the left near the caliper. and according to the dealer, there is a magnet in the rotor (?) that the pick up senses. now i assume that the pick up is bad and needs to be replaced, but im not one to just throw parts at a problem. especially when that part is $65-70. ive looked through my repair manual but cant find any tests or specs on the subject. anyone have any experience on this? ive tried using the google machine but it just keeps bringing up peoples faulty speedometers which im not convinced is the issue.