First.. no the needle is not slipping
I have a 2007 S4RT with the gauges replaced by SOS Diagnostics. Not sure what bike the gauges came from (the face is black), but something with a different magnetic pick up because the speed was way off. It was reading 44% too low. So I run a 12oclocklabs SPEEDODRD speedometer corrector to fix it. I've been on this set up for a couple years now with no problems. It was way more accurate then any bike I have had.
Recently after a hard acceleration the speedometer will just go to zero. No movement while riding, the needle hasn't slipped, it just doesn't move. This has happened twice so far on two different days. I can pull over, shut the bike off and turn it back on. The gauges will sweep and start working like nothing happened. Is there anything I should look at in particular? I have been riding more aggressive lately so it seems like I am accelerating faster than how I have ridden in the past. I didn't think I was too quick for the gauges though haha.