Hi there, my bike is a 2006 classic vulcan vn2000 there are two questions: 1. every time I reach the 90 miles/hour a red warning light (the oil pressure/temperature light) goes on. Is this just a warning light as to let you know you are going too fast on the road or something really goes wrong with the engine. it only lights at 90 milles/hour or faster. 2. I have detonations when releasing the accelerator or going downhills. can you give me some advise? thank you