Thanks for your advices. The thing is that I have done all this and I noticed today as you say, its over the sim crossings. I got myself a really ugly car for free that runs as fast as I walk and that works ok. My bike and and other bikes/cars I tried doesnt go fast (I have my bike on 1st gear) but still this happens. My friend tried the same thing with a free bike and ended up the same way. I have low prims/scripts on my avi cause I need it for a race track where they only allow low scripts so it cant be that either.
But you are right, its at the simcrossings this happens. Well, I just have to stick to my racing tracks then even though I would really like to go in a more beautiful scenery. I will look into that hangar you told me about .
Sorry Im a bit picky about apperance when it comes to vehicles and forgive my bad spelling, I'm swedish ^^