I think i have a problem i'm not sure,
What does it mean if th4 oil pressure light blinks for about 30 seconds after the engine has been started..
I think the oil tank is about half full..
And i think it may have turned on once during a 30 minute ride (While stopping the engine started boggling and then the light turned on. for a brief second (turned of the second i reved it up a little)
could i have a problem of some sort?

check for loose wire on sending unit (doubt it though)  I would see about checking the pressure with a gauge just for good messure. other wise  (salutes, taps begins playing in background) might be time to rebuild, soon.

Hmm, Another thing that happened today morning was a backfire when i tried to start (I think it was a backfire, it sounded like a strong pop muffled by the exhaust) only happened once then started fine...(Could that be related that someone dropped my bike yesterday (while running) Turned it right off and lifted it and ran it for a min or two after...)
What are the signs that i need a rebuild? When i checked at the shop the told me my pressure was 150... (Don't know exactly what that means..) is it normal or should i check it again ? and by what is it messured?
What are the consequences of driving a bike that needs an engine rebuild?
(It runs more or less fine Without any noticable problems except those mentioned above...)
Waiting for your reply.
Thanks.

Make sure your oil level is full. It is normal for the oil light to be on for a few seconds when you start the bike. But when you come to a stop and the oil light flickers, it indicates low oil level.
Sounds like your compression is good. Be sure to check the oil by unscrewing the dipstick  and just setting it in the hole after wiping it. Don't screw it back in and take it out to check the level. The bike should be on a level surface and either on the centerstand or held up while on its wheels.
Check the oil level fairly often as part of your preflight check.

On a side note, these bikes tend to use a bit of oil, so don't panic about that.  But do keep it topped off. Low oil is not good.

I agree with Octane (and everyone else rally). they do use a bit of oil. I rode mine 600Km one day in pretty extreme riding conditions (high elevations, staying above 8000rpm, etc) and after that ride my bike did the same. I just topped up the oil and that was that. I find even if my dip stick reads half full, the light still flickers. just always keep it topped up!