For couple of weeks now the engine oil warning light occasionally comes on, it stays on for around 30-50 seconds and then it goes off. It's not the case that it's happening when sharp turning or going up\down hill. I spoke to my mechanic about it it and he is not sure what is causing it. He said that it may be a problem with a oil sensor (maybe it got some gunk stuck to it), but wasn't sure and he said he it would be quite a lot of work to check it\clean it, he would have to remove the whole exhaust system to do it and probably it wouldn't be cheap. Does anyone know what could be causing it and is it something serious? Is it safe to keep riding the bike if it keeps happening?