Not long after I bought the Beemer, shortly after leaving Omeo on my way over the Alps to Bright, the 'low oil pressure' light started flashing. I immediately turned the engine off and coasted back down into Omeo to investigate. Found everything to be OK and when I turned the ignition back on the fault had cleared. After calling Southbank BMW to discuss my options, it was agreed I could continue the trip provided oil level was normal (it was) and the light remained extinguished (it did). In discussing it with Southbank BMW and my local BMW dealer the only theory that emerged was a faulty oil pressure sensor. A few months of trouble free motoring ensued and I'd almost forgotten the incident when early this year, just prior to my ride to Maryborough Queensland, the same issue popped up again, and at my insistence the local BMW mechanic checked oil pressure (which was OK) and replaced the pressure sensor. Since that time, the bike had travelled almost 10,000 km without further incident and just as I was beginning to feel confident that we had indeed found and rectified the problem, the issue raised it's ugly head again last Friday just as I was riding along City Rd Melbourne, past Southbank BMW. Once again, switching the ignition on and off cleared the problem but when I attended a book launch at Southbank BMW the next day I discussed it with Manny, the principal dealer. As this was Saturday afternoon and no service staff in attendance he immediately suggested I ring him this week and promised to investigate the issue whenever it was convenient do so.
I used the weekend to research the issue on line to see if anyone else had experienced the problem and found a useful discussion on this forum http://www.advrider.com/forums/showthread.php?t=626341
Unexpectedly, other F650GS owners had experienced the intermittent 'low oil pressure' warning and found it to be caused by the radiator cooling fan becoming seized due to the ingress of dirt, tar or just dirt. I immediately started the bike in the garage where, due to lack of forward motion I would expect the fan would operate as the bike reached operating temperature, and found that my fan was indeed not operating. A hefty nudge on the fan impeller failed to start it and it was indeed jammed.
I dropped the bike off at Southbank motors this morning and mentioned the fan issue and sure enough the fan was found to seized due to the ingress of some small stones. The bike's computer reported that it had indeed disabled the fan to protect the motor electrically. I have not yet gained a clear understanding of the link between this event and the "low oil pressure" warning but both the other riders on the forum and the BMW service guy confirmed that this is the sequence of events.
So, if any other F650GS riders are experiencing a similar issue, check the cooling fan on your bike, and if need be clear any material which may stop it from running.
My thanks to Manny and his team at Southbank BMW for the prompt attention and helpfulness.
My gratitude for getting to the bottom of this issue was soon dampened though, by a 160 km trip home through pouring rain.
Total Distance 335 km.