http://www.yamahaownershandbook.com....C-28199-33.pdf
I'm not sure which engine is in the bike. 07?? 09?? They all vary a little. The early models had dipsticks. The later ones use a window. Not sure where you're finding the check bolt? Next to the window? The other consideration is that in the Yamaha they use the frame to hold oil as well as the engine. Both have drain plugs which need to be dropped. Not sure if the GG uses the same setup. I'd imagine so. Further reading indicates that the alloy frames used an oil tank (rather than frame). Looks like the drain bolt for this is under the engine towards the front. There is also a line with a screen in it which should be checked occassionally. So if you didn't drain the oil tank you could have overfilled. The other thing is that the oil level will show low until up to temp, so if filled properly cold, it will be overfilled.
For an 09 YZ250F
Oil change: 1.05L
With filter change: 1.15L
General consensus is that you are best using the measured volume. If only overfilled even a bit it will blow out the breather.