I have a 2002 honda 250 ES Recon. The problem I'm

drain the old oil out of it and put some fresh 10w40 in there and see how it shifts then...screw this blinking light ...does the engine kick over? great!! now just start riding it,,,its a motorcycle right? if it doesn't shift because i'm not in the right rpm range i"d get rid of it.
I shift manually with a big boot. and work those gears in with the new fresh oil, it probably has a little jam between the dogs or something.once you get it fixed quickly change the oil/filter again.
tell me if this helped. thanks!