Hi,
CBF1000 2006 ABS 54,000 miles.
Purchased in June/July, and has developed an issue with gear shifting between any set of gears and at random times; and so yes it is fair to call it "intermittent," but does occur almost every ride. The issue is going up the box, and works fine all the time down.
Issue is mainly that it refuses, and then you have to go again.. or perhaps a third time.
Oil and clutch fluid were changed around the time I got it at 53,000 (forget the exact 100's were in terms of mileage). Oil is 10w40 Halfords part synthetic and does look rather dark already (not sure if 10w40 performs worse than 10w30 on this bike in cold weather, but never had an issue with 10w40 on other bikes in the past at this time of year like this).
Didn't change the rubber seals on the clutch slave master cylinder, and so have no idea what condition they're in or how old it is. Likewise I know there's a bearing on the shaft in the engine casing that I've not inspected.
I did adjust the gear linkage rod (the horizontal one) to adjust the lever position not long after I got the bike, but didn't touch the vertical one. Given that it shifts smooth as butter sometimes I probably would have noticed closer after that adjustment if it was the cause and would occur all the time if I'd set it too high (not allowing it to go up the box with ease).
Clutch lever positions make no difference (adjustable lever of some silver kind, no idea if OEM).
The fact it sometimes goes into neutral (postiive, not false) between 1st and 2nd sometimes may hint that the lever is adjusted wrong at the foot? Hence sticking rather than complete refusal when it occurs between 3rd and 4th, for example (doesn't matter what gear it is just seems luck of the draw).
I am shifting at low revs just because the roads are damp and would rather not use too much of the bikes power. Does the CBF hate being changed gear down low?
Any ideas?
EDIT: I did just attempt to wiggle the shaft where it goes into the bearing and there is quite a bit of movement, not sure if that's normal?

