I have a 2011 gen4 with 84,000km on it (~52,000 miles) from new. Touchwood, the engine and gearbox are still going strong (and it can still take most bikes off the lights), but I have recently (last 18 months) had to perform the following maintenance:
- resealed forks;
- new clutch;
- new rotors;
- new rod and rocker springs that connect the gear lever to the clutch
- new stator;
- new chain and sprocket (first time);
Having said all that, I’ve only been to the track once, rarely mono it, and mostly commute.
These bikes have held their value very well in Australia... average private sale price is still around US $8,500 (with average Km’s).
So, would depend on how it’s been ridden and looked after, but likely to be some consumables to replace in the near future.
Hope this helps.