I have a curvy which has a big bore kit to take it to 700cc.
It's a track bike so doesn't get used much, especially after some little people made an appearance.
Anyway, after being laid up for 2 years it started to burn oil going through a reasonable amount in two days track use. Another lay up for 6 years this time and the oil use is now impressively bad. As in I used a litre in a morning and two of the sessions were red flagged and ended early!
My thoughts are it's likely to be one of two things.
1) Rings have "stuck" (maybe due to slight rust in the bore) and oil is either being sucked past or the crankcase is being pressurised and it's blowing oil into the airbox.
2) Valve stem seals have perished, cracked and it's sucking/leaking oil past.
Any other options it might be?
Equally are there any tests I can do to indicate which it is likely to be?
While I don't really want to open it up as the oversize head gaskets are rather pricey it's got beyond the "just keep topping it up" stage, more to the point I don't want to just do a top-end rebuild if there is something likely to be contributing down below.