I have a strange gearbox problem. I bought the bike 2nd hand (07 280pro) shifts up ok but to get it to shift down I need to pull the lever up a little and then shift down. I have been through the eccentric shift adjustment without sucess the problem is, the little click they talk about doesn't exist for my bike shifting up or down. The bike stays in gear no problem.

Any ideas????

You might try replacing the top hat and shift spring. They are usually sold together and it`s cheap.

I've looked at it and it seems intact. Is it still worth replacing if it looks ok??