I've got some 2001 Z4 air forks. How can I tell when they need new bushes? There's a fair bit of stiction when you bounce on the handlebars, which was helped a bit by stripping them and using Rubberlube (a genuine Delphi / Lockheed product name!) on the seals.

However, I've read that bushes can cause stiction in some Marzocchi service manuals. Is it a case of manually checking for play, or is there a visual inspection like on some modern forks? Is there a low friction coating that can wear off?

As far as I know, these forks have only ever had oil changes. But they've not been used that hard or much by me in the last 5 years, as I don't ride loads and run rigid sometimes.

You should be able to see the play by rocking it while squeezing the brakes. Look at the seal on the top of the stanchion. Not sure much is too much

I had a pair of mx comp for 6 years and never got a service and worked brill. they where used really hard, so they should be fine

My old marathons need new bushes, they wobble quite badly. Took them apart but had no idea how to get them out and new ones in. Not really worth sending them somewhere as they are so old.

The older "classic" bombers had nice removable bushes – like long top hats.

They should slide out (possibly destroyed in the process) and the new ones slide in.

Not familiar with the smaller bushes.

Ahh right. I don't think there's any play from when I've waggled them in the past. I'll have another waggle in the morning.

Might the Marathons be for sale? I seem to remember they were good forks back in the day – what year are they?

Yup, those marathons are the shizzle. Got a 6 year old pair that have had only the one oil change in that time and are as good as any others I've tried.