replace them. too when you`re already at it. They are way less expensive then the bearings.

A general question about bearings, specially wheel & swingarm bearings. Do they have a 'half value period'? I mean considering this bike stood for 13 years can one assume they are all still good? I guess I`d personally change them all for my own better conscience but would it be necessary ?

G.

Yes G, it seems having got the bike dismantled this far back it makes sense to replace all bearings (and seals)as they are relatively cheap; the thought of putting it all back together only to have to strip it back again in a few weeks to replace something like a bearing is not a nice one. Jon

As I recall, mine where fairly dry as far as grease, but had some moisture in them. Probably from riding in the rain and washings. I had quite a few miles on mine, in the 40,000 mile range. The steering was notchy and that is how I knew to change them. I just replaced the bearings and the races, I re-used everything else. I would think if enough grease were in the bearings, then moisture couldn't get in. I check mine during the winter down time now.
du907

Nice looking 907 du907.
I think the main problem with bearings and their seals, in this case the steering, is that they were designed to keep out rain and road spray and not pressure washer spray - Be careful where you squirt
I now have the new bearing cups installed and am about to start the rebuild of the M1R forks, have new seals etc. but i am going to repaint the sliders as they have some alloy exfoliation where the guard covered them. I am going to replace the original stanchions which are pitted, with another pair from another set i have. Also have my second hand new tyres - will be fine for MOT test and 'gentle' ride out's either way they will have to do! Jon

Your posting above about working on the forks reminded me of when I rebuilt mine a couple of years ago. I used the 907 OEM seals and that summer both of them leaked. I then used some from a 900ss that I modified and they have been in and leakless for about 3 years now. As I recall I took the 900ss seals and ground the bottoms a little, just enough to take off the rubber coating and left out a thin washer/spacer to make them fit height-wise. They were the same inside diameter and total outside diameter, just a more robust seal.
Just something for you to ponder.
du907