Just pulled my cbr400 nc23 forks apart to replace the leaking seals, on inspection of all the parts i found the top fork bush has a coating on the inside of the bush which is peeling off, looks like a magnetic lining (obviously it isnt though), possibly friction reducing lining.....? The lower bush also has the same lining (but on the outside of the bush this time) which is again peeling off. So my question is, should it be there or is it just crap that has built up around the bush? should i leave it, sand the coating off or replace the bushes?

Couple of pics

Top bush


Bottom bush


Thanks

Yes it is an anti friction coating and i would suggest they need replaceing before they get any worse as they are not to exspensive all the best rick