Hi,
I also have an E120 and it is a great bike, but the headset is IMO a bit of anomaly, it is 1 1/8 upper and 1 1/4 lower but can only take a 1 1/8 steerer, so you can not fit a tapered fork. I need some new bearings for my headset and thought i could find them by Google-ing them but i have realised tonight, after much searching, that i will have to take the bearings out to see what is printed on them. So far i think the lower bearing is this I will be removing the bearings this week and posting the sizes on here when i have done it. Hope this helps