A design from the 1950s or before. The Ducati singles, with one exception, use non-caged ball bearings, 24 in the top and 24 in the bottom. As ball bearings wear there is no way that any adjustment can be made to take up this wear, taper roller bearings would be much better. The fact that they are non-caged does not help either as each bearing needs to be individually inserted into the bottom race and then the top race, as soon as one 4.7mm (3/16″) ball escapes the whole lot has to be dismantled again. Many people have found that as they dismantle the top yoke all 24 balls fall out of the bottom bearing and roll around the garage floor. This did not happen to me as I had prepared.
I ordered 100 stainless steel balls from ebay for around £4.50 and am waiting for delivery. The play is quite extensive in the steering at the moment so I thought that it might be a good idea to clean and grease the existing bearings. After removing all of the balls and removing all signs of grease from them I counted – 47 bearings! One had gone, but nothing was on the carpet in my work area and I had heard nothing fall, so assumed that there had only been 47 in there in the first place. This is an area that needs constant maintenance so I assume that in the 50 years if Dinky’s life, they have been looked at before. Some pictures:
Looking down into the steering head with both the top and bottom inner bearing cups fitted.
This shows the stem fitted and the large (standard) gap around the tube.
When the top ball bearings are fitted into this cup with grease to stick them into place then the top cup can be fitted to hold the balls in place. The top yoke would then be fitted with the nut to tighten everything up. It seems that a previous owner had not been a fussy as I am and one ball had escaped without his noticing. The ball had ended up between the bearing cups and the stem resulting in some damage to that stem, as can be seen in the following pictures:
I can only assume that the result would have been very rough steering and that he eventually dismantled it and removed the damaged ball and reassembled the whole lot with 47 balls.
I shall probably drop some weld into this area and refinish it, but it cannot be seen and does not really make the stem weaker, so might leave it.
I think that a taper roller bearing kit might be on the cards for next winter!