FH - steering head bearings

After the last trip, back in the workshop, a quick check revealed the expected loosened head bearings - wheeling the bike forwards and putting the brake on reveals a 'jolt' from the headstock which you can hear. To check them more physically, put the bike on the centre stand and put your thumb here in the dim & dark recesses of the top yoke, across the gap between the dust cover and the headstock:

With your other hand, grasp the front wheel and rock the bike backwards. This has the effect of pushing the steering column up through the headstock against the weight of the bike, and your thumb will be able to feel any movement. Don't vigorously rock it backwards & forwards - you don't want it rolling off the stand.

Mr. Waller suggests lifting the weight off the front wheel to perform this job, bit since the Square Four is on the bike lift I use the method described above.

So, having found some movement we need to sort out the problem. First slacken off the lock nut under the top yoke with your head race spanner; Clay at Acme Stainless has these, but you can also pick original ones up on eBay. 

This time, I had to loosen the handlebar clamp to get enough access to the stem nuts. Be very careful not to damage the paint on the tank - make sure the spanner fits well (so that the spanner doesn't slip) and that the tank is protected (for when the spanner slips):

Now, grasping the wheel again, roll the bike backwards against the centre stand whilst attempting to tighten the lower of the two nuts. You will find that the nut is now loose and can be tightened down - you will want to perform this feat of coordination two or three times.

When you are happy that the bearings are snug, and you can feel no more movement, tighten down the top nut. Move the handlebars and satisfy yourself that they are not binding anywhere. 

If you use your steering damper, reset it and you are good to go.