Headstock Bearing

I haven't bothered to find out how you adjust the headstock bearings on an ST4, but they are generally all the same sort of procedure.

To check it is the bearing adjustment, sit on the bike and rock it forward with the front brake on - use the left hand if you can, to feel the area just under the top yoke where it is over the headstock - (sometimes you can see as well). If it is bearings, you will definitely feel it in your finger.

However, it isn't always just adjustment being out, it can also be wear in the bearings - either grooved or lumpy.

You need to raise the front wheel with the bike upright to check further.

Once the wheel is off the ground, get hold of the bottom of the forks either side and push / pull backwards and forwards.

Again, you should be able to feel the slack and possibly see it with any fairing off (make sure it isn't wear in the fork slider bearings).

Try turning the front wheel / yokes from lock to lock - you may feel any issues with the bearings as you do it.

If all seems OK, and just slack; then tighten the headstock bearing adjustment - it is best to do it so that as soon as you feel the adjustment has gone tight, then back off by about a 1/4 turn. (Bearings too tight can cause weave).

Check lock to lock again - Smooth or lumpy?

Lumpy definitely means change the bearings.

If smooth, you may be alright, but I would suggest greasing the bearings anyway - which means top yoke off at least, and dropping the forks down so you can get at the bottom one as well.

 

You will need a special tool for tightening, also there are 2 pinch bolts that need loosening IIRC

 

Welcome to the forum

 

The two pinch bolts only need to be touched if you're removing the headstock tube or rotating it.

 

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