Sealing the headstock bearings

[Neil E.]

As part of measuring up the frame for my damper mounting, I decided the stock dust cap restricted access too much. The white plastic dust cap (seen sitting turned over on the fork cap) covers part of the headstock where my clamp needs to go.



The stock dust cap doesn't seal the upper bearing in any way. I made up a PVC washer to replace the dust cap. A #328 viton oring fits nicely around the top bearing. The new washer puts a light squeeze on the oring. This seals the upper bearing. Some grease on the washer allows the stem locknut to slide on the washer as the handlebars turn.

The 328 viton oring is 1.875 x 2.250 x .187 nominal and measures .210 thick. The PVC washer is 1.380 x 2.230 x .070. In case you want to add an oring under the stock dust cap, measure everything carefully. The cap is about .060 thick, so it may not squeeze enough on an oring.



The lower bearing is sealed by the factory oring. A chromed steel ring is mounted on the steering stem. The face of the ring is on a 45* angle and locates the oring. The chrome ring swivels inside the oring as the forks turn.



Keep an eye on this oring. Make sure the oring stays stationary as the forks turn. If there is not enough grease inside the oring, it may distort and let water into the lower bearing. The factory did a good job greasing the headstock.

You can also see my new steering stops. The plastic insert in the factory stop is a nice idea, but can get squished down easily. I decided to make a larger plastic stop. An 8mm setscrew is held in the bottom crown with loctite. A black UHMW spool is threaded over the setscrew and also secured with loctite. Only the plastic makes contact with the frame since it is about 2mm proud of the setscrew.

I now have 42* of motion on the handlebars. This is the maximum possible fork lock travel. This leaves a 3mm gap between the tubes and the frame at full lock.

[Neil E.]

Just wanted to add that you need to work a bunch of grease into the factory keyed steering lock to help keep water out.

[GMP]

Good job. What you did is similar to what the old pre '00 bikes had, they just used the same washer and oring thats on the lower bearing on the top. I did this on my '00 when I mounted a Scotts. For my '07 I used the Scotts/BRP steel cup with an oring just a bit larger in OD than the cups ID, for a stay put fit. The cross section is about the same as the steering head thickness, and with the paint removed, seals between this surface and the cup. Either way works good, I got a little moisture in the bottom but my fault for stretching service too long.

[husley]

great info!

thanks