Scotchmist
XS650 Enthusiast
Hi all,
I'm presently running a pair of FZR 600 forks on my bike using the original top and bottom yoke and stem (which matches the XS650 stem). In the present setup there are a pair of locknuts that adjust the preload on the tapered headstock bearings. There's then a small gap between the two locknuts above which is the top yoke. The top yoke is suspended above the locknuts by a taper on the stem and is secured by a large dome nut (see images below).
In essence, I want to reduce the large gap between the top of the headstock and the bottom of the yoke to improve the appearance of the front end and to lower the bar mounting point. As I'll be making custom yokes anyway (to improve the fork geometry/handling) and am happy to modify the stem, I thought it might be worth rethinking how the preload on the headstock bearings is controlled. Looking at a few other bikes I've noticed that they have only one lock nut below the top yoke (see first image below). My assumption is that when the top dome nut is tightened, the yoke is forced down onto the bottom locknut (as the yoke is not located on a taper and is therefore free to slide on the stem) and therefore in essence acts as the second locknut.
So, onto my questions.
1. can someone confirm that my assumption about the function of the single locknut headstock arrangement is correct.
2. would copying the arrangement work for me if I fabricated a top yoke which was free to bear down on the bottom locknut whilst the top dome nut is tightened and could then be secured with a pinch bolt (as in the drawing below)?
3. Are there any alternative arrangements that do away with the locknuts completely? I've seen a few bikes that seem to have almost no gap between the top of the headstock bearings and the bottom of the yoke.
I'm presently running a pair of FZR 600 forks on my bike using the original top and bottom yoke and stem (which matches the XS650 stem). In the present setup there are a pair of locknuts that adjust the preload on the tapered headstock bearings. There's then a small gap between the two locknuts above which is the top yoke. The top yoke is suspended above the locknuts by a taper on the stem and is secured by a large dome nut (see images below).
In essence, I want to reduce the large gap between the top of the headstock and the bottom of the yoke to improve the appearance of the front end and to lower the bar mounting point. As I'll be making custom yokes anyway (to improve the fork geometry/handling) and am happy to modify the stem, I thought it might be worth rethinking how the preload on the headstock bearings is controlled. Looking at a few other bikes I've noticed that they have only one lock nut below the top yoke (see first image below). My assumption is that when the top dome nut is tightened, the yoke is forced down onto the bottom locknut (as the yoke is not located on a taper and is therefore free to slide on the stem) and therefore in essence acts as the second locknut.
So, onto my questions.
1. can someone confirm that my assumption about the function of the single locknut headstock arrangement is correct.
2. would copying the arrangement work for me if I fabricated a top yoke which was free to bear down on the bottom locknut whilst the top dome nut is tightened and could then be secured with a pinch bolt (as in the drawing below)?
3. Are there any alternative arrangements that do away with the locknuts completely? I've seen a few bikes that seem to have almost no gap between the top of the headstock bearings and the bottom of the yoke.
