The standard steering damper is a friction damper which should be called a stiction damper, once moving the friction DECREASES, the opposite of what is required, this is why they were dropped from suspension as soon as hydraulic dampers came along.
Further to above, today I cut 6mm off the temporary Benelli springs I had fitted, from 400mm to 394mm. This dropped the back of the bottom link to the recommended height. I also adjusted the AVO damper to the softest setting. The steering felt marginally lighter walking around, but the suspension felt a lot softer and better controlled when riding. Then I had an opportunity to ride another Comet, we took both bikes for a trot up the valley past my house for about 6 miles of winding, undulating rural road, swapped and rode home. Interesting back to back comparison between the Comet with modified steering and one with standard steering and friction damper.Just for the record, I have recently fitted one of Norman's JE steering stem/yoke assemblies, without an hydraulic damper, to a Comet. The change in steering sensation took me by surprise. When walking the bike around, the bars wanted to "flop" towards full lock. When riding, the steering felt heavy up to about 25MPH, then it felt more normal, but required positive counter steering input.
I put this down to the increase in trail.
Prior to fitting the new yoke, I drew it, then drew the original for reference. According to my measurements, the bottom link pivot has moved back about .539" and down .723" (If anyone else has worked through this and has different figures, please feel free to correct me, my maths and drawing can both be a bit average)
Keeping the calcs simple, moving the pivot back 1/2" means the axle moves back about 1 3/8", a theoretical increase in trail of about that amount. It should come as no surprise to feel a distinct change in feel of the bars. An increase of 1 3/8 trail should also ensure total stability, but as there are always other factors which can contribute to weave and tank slappers, no guarantee of tank slapper free steering.
The sensation had enough effect on me that I called Greg Brillus, who has fitted many of these units and asked if I may have done something wrong with fitting. His response was; he always fits an hydraulic steering damper with the stem and has not experienced what I described. We agreed that the internal friction of a steering damper probably masks the sensation.
Did you buy a comet?Further to above, today I cut 6mm off the temporary Benelli springs I had fitted, from 400mm to 394mm. This dropped the back of the bottom link to the recommended height. I also adjusted the AVO damper to the softest setting. The steering felt marginally lighter walking around, but the suspension felt a lot softer and better controlled when riding. Then I had an opportunity to ride another Comet, we took both bikes for a trot up the valley past my house for about 6 miles of winding, undulating rural road, swapped and rode home. Interesting back to back comparison between the Comet with modified steering and one with standard steering and friction damper.
We agreed that the suspension of the modified-steering-bike is definitely nicer, the "standard" one has single Comet springs and standard bushes which make it feel firmer.
The steering of the modified bike is noticeably more "sluggish", requires more counter steering input but is totally stable. Stepping off the modified bike onto the "standard" bike caused me to "oversteer" initially, I pushed the bars harder than needed and the bike turned in noticeably quicker. It took a few corners to readjust, but it never felt unstable.
This has to be the most succinct explanation yet.The increased leverage provided by the full extension trail of the standard fork (5.28 inches) and the decrease in the moment of inertia of the steered assembly which occurs when the fork extends (38% compared to the MoI at full compression) are the reasons why the Girdraulic fork is so prone to tank slappers. Essentially the self aligning force generated by tyre is given a longer lever to shift a smaller load!
No, not so lucky Gene. This bike normally resides in the 'Naki, just came to me to have some maintenance and this steering mod done.Did you buy a comet?