FF: Forks Steering Damper: How To Drill Holes In FF2 Without Dismantling The Girdraulic Fork.

[Paul Coene]

The steering damper as sold by Norman Walker comes with a stainless steel plate that has to be fixed to the FF2 of the stearing head. If your fork has the two holes drilled, it is a piece of cake but if not, you'll have to drill those yourself. I wasn't very keen to take the fork apart, but drilling those holes accurately with the F22 in situ didn't seem to be feasible. Defining the starting point for the drill is one thing but where will the drill turn up on the other side ? So I made a guide tool for the drill.

Or actually two of them. (you'll need a lathe to do this). Most important dimensions: the shaft diameter must be the same as the holes in the stainless steel plate (9mm) so that the guidance sits square in the plate. With the tool in the chuck , drill a small hole through the tool (for example 3,5 mm) Now, mount the plate with the 2 guide tools (shaft facing down) inserted on the lower end of the steering head and, between plate and stearing head, place a spacer with the same thickness of the flange of the tool. (for example 4 mm). Stay next to the motorcycle and check if the guide tools run in parallel to the headset. If not, adjust the thickness of the spacer (I had to add 1 mm). Use the 1/4 " rod to hold the plate in place. Now, after removing front wheel and mudguard, the holes can be drilled with a small drilling machine (the one I used was one from the Lidl, so that's small enough) and drill the holes square from beneath with the same 3,5 mm drill. After you've drilled the first hole, place a drill through the hole of tool, plate and stem so when drilling the second hole, the distance between both will be exactly the same of those in the plate. Next, remove the guide tools and enlarge the bore (in the chuck again) to for instance 5 mm. Repeat the procedure described above and enlarge the holes in the stem. Those will work as a guide now themselves to drill the requested 8 mm square enough.

I hope I made it clear. If the description sounds a bit funny (I'm sure it does) just imagine you've got mounting instructions from Aliexpress. It can't be worse, can it ?
And else, there is still something like "google translate" or similar.
I hope it helps,
Paul.

 

[Paul Coene]

I made some improvements to the text of post #1 in particular to the thickness of the spacer.

 

[timetraveller]

The problem is that no one in their right mind would offer a guarantee that a tank slapper could never occur. You asked me a month or so ago if I could offer a guarantee and I said NO. If it is possible for a modern racing bike to get into a tank slapper when millions have been spent on those since Vincents were made then how could there ever be a guarantee? Is it likely? No. Has it happened so far. No. Could it conceivably happen under some circumstance? Almost certainly yes. I have had feedback from two people so far who have fitted the damper kit to standard front ends and both feel that the damper has got rid of head shake when it seemed to start. The litigious nature of North American society is well known and when Laney Thornton was supplying his dampers they were accompanied by several pages of warnings/exclusions etc. to try to avoid such litigation.

 

[Vincent Brake]

I dont know if the chineese dampers are proportional guys.

I always used hyperpro proportional ones. Meaning the higher the speed the damper gets the damping force would be proportional higher as well.

But a guarantee a tankslapper wont happen....

Cheers

 

[Peter Holmes]

Although I agree with Vincent that the Hyper Pro Proportional steering damper is a great bit of kit, Norman supplies his entire kit, everything you need to fit for around £100.00, the Hyper Pro is way more than double that for just the damper unit. I think Norman’s kit is such incredibly good value, and so well made, mine just fell on, with no adjustments necessary, I think if you wanted the Hyper Pro damper it would probably work with Norman’s bracket.

 

[Chris Launders]

Although I like this, .The problem that I face is that I need a guarantee of a fix to prevent another tank slapper, and I’m afraid that there are none..

I think I may have a solution to your dilemma about tank slappers, I built this bike 41 years ago and rode it almost constantly up until about ten years ago, covering an unknown mileage, but I did at least 10k on continental trips alone, it has finger light steering and the geometry is such that I think a tank slapper would be impossible. As a bonus a Vincent motor will fit with slight modification for the front exhaust pipe, possibly the rear carb and removal of the middle engine mount, I know as I dropped one in when it was a bare frame.

 

[timetraveller]

The Hyperpro will work with my kit. One owner wrote on here that he had changed from the Chinese one to a Hyperpro and it was so much stiffer that he had to drill a new hole for the actuating rod which was about half the distance which had been used with the original damper. The last time I checked the Hyperpros were about £320. I charge £125 for the whole kit including the damper.

I'm not sure that the Chinese dampers could be described as proportional or not. I have tested the ones which I supply by hand and at low speeds they push in and out relatively easily. Try to move them quickly and it is almost impossible. They are fully adjustable and even at slow speeds one can make them very difficult to move.

 

[MarBl]

The problem that I face is that I need a guarantee of a fix to prevent another tank slapper, and I’m afraid that there are none..

Attach a sidecar and crank up the friction damper.
You wont believe how much fun it is, to ride a sidecar rig.
And the twin engine is best suited to pull away the additional weight.
I had a R60 with Steib S350 for ten years and had so much fun with it, also in winter time.
You will enter a new world.

 

[Bill Thomas]

Don't believe him, Bob!
My first Tank slapper was in 1965 on a Vincent Outfit Twin.
I agree they are lots of fun but I should have run for the hills.

 

[Gary Gittleson]

Isn't there someone here who knows something about fluid dynamics? Intuition tells me that faster movements of the damper plunger, resulting in faster internal fluid movement will cause greater fluid resistance proportional to some power of the speed of movement, or something like that. TT's anecdotal observation seems to confirm that.