FF: Forks Brampton forks

[Peter Holmes]

I don't think it is quite that simple Norman, the component that you are referring to as the bottom link does not exist on the Brampton fork, it forms part of the entire tubular construction, I presume the bottom, middle and top forgings of the forks are all brazed together with the fork tubes, unless you had contemplated doing that anyway, big job, not really comparable to the Girdraulic fork

There have been several attempts at achieving a decent coil over conversion, starting with the Woodhead Munroe conversion, probably when Brampton forks were still being fitted to bikes from new. John Renwick did one for Harvey Bowden, and I don't think he used the bottom coil spring bracket that the original coil spring attaches to, but maybe just bolstered up the original headlamp bracket, I might email Harvey and see if he send me over some decent photos, and an opinion on how well it all worked, I have a feeling Harvey was not overly impressed with the ride quality.

 

[vibrac]

I dont think using just the headlamp bracket gives enough strength here the links also gain strength from the original spring support and leave it returnable to Standard
NB I am considering extending the links to give support to the brake beam those alloy racing brake plates need some firmness adding

 

[timetraveller]

OK Peter and Tim. All useful info. Vincent's photo (posting#4) and Tim's above are very useful so I now can see that there is no lower link. The solution that Tim has looks like it could be fabricated easily enough and not offend those who prefer to see pieces left unmolested. However, I thought that I had read that AVO were not prepared to be involved but I have not been keeping a watch on this subject. I have just been out to my shed and measured the diameter of one of the rear coil overs from AVO (one of five to go out with the new batch of JE stems) and the diameter is about 68mm. Even if a reduced gauge of wire could be used at the front then that diameter would not reduce by much and I doubt that there is space inside the top of the forks to take something that diameter. So someone has to source a suspension unit before much progress could be made. Is there something off a scooter or small bike which might be suitable?

 

[Peter Holmes]

Alyn Vincent had got involved in this project before Covid struck, understandably for now it seems to have stalled, but I think his intention was to use an IKON damper as the basis of his conversion, IKON is virtually the old Vincent Koni damper, adapted to take a coil over spring.

 

[timetraveller]

I think that the Koni had the same damping on compression and extension so, if that is correct, it would be nice to use something a little more sophisticated

 

[MarBl]

I offered to do some design work and get a price for getting some new ones made by CNC machining. There was no interest.

I'd be very interested in a new FF1 with wider brackets.
I gathered some information about modern damper alternatives and almost all established producers can provide coil overs with appropriate length. But all have wide upper lugs made of aluminum.
Now whilst I would not fit a coil over into my Girdraulic (which would be of too large a diameter in most cases anyway), I'd very much like to install the modern adjustable damper only, that would fit in most cases (given a wider upper bracket), omitting the spring.

 

[MarBl]

IKON is virtually the old Vincent Koni damper

I think that the Koni had the same damping on compression and extension

Koni has stronger and adjustable damping on extension.

The new IKON is different, not adjustable (only via different valves) and as far as I know symmetric in compression and extension. The latter I could not check yet, as I did not receive mine yet.

 

[Vincent Brake]

I am a lucky kid here...
Done already some 16.000km with it. Oh dont forget to take out the friction dampers, put in some oily Nylon.

It realy rides like a series A.

Just done 3000km of hairpins in Italy Motogiro.

Good luck guys.

 

[timetraveller]

MarBI, if I understand correctly you would like an adjustable damper to replace to original Vincent or Armstrong damper. AVO provide such a damper and I recommend it is fitted to all the JE steering stems I provide. It does fit into the standard FF1. This damper was developed by one of the users of this forum (hadronuk) in conjunction with AVO. The price is £168 from AVO and if they will not supply you I can get one for you and send it. The AVO does fit into the standard Vincent space but on some bikes one has to remove metal from the rear of the upper link as was done on series Ds

 

[MarBl]

AVO provide such a damper and I recommend it is fitted to all the JE steering stems I provide

Well yes, I got one from you along with the JE Mod , but it turned out to be way too stiff for my liking, so I am looking for alternatives. I already ordered an IKON along with a set of valves, but I would prefer a modern adjustable damper to get the optimum out of that very limited fork travel.
And the JE Mod will get some needle bearings this winter.