New yoke, new yoke...

  • Thread starter Thread starter bob
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Tippie said:
Beautiful work there Bob.
You really need to adjust the offset for different tracks?
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Hi Tippie,
I won't be altering the offset for different tracks, the reason I've gone for adjustable yokes is simply so I can optimise the trail. Onced I've established the best setting I'll leave it where it is. At the moment I've got a lot of trail, this is because I've got a set of Spondon yokes of the type fitted to the Slater TT F500s. A 500 would be flat out for extended periods on the Island and apparently would get quite lively on some of the bumpier sections, hence the Spondon yokes. I have a feeling that an offset about halfway between stock and the Spondons will do the job but I didn't want to go the expense of having some trick yokes made only to find they didn't do the task properly. I had to have some yokes made for the 38mm forks I'm fitting so it seemed like a good opportunity to get the front end geometry sorted, the adjustability also allows me to experiment with dropping or raising the forks in the yokes.
Bob
 
By way of a follow up here's a pic of the finished Sports Motorcycles yokes. Glyn did a fantastic job and the new front end  including the yokes, the 38mm  FI forks , rotors , the chunky Lockheed master cylinder and the big Brembo FO9 calipers weighs precisely 1 kg less than the old 35mm forks, Spondon yokes, EBC rotors, FO5 calipers and Brembo master cylinder.  To keep the weight down we used a hollow Honda Hornet axle, alloy stem, Ti bolts etc etc. The discs are particularly nice and are machined from a billet of cast iron - a much nicer solution than using plate steel which is the more usual method.
Hopefully we'll be in a position to test after the weekend. I was hoping the new kit wouldn't weigh much more than the original set-up, to save a whole kilogramm was an unexpected bonus.

xxxforks-1.jpg


xxxyoke.jpg


xxxdisc-1.jpg
 
Looks realy nice.
Have you used the fork before? I bought a new FI 42 mm for my Mirage some 15 years ago. Very nice looking but i never got it to work realy well untill I had MH racing totaly rebuild it.

Who is suplying the discs??

Any chance of buying a 3d cad drawing for the yokes?

 
Hauge said:
Any chance of buying a 3d cad drawing for the yokes?
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:D :D :D Nice idea Thomas but probably not! The programming has only just been completed and I suspect Glyn would prefer you bought a set of his yokes rather than the programme...
I'm not sure how the forks will work, they feel very nice in the workshop although the adjustment is quite coarse. We'll see how they behave on the track, if I have any problems I'll get Maxton to work their magic on them.
The discs are manufactured in-house by Glyn and are part of the Sports Motorcycles newly launched product range, mainly aimed at Ducati TTF2 and TTF1 enthusiasts
 
Speaking of discs machined from solid - we used a bar of continuosly cast iron sliced into 1/2" sections to make the original 280mm discs. The swarf filled the bed of the lathe and would be worth quite a few bob these days. - Nice to see my FI forks being put to good use Bob - Regards - Phil
 

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bob said:
:D :D :D Nice idea Thomas but probably not! The programming has only just been completed and I suspect Glyn would prefer you bought a set of his yokes rather than the programme...
I'm not sure how the forks will work, they feel very nice in the workshop although the adjustment is quite coarse. We'll see how they behave on the track, if I have any problems I'll get Maxton to work their magic on them.
The discs are manufactured in-house by Glyn and are part of the Sports Motorcycles newly launched product range, mainly aimed at Ducati TTF2 and TTF1 enthusiasts
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Thats what I thought.
I prefer to buy parts from local mecanic work shop due to "tax regulations"...
I'll give Glyn a call. Cant be that much trouble chaning the fork for 35mm tubes.
Are you using the same with as standard?

 
Bob, currently building a project Monty and wouldn't mind using a similar set up as this on it.
Can you tell me where to get a set of these forks and also Glyn's contact details.
Glenn
 
Dellortoman said:
For finer adjustment you could make up a different set of eccentrics with less offset. That's assuming you don't have too many eccentrics hanging around already.
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Cam,
The yokes come with three alternative pairs of inserts, one set has a concentric hole and the other set has a more extreme eccentric than the one in the pic. Each insert has a pin which locates in the groove in the main body of the yoke[you can see it in the pic] which effectively indexes the insert when you turn it through 180 degrees thus providing  5 potential offsets.

Thomas, the yokes are available for 35mm forks, and Glyn offers a couple of different widths, the stem is also adjustable for length- once you've adjusted it to suit your bearings you simply bond the adjustable ends to the stem . If you use a glue such as Loctite 638 you can unbond it a bit of heat should you want to transfer the yokes to a different bike.

Phil, I don't think I've ever seen a technical development discussed on this forum which you haven't previously experimented with two decades earlier!
:D :D :D

Geoff, The forks are quite rare and were fitted to Ducati 750 F1s c1988, some high end Guzzis and I've also seen them on MVs and Bimotas. You could probably end up with a superior set of forks if you simply get some 38mm Cerianis and send them to Maxton for their cartridge conversion. I opted for the F!s because Keith [having acquired them from Phil] let me have them for a very reasonable price. :D They come up for sale occasionally but you could end up parting with a grand for a set because of the Ducati connection. The big plus for me is the ability to access the damping adjustment so easily, on the Maxton conversions you have to remove the wheel to fiddle with the compression damping, which is a pain in the arse.
 
Guzzi used similar forks on Daytona (carburator version) and 1100 Sport. They came for 270? a pair to me... One side adjustable rebound, one side adjustable compression, both accessable from the top. Unfortunately no preload adjustment... Only issue is that their caliper holder is for 40mm distance calipers and they are set for 320mm discs. So - either make some new discs or some caliper adapters.
 
Laverdalothar said:
Guzzi used similar forks on Daytona (carburator version) and 1100 Sport. They came for 270? a pair to me... One side adjustable rebound, one side adjustable compression, both accessable from the top. Unfortunately no preload adjustment... Only issue is that their caliper holder is for 40mm distance calipers and they are set for 320mm discs. So - either make some new discs or some caliper adapters.
Click to expand...

Where the Guzzi forks made by marzocci ?


Anyway, I talked do Glyn and I'm getting a set of yokes from him. Nice bloke and very good price. We had a nice long chat since i have a bunch of ducatis to. It will not surprise me if i get a tt2 replica kit from him sooner or later...
I'll have him to make some discs as well as soon as I have decided which boltpattern and offset to use. I have a set of Dymags with Yamaha bolt pattern, a set of new Campagnolo replicas without hubs and a set of Astralites with undefined hubs.
Would be good if I could swap between different wheels.
 
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