fork brace

  • Thread starter Thread starter Paddy
  • Start date Start date
Strangely the problem i had was the clamps clamping the legs top the stanchions, you could remove the centre section completely and the forks were locked.  Yes you could slacken off the clamps but then you were not really bracing the  legs if you see what i mean. The whole thing seemed a compromise and an ugly one at at that hence me wondering about incorporating the brace into the mudguard arch..
 
Paddy said:
at that hence me wondering about incorporating the brace into the mudguard arch..
Click to expand...

makes a lot of sence, but won't be easy. I think on the M1R, this should be very easy to do, on the 38mm Marzocchi, it is hard to find a good solutions using the mudguard mounting points.

The Telefix I have works good, but I agree if you overtighten them, they block movement. It is not necessary though in my opinion to tighten them to the full. What I do to make them work is leave the center screws open, mount them on the fork until they block and turn the screw slightly backwards until the do not block the fork anymore. they still sit very tight. then I do relax the complete front end as described several times fastening the center screws one after the other with the holding the front brake engaged and push the bike down several times in between. my bikes fork works as good as it can with the given technology in it with that method.

HTH
 
IMHO a lot of the problem is because the surfaces being clamped onto are as-cast and thus not any particular size and is not particularly round or parallel.  I reckon a light skim over the top of the fork slider where you clamp it would help a lot.
 
blab said:
Setting up a fork slider in a lathe to skim it sounds pretty hard to me.
Click to expand...

  Pretty straightforward. Machine a mandrel, slide the leg onto the mandrel and apply light pressure to the bottom of the fork using a floating centre to lock it to the headstock. Doing it this way ensures the O/D of the fork leg is concentric with the bore for the stanchion.


  Keith
 
Not for a machinist. Hold the bottom in a 4 jaw and make a bush to support the top with the tailstock.  Might take you half an hour to set the first one up and five minutes for the second.
 
breganzane said:
Not for a machinist. Hold the bottom in a 4 jaw and make a bush to support the top with the tailstock.  Might take you half an hour to set the first one up and five minutes for the second.
Click to expand...

No way to check the bore is concentric all the way down the tube doing it this way, top will be concentric to the tailstock but the bottom could be jiving around a bit in the four jaw, machine it off a mandrel and it sets itself up concentric and parallel automatically. Not much in it if only turning the top couple of inches to mount a brace granted but I recon if you are going to do it you may as well do what you can to get it done right.  ;)


  Keith
 
Morning all,

As a fellow machinist Keith has got the answer spot on, it is also quite easy to do.


Andy
 
I take what you are saying but the wall thickness is only 8mm now and they tend to collapse, not sure i would want to turn much off the OD. Soft as butter as well.
 
laverdakeith said:
No way to check the bore is concentric all the way down the tube doing it this way, top will be concentric to the tailstock but the bottom could be jiving around a bit in the four jaw,
  Keith
Click to expand...

Well I wrote it off the top of my head while preparing dinner and prior to your response landing.  The point was it's not hard.  It's a long part and a short cut at the known end in either case, and I assumed some knowledge on the part of the operator.  To similarly nitpick, with the top in a mandrel and the bottom in a live centre, how do you prove it's actually concentric to the bottom of the fork tube bore?  It's enclosed so you can't measure it, even a full-length mandrel will be easily pulled to one side by the tailstock over that distance, you are assuming they are concentric, while in reality it's highly likely the fork tube bore and bottom hole/counterbore were done in different setups and could be misaligned.  If you're going to split hairs, you might as well do it properly.  :D
 
Dunno about Marzocchis, but with Cerianis the whole "plug" at the bottom of the fork is only interference fitted, knocks out easily so you can support the slider and maintain concentricity between top and bottom. Been discussed here before.

Ken
 
breganzane said:
Well I wrote it off the top of my head while preparing dinner and prior to your response landing.  The point was it's not hard.  It's a long part and a short cut at the known end in either case, and I assumed some knowledge on the part of the operator.  To similarly nitpick, with the top in a mandrel and the bottom in a live centre, how do you prove it's actually concentric to the bottom of the fork tube bore?  It's enclosed so you can't measure it, even a full-length mandrel will be easily pulled to one side by the tailstock over that distance, you are assuming they are concentric, while in reality it's highly likely the fork tube bore and bottom hole/counterbore were done in different setups and could be misaligned.  If you're going to split hairs, you might as well do it properly.  :D
Click to expand...

  That's why I stipulated a floating centre on the other end, not using the counterbore. Back atcha baldy  :-*
Hope dinner was nice.


    Keith.
 
I'm not taking sides here :)
A good fit in the bearing over 2-3 inch would be ample so a mandrel turned in situ would be fine. Your problem, or rather my problem would be  holding the other end which will be all over the place given just looking down the fork leg i can see the bore is no where near concentric with the hole in the end or the outer wall. If you cant use a running centre you may have a problem getting drive ( i dont have a floating centre). I think we may be over engineering the problem here given we don't even know the top where a brace clamps is not true in the first place. The top of the fork leg is bored to take the seals and the first 3 inch of bearing surface is undercut so its reasonable to assume the two were machined together and that they are in fact concentric with the outside unless there is anything glaringly obvious to say different.
the obvious answer here is to measure the  max travel and place a second top  yoke between the bottom yoke and the top of the fork leg....:D

while i am messing around with this......just getting the bits ready to send off to the sprayer and i'm thinking, do i stand any chance of finding a S/S front mudguard for one of these Jota's ?
 
Got me thinking now. I just looked through Keiths flicker link at the orange Jota's at the start and one  has a S/S font mudguard which looks remarkable similar to the Darmah ones and even more so the Darmah SS ones. These use all 8 mounting studs so could be stiffer in themselves anyway. I have at least 10 of these in stock so thats the next job.......see if the fork spacing is the same as Ducati. :) ...............just thinking out loud :)
 
I had a Ducati stainless guard on my Mirage, it worked but looked like it was a Ducati guard stuck on a Laverda if you get my drift. Looked a bit naff.......
 
I can see that would be the case with a SD mudguard but a SSD might work. I need to find a good picture of a Jota one. Of course if i can pick one up for reasonable money i will just look for the proper thing.
 
Talking of swapping the front end  :D are all M1R legs the same  ? Ie will a Paso with 16" wheels have the same legs as a Lav ie: Do they just allow for different dia wheels in the mudguard shape ? Obviously the stanchions are different.
 
Paddy said:
Talking of swapping the front end  :D are all M1R legs the same  ? Ie will a Paso with 16" wheels have the same legs as a Lav ie: Do they just allow for different dia wheels in the mudguard shape ? Obviously the stanchions are different.
Click to expand...

No.

They cater for different disc diameters and disc offset as well as for caliper mounts, depending on where they were first fitted.

Paso has 280mm discs for P08 calipers, Laverda 300mm also for P08, Duc 851 and Guzzi 320mm with P32/32 or P30/34.

piet
 
You must log in or register to reply here.
Back
Top