Author Topic: 35mm fork  (Read 31230 times)

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Offline von_Wanderlust

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Re: 35mm fork
« Reply #75 on: December 16, 2009, 05:10:46 AM »
Hey TG, was just reading some other threads and they mentioned the non-expensive cartridge emulators that are available from mikesxs.com for 35mm forks, i.e. works with 500 and 750 forks. Have you tried these? Paulages seems to have fitted a bunch to different bikes.
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Offline turboguzzi

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Re: 35mm fork
« Reply #76 on: December 16, 2009, 08:13:30 AM »
had them on other bikes, they work well on the road where when you hit sharp bumps normal forks have hydraulic lock

on the other hand, the return damping mechanism of the honda forks that works with a heavy washer as a one way valve is not affected by the emulators. I might give them a try but on the track sharp bumps are not the issue, i am looking for better controlled return damping

Offline MCRider

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Re: 35mm fork
« Reply #77 on: December 16, 2009, 08:17:33 AM »
had them on other bikes, they work well on the road where when you hit sharp bumps normal forks have hydraulic lock

on the other hand, the return damping mechanism of the honda forks that works with a heavy washer as a one way valve is not affected by the emulators. I might give them a try but on the track sharp bumps are not the issue, i am looking for better controlled return damping

RaceTech is pretty proud of their emulators especially for track work. More expensive than the ones on the XS site.  www.racetech.com
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
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Offline bwaller

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Re: 35mm fork
« Reply #78 on: December 16, 2009, 09:38:03 AM »
Good point TG.
I bought some replacement fork tubes from Forks by Frank for my race bike. They seem very good quality except for the "foot valve" inside near the base of the tubes. Franks installed an aluminum ring which doesn't much match the Honda piece, and will certainly affect damping. I was planning to use emulators but not sure if this aluminum ring may be a problem.  ???

Offline turboguzzi

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Re: 35mm fork
« Reply #79 on: December 16, 2009, 10:08:23 AM »
i am pretty sure that airtech will have good things to say about their emulators performance....  :)

my experience with them is that they mainly reduce harshness over sharp bumps (a very good thing, no doubt) while letting you use thicker oil (=stronger rebound damping) but the rebound damping remains pretty primitive and unadjustable. fidling with fork oil changes in the pits between session is no fun.

going to try the way of modern cartridges if time allows.

tg

 

Offline 754

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Re: 35mm fork
« Reply #80 on: December 16, 2009, 10:40:46 AM »
If the Franks tube has a snapring, you can put anything you want in there, ie fitting clearance, material, etc..
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Offline somesuch

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Re: 35mm fork
« Reply #81 on: December 17, 2009, 08:52:14 AM »
Good point TG.
I bought some replacement fork tubes from Forks by Frank for my race bike. They seem very good quality except for the "foot valve" inside near the base of the tubes. Franks installed an aluminum ring which doesn't much match the Honda piece, and will certainly affect damping. I was planning to use emulators but not sure if this aluminum ring may be a problem.  ???

I think it is just a way to secure the seal around the damper rod/hydraulic bottom out piece. The original Honda seal is fixed by the end of the fork tube being "rolled" while Frank uses a snap ring. The actual rebound damping is controlled by the two holes near the top of the damper rod, plus the leakage around the damper rod piston seal and the seal in the bottom of the fork tube that we are talking about.

Besides sealing around the damper rod, another function of the bottom of the fork tube, is to match the cone of the hydraulic bottom out, that aluminum piece that sits at the bottom of the fork....it basically goes into the bottom of the tube (and having a taper to it) starts restricting the oil flow in the last inch or so of the fork travel...effectively robbing you of that inch of suspension travel to prevent bottom outs. I think that most tuners get rid of that part and control the travel trough springs and damping...

I may not be up-to-date on the above, so before ditching hydraulic bottom out, I would ask someone like Lindeman to shed some light on this.

Offline turboguzzi

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Re: 35mm fork
« Reply #82 on: December 19, 2009, 08:22:14 PM »
some, what you say about the bottoming cones is true and indeed, on track, you hardly need them.

Offline DresdaHonda

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Re: 35mm fork
« Reply #83 on: September 12, 2010, 03:41:18 PM »
TG -are you happy with your RD350 fork ?

I have a pair of ceriani 35mm (from a lavada 750)
I´t´s a nice looking fork and easy to fit a drumbrake

Is there any mods Recommendations ?
I have a Paioli yokes with a 4cm offset -is that a good idea ?

Peter

Offline turboguzzi

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Re: 35mm fork
« Reply #84 on: September 13, 2010, 04:18:55 AM »
TG -are you happy with your RD350 fork ?

I have a pair of ceriani 35mm (from a lavada 750)
I´t´s a nice looking fork and easy to fit a drumbrake

Is there any mods Recommendations ?
I have a Paioli yokes with a 4cm offset -is that a good idea ?

Peter


didnt end up using the rd fork due to a bent tube, ceriani's sure sound nice though. I been running stock forks with welded damping holes and 1kg/mm springs and they are quite OK.

the offset will depend a lot on your frame's geometry and suspension set up in terms of ride height but 40mm sounds a bit much to me.

why dont you talk with dave degens directly? he might give you good tips

TG


Offline DresdaHonda

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Re: 35mm fork
« Reply #85 on: September 13, 2010, 05:48:35 AM »
My idea was that Dresda make the frames for road use, and you use the org. parts from Honda.
If you are making a racer you have to use a smaller offset ?? -for quicker steering
The Ceriani yokes is with a ca 7,2mm offset

Peter

Offline 754

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Re: 35mm fork
« Reply #86 on: September 13, 2010, 07:49:16 AM »
Turbo, you should check all fork tube, you could straighten that one..

Dresda,  some Ceriani forks for OEM, have offset axles. The ones you have, are they in the center, or offset?.. makes a difference in actual offset.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline turboguzzi

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Re: 35mm fork
« Reply #87 on: September 13, 2010, 12:15:25 PM »
Turbo, you should check all fork tube, you could straighten that one..


shame that you cant check that when buying from ebay ;)

got a refund though :)

can certainly straighten it, thing is that my cb500 is going to be pensioned at the end of this year, so I am stopping all my development plans and concentrating on my next racer build. had a long list of upgrades I wanted to do but that's it, time to move on.

TG


Offline DresdaHonda

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Re: 35mm fork
« Reply #88 on: September 13, 2010, 05:52:13 PM »
TG ..Move to what ???
Are you planing stopping racing???
-Or ar you gonna race a bigger class, with bigger forks?? ;D
Peter

Offline DresdaHonda

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Re: 35mm fork
« Reply #89 on: September 15, 2010, 04:16:41 PM »
To 754

The Ceriani yokes is a little out off center (2mm-3mm)
The Paioli yokes is in center

1.pic. Ceriani
2.pic. Paioli
 

Peter




Offline Phil

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Re: 35mm fork
« Reply #90 on: September 22, 2010, 11:55:59 AM »
Beware! I bought some new (pattern) fork tubes and then sent them to Maxton. They said the tubes were such poor quality they refused to use them! Send them the lowers only and they replace the rest with their super quality tubes, springs, cartridges, etc.. They are custom-made for you. They sort out the bushes. They sort out the spring-rates. Why settle for anything less?

Offline turboguzzi

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Re: 35mm fork
« Reply #91 on: September 22, 2010, 01:24:51 PM »
hei dresda

those triple clamps look like they have good offset, but best if you take some pics from above.

again how much offset you need depends on your frame geometry, suspension set up and of course how you like your steering to be.

I am not quitting, just moving to the open class. At 1.90m I have the feeling that I might be able to express myself better on a bigger bike.

details will follow :)

TG


Offline DresdaHonda

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Re: 35mm fork
« Reply #92 on: September 22, 2010, 02:18:30 PM »
Here some pics. from above
Pic.1 ceriani
pic.2 Paioli

Peter

Offline turboguzzi

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Re: 35mm fork
« Reply #93 on: September 22, 2010, 02:38:38 PM »
ok, clearer now

the paioli certainly have less offset, i.e. the distance between the center of the steering tube to the line that runs between the centers fo the fork legs. not surprising, most people here run paioli triple clamps.

The ceriani would be good i guess if your frame has around 30 degs of rake.