Animated fork diagram

Questions and comments about converting to beefier forks..
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bradf
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Animated fork diagram

Post by bradf »

here is the link. I don't know the legal stuff controlling this so Vince, do with this as you need to do if it is ill-eagle.

http://homepage.sunrise.ch/homepage/mza ... hrgru.html

here is the translation:

The feather/spring The feather/spring is there to lead back the chassis again and again into the initial state. If the motorcycle drives over a stone, the chassis bounces, afterwards the feather/spring is responsible to push the wheel again back. If the motorcycle drives over a falling stage, the chassis releases, afterwards the gewichtskraft of the motorcycle is larger than the spring action, so that the chassis bounces again to gewichtskraft and spring action are equivalent large. The spring temper indicates, how quickly a chassis reacts. If the feather/spring is too hard, the chassis reacts too fast and can easily the soil contact lose, is too soft it, is not too slow the chassis so that the motorcycle not sufficient fast on coming obstacles ready is. A heavier driver needs a harder feather/spring, so that it has sufficient strength the larger mass sufficient fast back to approach. With a lighter driver accordingly in reverse. A chassis, which was realized only with feathers/springs, would not be suited, since the energy of an impact was not swallowed, but only in the feather/spring buffered would be. This stored energy was passed on to the motorcycle. A motorcycle without Stossaempfer would hop like a rubber ball. The absorption The absorption brakes chassis movements. Slow movements are braked hardly, snap for it the more violently. Surface irregularities are swallowed in the absorber (not in the feather/spring). Absorbers are developed usually as follows: A piston presses oil by small drillings, which causes a speed-dependent resistance. Bouncing is more weakly absorbed than a releasing, so that an impact is fast caught, without much will transfer to the driver. This is realized by means of valves, which drillings differently large depending upon river direction of the oil release. With increasing speed of the oil however the resistance grows squarely. I.e. at double bouncing speed the absorbing strength becomes four times large so. Cheap motorcycles use such absorptions. This Toeffs feels like schaukelpferde, since the slow chassis movements are absorbed only insufficiently. A hard impact is transferred trozdem brutally to the driver, because fast chassis movements are too strongly braked. Modern absorbers exhibit therefore additional drillings, which are locked with the Shims. This Shims is from spring steel and with increasing oil pressure of the locked drillings is away-bent, so that a larger cross section is to the oil flow at the disposal. The Shims into a pile combined which one from different Shims arrange can. The Shims differs in material thickness and diameter. With this composition one can stop the absorption into that differently speed ranges. One can stop the basic adjustment from the outside with a screwdriver, one moved thereby a needle valve, which more or less locks a drilling. This is separate for releasing (traction phase) and bouncing (compression phase). One speaks here of the basic absorption or of the slow absorption. Over the Shims the fast absorption is stopped.


The Kayaba fork is a Upside down fork with a cartridge absorber. Upside down bedeuted that itself the outside, thicker fork pipe above at the fork bridge finds during the internal pipe down is. With a conventional fork this straight turned around. Both designs have their pro and cons. Many more crucially on the handling the internal structure is or if necessary still the diameter. A large diameter of the gleitrohre (internal pipe) results in a verwindungssteiffere fork however the responsing mode becomes worse, since the larger seals cause also more friction. Cartridge absorber bedeuted, which is in the internal fork a separate piston cylinder system, the Kartouche or absorber cartridge. The GIF animation further down shows, how the components move and how the oil flows. Dark grey bedeuted: Area with erhoetem pressure. For the compression phase (absorption when bouncing) the soil valve is responsible: If the piston in-moves into the cartridge, the area over the piston becomes larger, therefore oil from down must flow upward by the piston valve. There the check valve opens, so that the piston valve does not offer a resistance to the oil flow. The piston rod driving into the cartridge displaces oil in the cylinder, thus the pressure in the whole cartridge rises. The oil escapes now by the soil valve from the cartridge, which in this river direction resistance offers and absorbs so the bouncing movement. The oil flows through with slow movements only beside the adjusting screw. With faster movements rises the pressure in the cartridge, which presses the Shims of the soil valve downward, which releases additional cross section for the oil flow. For the traction phase (absorption when releasing) the piston valve is responsible: The piston moves in the cartridge upward. The piston rod driving from the cartridge releases again volumes. The oil flows by the opened check valve of the soil valve into the cartridge. The area over the piston becomes smaller, thus the pressure over the piston rises, so that the oil flows by a drilling the piston rod highly. The adjusting screw of the traction phase adjusts this river, by determining, how far a pipe led inside the piston rod releases the drilling with the piston valve. With faster strokes the higher pressure presses the Shims of the piston valve in the top of the cartridge additionally downward, so that additionally oil can flow into the area underneath the piston.


In principle all area-haven-suited forks are developed similarly, denoch give it differences. Ability pressure and traction phase to be adjusted above, but only per one per cross-beam, then the soil valve does not have drilling with needle valve. With the cross-beam where the compression phase can be stopped, flows the drilling, which leads into the piston rod, into the area underneath the piston valve. Newer forks have a closed cartridge: It is separate the oil in and outside of the cartridge which has the advantage that air in the cross-beam cannot arrive into the cartridge and so a constant absorption is guaranteed. Marzzochi builds a fork, which do not only absorb speed-dependently, but also track-dependent: Lateral drillings in the cartridge are more or less released by the piston, so that the absorption is more strongly effective in the bounced range than in the released.
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strider80
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Post by strider80 »

Wow, the animation makes it much clearer now!
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Indawoods
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Last edited by Indawoods on 06:48 pm Nov 21 2006, edited 2 times in total.
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Post by bradf »

If a picture is worth a thousand words then an animated pic is worth a bazillion words. This diagram shows a CV and not a MV stack. So CM, here ya go! The lift is the amount you see the plate moving up.
'04 220 w/'01 KX250 USD forks, '02 RM125 Showa shock, Rekluse EXP 3.0, LHRB & all RB'd
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Post by Colorado Mike »

Awesome Brad , you da man. I just might get a handle on this stuff yet.

Thanks very much!
Mike

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strider80
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Post by strider80 »

Where would a bladder be?
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Post by bradf »

The bladder covers the entire blue cartridge you see going up and own and up and down and up and...well you know. Any ways, the bladder clamps on the cartridge at the BV end by 3 springs and also up just below the main spring base where there is a plastic collar and 3 more springs. The idea was to help eliminate bottoming with the bladder. Oil would be forced through the bladder up to the restrictive barrier (plastic and a machined washer below the spring, actually the springs base) and be restricted by the huge temporary force on the spring against the RB. This would be for hard landings in SX and MX. It did work but it created a huge mid-stroke spike that was despised by everyone. It was an engineering HUTA (head up the ass) by Mr. Kayaba.

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Post by canyncarvr »

CM: Youre saying all that makes fine sense to 'ye? Gewichtskrafts, area-haven-suited forks, and river directions of oil releases?

Heck...if I'd known that would make perfect sense to 'ya, I would have 'splained it all a long time ago!!

Gott'a love engineering HUTAs!!

Speaking of which..this definition of a USD fork:
..fork pipe above at the fork bridge finds during the internal pipe down is.
..was that written by Mr. Kayaba? :wink:

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Post by Colorado Mike »

CC ya gotta unterstain, I utes to own a CZ400. The manual for that was translated from Czechoslovakian and was hilarious even to the non-biking pubic.

Sides that, I used to live in Doucheland. Learned all the Gemurman I needed to know.

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