in stead of valve lift drilling holes in cartridge

georgieboy · Apr 11, 2003

Oke guys, let me try this one more time. Only i start this thread from a different angle.
To create a plush fork you tuners work with a free lift at the midvalve compression stack to provide a easy flow for the oil.
What do you think of the genius thing marzocchi did by using zero valvelift and drilling holes in the cartridge rod at progressive distances to create that plushness. So going deeper in the stroke closes more holes and thus creating more pressure on the valve stack/more damping.
Is above correct in any way, or do i miss something completely.
I just want to understand how my forks work compared to the japanese ones.
When above is true, why don't everybody use this kind of progressive free oil flow tactic to create that plush fork.

marcusgunby · Apr 11, 2003

I would love to see this type of fork apart, from what i hear the original was the best ,and the later ones were not good.You can achieve free bleed using a bleed shim on the base valve.I rode a set of KTM WP SXS forks set up like this(with a bleed shim), and they were some of the best forks ive ridden.

Vic · Apr 12, 2003

Originally posted by marcusgunby
You can achieve free bleed using a bleed shim on the base valve.

Marcus, what would be the typical thickness for such a shim?

marcusgunby · Apr 12, 2003

0.1mm would be as much as you would want to go-any more and you will need to run a gold valve type stack to give sufficient damping.One thing is a smaller o/d bleed shim actually gives less bleed as the stack bends over it and closes up the bleed gap.
eg
16.1 bleed shim
24.1(normal stack)
gives less bleed than
20.1
24.1(normal stack)

georgieboy · Apr 12, 2003

I understand you guys want to talk about shims, but considering the holes. What wld be yr idea the diameter of the holes must be to have the same effect as a bleed shim. 0.3mm or less? I now drilled 4 holes at various distances. I used 0.3mm drills. Wld you guys advise me going maybe to 0.2mm holes, or 0.1mm?
I want less dive while breaking.
Can you really lock a fork up by having no free oil flow at all. So no free valve lift and no bleedshims and no holes??

marcusgunby · Apr 12, 2003

I wish i could help you but i have no experience of the system.How about filling the higher holes but leaving the lower ones??

Vic · Apr 12, 2003

Thanks, Marcus.

bclapham · Apr 12, 2003

i am confused here. so on the base valve from the bottom up we would have, 1. clamp shim. 2 stack. 3. a 16-20 (.1) bleed shim 4. piston 5 rebound check plate. so the base valve compression stack would have a kind of permenant lift of 0.1mm. wouldnt this mess up the rebound stroke (ie. cause bleed and thus soften/speed up the rebound, or would the 24.1 shim bend back over the piston quickly enough to seal those ports on the rebound stroke? i am off home to look at a base valve!

i actually though about something similar- to use a single bleed shim to kind of set a permenant type lift on a midvalve- i tried to explain this on that suspension network but no one seemed to understand me, LOL!

when we are done on this, i am gonna ask you about them passive bleed shims!:p

marcusgunby · Apr 12, 2003

bruce you have it correct on the stack build,think how the rebound damping is made, the rebound piston will be affected by the midvalve not sealing-on the base valve the returning oil just bypasses the comp stack.

On the midvalve lift, its better to have a spring loaded type setup to close the mid, it will make it more relaible.Ive heard of PC setting a very low lift(0.2mm) and not using any kind of spring but at real low lifts the flow of oil will close the lift gap.I have used this setup and it worked.Any more than 0.2mm(how many thous is that BTW;) needs a spring to return the stack.

marcusgunby · Apr 12, 2003

On the question of locking a fork-a cr125 fork with the comp turned all the way in, is the set up you describe-it has no lift-no bleed but will still go through the travel.

bclapham · Apr 12, 2003

Originally posted by marcusgunby
Any more than 0.2mm(how many thous is that BTW;)

half the number of thous that i didnt ask to have taken off my cylinder head when i really asked for 0.5mm :confused: :thumb:

DEANSFASTWAY · Apr 13, 2003

Georgieboy, In the past on woodsie bikes weve slotted the cartridges To create a bleed but we must remember that it also affects rebound action, not very good for hard core MX . Ive always wondered about the Original MZ forks With drilled (actually Slits ) in the cartridge but these forks were LS rebound RS comp . On those we were actually trying to weld up the slits and make them more tapered but we scrapped it when the Cartridge kits came out from Malcolm Smith . We installed a couple and they seemed to work well . I havent seen but only a few late 02 03 MZ setups . I thought about trying to make a bleed on cartrige top and maybe using a bit stiffer top out springs but havent the time to invest right now . Let us know what you find out . CHEERS DEAN

georgieboy · Apr 13, 2003

Marcus, i am considering closing the lower holes to see how things go.(remember we are talking about a conventional fork here)
Dean, originally my fork came with a slot of 10cm on the comp leg. I welded it close with silver solder, and drilled 4 holes at progressive intervals to get some progressive compression. The holes are maybe to big and making them smaller is something i am thinking about. What did the malcolm cartridges look like?

MikeS · Apr 14, 2003

Georgie

Look at a C-Cycle advertisement on their site or in a publication as the show the cartridges. Kits are Kayaba and allow seperate rebound and compression on both legs.

The proper holes that some guys use are 9/64"at 4 holes or 5/64 at 5 holes. These work OK but require the compression to be cranked stiff for any serious MX riding.

I had a set re done by a tuner (Rob Mann). He closed up the slot and added a .090" hole in the very bottom. He changed the valve stack. I never knew what was stock so I can not tell what was added. These forks work very very good. We run offroad (harescrambles GNCC). B Level rider. We run moderate MX and Arenacross. 60 ft front wheel flat landings hurt even with Compression cranked in. Junior rode a Stock RM125 and a 03 KTM125SX and found his set up for offroad better.

Goodluck on your quest

georgieboy · Apr 15, 2003

Thnks MikeS, for yr answer. 5/64" what is that in metric. I have to get my calculator for that. Can't do by mind.
Thnks guys for all the input, i have a rest now and start thinking things over.

in stead of valve lift drilling holes in cartridge

georgieboy

marcusgunby

Vic

***** freak.

marcusgunby

georgieboy

marcusgunby

Vic

***** freak.

bclapham

marcusgunby

marcusgunby

bclapham

DEANSFASTWAY

georgieboy

MikeS

georgieboy

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in stead of valve lift drilling holes in cartridge

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