help with Marzocchi 45 mm shivers


9 replies to this topic
  • Kenaroo

Posted 06 January 2009 - 08:43 AM

#1

I'm currently trying to improve my Marzocchi Shiver 45's on my Beta 525. The fork action is acceptable except that the forks are blowing through the stroke on flat landings and "g" outs. .

The springs are .48's for my 210 lbs. 5 wt oil 90 mm from the top. I'm an 0-40 expert racing gps and hare scrambles here in Texas

The internal set-up is very basic. The base valve is shimmed heavy. The rebound shim stack is also heavy. There's no mid-valve, just a check valve set-up.
The base valve piston has very restrictive flow with only four 2 mm holes that feed the oil flow to the shim stack.
The Base Valve stack is as follows:

23 x 0.15
23 x 0.15
12 x 0.10 (cross over)
23 x 0.10
21 x 0.10
19 x 0.10
17 x 0.15
15 x 0.15
13 x 0.20

10 (base valve body)

The dampening valve (rebound check valve) is as follows:

22 x 0.10
22 x 0.10
22 x 0.10
22 x 0.10

Top of the valve has a check plate and light spring.


Could one of you suspension experts add their thoughts on this shim combination.

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  • mog

Posted 06 January 2009 - 02:39 PM

#2

where is your comp clicker? and what have you tried with it? and how did it feel if you adjusted it?

  • ztangoKLX

Posted 07 January 2009 - 03:08 PM

#3

Have you considered trying a heavier spring ?

  • harrperf

Posted 07 January 2009 - 03:43 PM

#4

I would yank the cross over and try that....where in texas are you?

  • Zac

Posted 10 January 2009 - 08:42 AM

#5

tell me the model year of your Beta


bye

Zac

  • Kenaroo

Posted 13 January 2009 - 01:08 PM

#6

I'm in Austin.

I have an 05 525 rr

running 2.5 wt oil 90 mm height.

Comp is 14 from full tight
rebound is 10 from full tight.

if I tighten her up any more I get killer arm pump and the bike doesn't handle.

with the current settings. she's real good through the trees and if I land perfect on the MX track (which doesn't happen very often).

problem is hard hits and g out.. it just "blows through the stroke and bottoms really hard.. no noise but I hear and feel the tire hit the fender/head pipe

tell me the model year of your Beta


bye

Zac



  • frezno

Posted 13 January 2009 - 03:32 PM

#7

running 2.5 wt oil 90 mm height.

the oil is way too thin. The zocchi asks for 7.5wt

  • Kenaroo

Posted 19 January 2009 - 08:41 AM

#8

the oil is way too thin. The zocchi asks for 7.5wt


that was it.. looked on the PVDesigns wiki to come up a mix of fluids to get the most consistant level equal to the Marzocchi oil.

made all the difference.. no more harsh bottoming.

started off at 100 mm from top (enduro setting) and ended up going with 90 mm from top (recommended for MX)

my settings are 7 clicks from soft on compression and 10 clicks from soft on the rebound. so I might re shim the compression to get a the clickers more to middle and make a tad more supple over the chop.

thanks for the feedback

  • frezno

Posted 20 January 2009 - 02:24 PM

#9

The zocchi asks for 7.5wt

that was it..
[...]
made all the difference.. no more harsh bottoming.

that's something Marzocchi victims have to be aware of.
You need 7.5wt oil. The reason is that the basevalve face shim OD is 21mm.
To cover the piston bores you'd need an OD of 22mm though.
That results in a free bleed.
Now, if you're using a thin oil, there's hardly any resistance and it's running through the remaining small openings like hell.
That's avoided by using the 7.5wt oil. For this thick oil it's much more difficult to pass the opening => you can't get a pig through an eye of a needle :thumbsup:

If you want to use 5wt oil you have to replace the 21 shims by 22s

  • MartyMOOSE

Posted 20 January 2009 - 03:01 PM

#10

Great info Frenzo :thumbsup: :p





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