Thursday 21 February 2013

Marzocchi set up guide: understanding the basics

Break-in Period
Some forks may require 5-10 hours of use before the fork fully breaks-in. After the bushings, seals, and other parts have matched to each other, the fork will move smoother. The tight tolerances make the fork last longer and work better.

Sag
Sag refers to how much the fork compresses when the rider is in the normal riding position. Marzocchi recommends 10-20% of XC travel and 20-30% of DH travel in sag to provide the best overall ride. The easiest way to measure sag is to put a zip tie around the stanchion and then measure how much the fork compresses when the rider is in the normal riding position. Keep in mind that the normal riding position on a DH bike may not be correct on level ground. Refer to the following charts for reference.

Spring Preload
Spring preload can be done with the external adjusters on top of the fork. Preloading the springs will compress them slightly and increase the initial force needed to compress the spring. Bomber forks can use the maximum amount of preload from the adjuster and the fork will still get full travel. Spring preload is used to fine tune the spring rate to adjust for the proper sag measurement. Minimal spring preload is recommended for better performance and longer working life of the springs, so it is better to change to a stiffer spring rate than to add significant preload (10+ turns.)

Coil Spring
The spring rate of a coil spring refers to the amount of force needed to compress the springs in the fork. Marzocchi offers several different spring kits to coordinate rider weight and riding conditions. All springs are made from the highest quality chromium silicon (CRSI) or Titanium. Marzocchi use linear wound springs. Some older models used Pro-Wind springs which are progressively wound (coil wind gets closer together at one end.) Dual Rate kits use two compression springs per side. Put the longer compression spring on the bottom and then put the short spring on top to later ease disassembly. 

Air Spring
Air spring rate is the amount of air pressure that is in the fork. Marzocchi forks come pressurized for the average rider at about 35psi/3.0bar. Air pressure can be infinitely adjusted using a shock pump to fit rider preference. Be sure to use a pump that can accurately gauge air pressure in the adjustment range. Full air pressure charts can be found via www.marzocchi.com these recommendations should be used as a starting point. Air pressure may need to be adjusted according to riding style, frame design, terrain, and/or personal preferences and may vary between pump brands.

Rebound Damping
Rebound damping controls the rate in which the fork is able to extend. Most models all feature some type of external adjustable rebound damping. Rebound damping should be set fairly fast, but without causing a sudden, harsh force back to the rider. This will allow the fork to comfortably extend to full travel as soon as possible after impact.It is a good idea to get a feel for how the different rebound adjustments affect the fork. On forks that have external adjusters, try turning the adjuster all the way counter-clockwise to the fastest rebound setting and then quickly compress and release the suspension several times. Next test the fork with the adjuster turned all the way clockwise and then somewhere in between. This will demonstrate the differences between damping settings.
Older models using the SSV Non-Adjustable System can change their rebound damping with oil viscosities. Stock oil is 7.5 weight, so changing to a lighter oil (Example: 5 wt.) will increase the rebound speed. Heavier riders using stiffer springs may want to adjust their rebound speed with heavier weight oil. Be sure only to use a high quality motorcycle fork oil like Marzocchi’s Factory Fork Oil.
 
Compression Damping
Compression damping is the oil flow resistance felt when compressing the fork. Compression damping is categorized in two ways: low speed compression and high speed compression. Low speed compression refers to when the fork is compressed slowly and gradually, for example during rolling impacts and rounded bumps. High-speed compression refers to the resistance felt during multiple, hard impacts and square-edged bumps. It is better to be conservative while setting the compression damping because the spring offers resistance to compression as well. Too much compression damping creates a harsh ride because the suspension cannot compress rapidly enough to absorb large impacts. Compression damping is not a substitute for proper spring rate and should not be adjusted until the fork has the proper spring setup for the rider.
RC3 models feature both high and low speed compression damping. Turning the adjuster to the '+' or hard will increase the low speed compression damping and turning to the '-' or soft increases the high speed compression damping with both damping curves crossing in the middle.
Forks that do not have an external compression adjuster can modify their compression damping by changing the oil viscosity. Although most riders will be happy with the stock compression settings, some riders may prefer a different weight oil to coordinate with rider weight and/or spring setup. Keep in mind that changing the oil viscosity will change the entire damping range and will affect rebound as well. 

Set up: Understanding the Marzocchi 888

The 888 has a lot of adjustments, here is a guide to what everything does. Every adjustment is relative to the spring rate, so get the spring correct and work from here.

Spring options

Titanium k=4.4 " 5141956 - soft k=5,5" 5141918 - med k=6.5" 5141957 - hard k=7.7" 5141958 -  x hard
Steel k=4.4 " 5141959 - soft k=5,4" 5141923 - med k=6.5" 5141960 - hard k=7.7" 5141961 – x hard
preload
Spring Preload
Spring preload can be done with the external RH adjuster on top of the fork. Preloading the spring will compress them slightly and increase the initial force needed to compress the spring. Marzocchi forks can use the maximum amount of preload from the adjuster and the fork will still get full travel. Spring preload is used to fine-tune the spring rate to adjust for the proper sag measurement. Minimal spring preload is recommended for better performance and longer working life of the springs, so it is better to change to a stiffer spring rate than to add significant preload (10+ turns.)
Sag refers to how much the fork compresses when the rider is in the normal riding position. Marzocchi recommends 20-30% of DH travel in sag to provide the best overall ride. The easiest way to measure sag is to put a zip tie around the stanchion and then measure how much the fork compresses when the rider is in the normal riding position. Keep in mind that the normal riding position on a DH bike may not be correct on level ground.


rebound


Rebound Damping
Rebound damping controls the rate in which the fork is able to extend. All Marzocchi forks have adjustable rebound damping. Rebound damping should be set fairly fast, but without causing a sudden, harsh force back to the rider. This will allow the fork to comfortably extend to full travel as soon as possible after impact.
The 888’s damping adjuster located on the top of the left hand leg and is anodized red. Turning the adjuster clockwise will slow the rebound speed and therefore turning the adjuster counter-clockwise will speed up rebound.
It is a good idea to get a feel for how the different rebound adjustments affect the fork. Try turning the adjuster all the way counter-clockwise to the fastest rebound setting and then quickly compress and release the suspension several times. Next test the fork with the adjuster turned all the way clockwise and then somewhere in between. This will demonstrate the differences between damping settings.
compression
Compression Damping
Compression damping is the oil flow resistance felt when compressing the fork. Compression damping is categorized in two ways: low speed compression and high-speed compression. Low speed compression refers to when the fork is compressed slowly and gradually, for example during rolling impacts and rounded bumps. High-speed compression refers to the resistance felt during multiple, hard impacts and square-edged bumps.
Too much compression damping creates a harsh ride because the suspension cannot compress rapidly enough to absorb large impacts. Compression damping is not a substitute for proper spring rate and should not be adjusted until the fork has the proper spring set-up for the rider.
Low speed damping is typically used to dial out excessive fork dive or rider induced movement. High speed is typically used to make the forks action more progressive and resist bottoming out.
The compression adjuster on the 888 is located at the base of the LH leg. The RC3 compression adjuster will affect both high and low speed damping, simply put if you set the adjuster all the way to “+” it will give you maximum low speed damping, set the adjuster all the way to “-“ will give you maximum high speed damping.
Both high and low speed damping curves cross in the middle so the adjusters neutral position is in the middle (count the clicks/ turns). Adjusting out from the middle with give you a varying combination of both high and low speed damping, so in theory you have all the combinations of damping you would normally have in two separate adjusters, but in one easy-to-use adjuster.
***graph for visualization purposes only



Volume adj 
Volume Adjust
Volume Adjust is a simple and effective way to control the second half of the compression stroke and is located underneath the rebound adjuter on the top of the LH leg.
The VA works via lowering and raising the top of natural air chamber inside the fork. This gives the same effect as raising or lowering the oil volume; a tuning ‘trick’ often used to make the compression stoke more linear or progressive. The VA offers this with an easy to use external dial. The effect you ‘feel’ is to make the fork more progressive, ideal for larger drops without sacrificing small bump performance.


Note: this following image does not relate to the above feature but relates to a question asked bellow.


Service guide: Marzocchi DH3 + XCR

 this service procedure is for the classic Marzocchi DH3, the routine can also be applied to the XCR (Nitro) and also the XC50/51 models (24mm stanchions)

Seal kit:
Y8501558/C

Tools
YR4208/C – low pressure shock pump
YR5008BZ - Air cap puller
seal press no longer available

General Tools
6mm allen wrench (extra long)
Cir-clip pliers
Flat bladed screwdriver

Service Instructions:
Let all the air out of the fork
Place air cap extractor tool on shreader valve (17)
Tap tool (thus tapping plug) 10mm into the stanchion (19)
Remove cir-clip from inside the stanchion (38H)
Pull upper plug unit out of the stanchion (17)

Empty fork of oil into a suitable container
Use an extra long 6mm allen key down the centre of the stanchion and undo (53)
Remove stanchion (19)
Remove Dust seal(20), cir-clip (38) & oil seal (22)
Clean fork components and check for wear & tear.
Replace oil seal, cir-clip & dust seals.
Replace stanchion & tighten foot screw
Re-fill with 20w oil (XC50/51 = 7.5w) 35mm from the top of the stanchion with the stanchion fully compressed.
Replace upper plug (17) & cir-clip (38H)
Pull plug (17) up hard against the cir clip (38H) using air plug tool to check that the cir clips is correctly seated.
Inflate to 30-45 psi


Workshop: Fixing 55/33 and DJ 'R' cartridge forks


The 2008/9 R system caused many problems for the 55, 33 and DJ fork, the cartridge was a bought-in sealed item that was gas charged. The problem with was that the sealing was relatively poor and the cartridge could suck in oil from the outer leg, this overfilled the damper and created hydraulic lock. The fork became very hard and suffered from a loss of travel.
The good news is that the fork can be fixed relatively inexpensively (if out of warranty). All replacement cartridges are converted to open bath, so when installed, fixes the fork 100% with vastly improved performance. The open bath cartridge differs via the flow holes at the top and bottom of the cartridge.

Part numbers:
Y703897 – fits 33 R/DJ 1/ 2 2008/9
Y703898>A – fits 2008 Z1 SPORT/55 R

Once installed put the following quantity oil (SAE 7.5W) into the leg:
DJ1 – 150 cc
DJ2 – 190 cc
55R – 160 cc

Put air on the other side so to find the best balance for the rider. Suggested range for model fork:
DJ1 – DJ2:  2÷5 BAR
55R : 2 ÷ 3.5 BAR
Push up/down the fork until when the fork works correctly.


Tuning tip: Oiling the foam ring.

For the 2010 season Marzocchi introduced a foam/ felt ring that sits between the oil and dust seal. When originally fitted these were dry, this can lead to a sticky – notchy feeling over small movements. Newer forks have the ring assembled wet, however it is good practice to look after them. *Update: 2013 forks do not have these fitted.

The simple solution is to just cut them out! However by wetting the ring with oil, small pump performance and sensitivity of the fork is greatly improved – in fact this mod was done to my own fork by Marzocchi’s race mechanic and the difference is incredible.

1/ Carefully prise the dust seal up using a small flat bladed screwdriver – be careful not to slip as not to damage the stanchion.


2/ inspect and clean the area underneath the dust seal.


3/ Using a syringe, soak SAE7.5w suspension fork oil (the same as what’s inside) in to the foam ring until it looks completely wet.


4/ Re-seat dust seal

5/ you will get some oily smears on the station the first time you use it, just wipe these off and they will disappear after a very short time.

UPDATE 2013

We have noticed that in the new production of 2013 models there in no foam ring. The tolerance can also be tight, so combined with the NOK dust seal it can create a 'sticky' feeling. Marzocchi recommend using calcium grease under the dust seal to keep things running sweet.

carefully lift the dust seal with a flat bladed screw driver

clean and inspect

We are currently testing Morgan Blue calcium grease

get it up and under the seal, work it in by rotating the seal.

Service guide: TST cartridge bleeding 2008<

This is the bleeding procedure for 2008 onwards TST units (without bladder) that can be opened via a nut at the base of the main body. If you cartridge doesn’t have the nut this guide is not for you & we will get to those later.
This procedure is easy, you just need to take the cartridge out of the fork to do it.

*A lot of 2008 forks had problems with cartridges locking out, this was due to oil in the leg being sucked inside the cartridge and causing hydraulic lock. To make sure this does not happen again, do not use any oil in the slider just use grease instead and the cartridge wont fail again. 

 

Service guide: Roco RC Coil Shock

Here is a great service guide video made by one of the Roco's designers. The Roco was designed to be user serviceable using normal workshop tools. The guide can be used for all of the Roco Cool family, the RC, WC, TST, R.

and the essential service info.

Description COMPENSATOR DEPTH Nitrous/Air pressure compensator chamber
     
AMM.MTB ROCO TST C.70 I.222'07 37mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.70 I.228'07 37mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.63 I.215'07 35,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.50 I.200'07 31,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.50 I.190'07 31,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.76 I.241'07 39,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.63 I.222'07  35,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO TST C.57 I.200'07 32,7mm (0/+0,1) 12/15 bar - 170/210 psi  
     
AMM.MTB ROCO RC WC C76-I241'07 39,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C70-I228'07 37mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C70-I222'07 37mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C63-I215'07 35,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C50-I200'07 31,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C50-I190'07 31,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C63-I222'07 35,7mm (0/+0,1) 12/15 bar - 170/210 psi  
AMM.MTB ROCO RC WC C57-I200'07 32,7mm (0/+0,1) 12/15 bar - 170/210 psi  
     
AMM.MTB ROCO COI.R C70 I222'07 75mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C70 I228'07 81,6mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C63 I215'07 78,1mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C76 I241'07 88,1mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C57 I200'07 69,8mm (0/-0,1)  12 bar - 170 psi  
AMM.MTB ROCO COI.R C50 I200'07 79,2mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C50 I190'07 69,7mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C38 I165'07 59,1mm (0/-0,1) 12 bar - 170 psi  
AMM.MTB ROCO COI.R C63 I222'07 78,1mm (0/-0,1) 12 bar - 170 psi  

Service guide: Z1 Bomber 1997

Found this service manual, these were actually included in the original owners manual. This is nice as the service for the cartridge type fork hasn't really changed over the years and can be considered a definitive guide for all Z1 models 1997-2002.






















Travel Adjust - Marzocchi forks 2010 +

In 2010 Marzocchi completely dropped the ATA travel adjust and reverted to a travel limiting spacer.
Models covered are 44 Micro Ti, 44 TST2, 44RLO, 44LR, Corsa LR, Marathon LR, Marathon R, 55CR, 55R.

The travel spacer is available as a spare part, Y536181, ssp £6.95 each

For new 2012/13 LR, CR and R models and additional bleed of the Dynamic bleed cartridge may be necessary, for this you need to watch this video:





 

Service guide: Marathon S 2002

Here is a great pictorial guide to service the Marzocchi Marathon S fork. This guide can be used for later models, however for the 2003 model year Marzocchi changed the bush design to the 2 peice design.







ETA Remote Control Instalation

For 2007 Marzocchi offer a remote control device for the ETA on the XC600 model, this was a lot simpler than the TST version as this had an internal return spring.

1/ Remove the outer cable ferrule and using gear cable cutters shorten the outer cable by 55mm.
2/ Reinstall outer cable ferule and fit the cable to the cable guide.
3/ Using a 2.5mm hex key remove the centre fixing screw and using a 2mm hex key loosen both grub screws.
4/ Remove ETA cable rotor mechanism, making sure you note its resting position.
5/ Tighten the 2mm grub screws to lock the cable in the cable rotor.
6/ Rotate the cable rotor making sure to wrap the cable in the rotor’s cable groove.
7/ Install the rotor in the resting position.
8/ Using a 2.5mm hex key reinstall centre fixing screw.
9/ Check the function of the lever and adjust any cable play using the lock nut adjuster


 

TST Remote Control instalation

The original remote control for the TST5 cartridge could be an immense faff, especially if you followed the Marzocchi handbook and used there little tool. This guide was developed by Marzocchi's Euro tech support.
The models that used this were the 2007/8 Marathon and Corsa LT models




Travel reduction: Z4/ MXC series

Another guide for UK mag MBR, this time we looked at the travel reduction of a simple damping rod model the MXC Air. This time we used an inverted technique where we could retain the volume of oil inside the stanchion.

Service: 1998 Z5 and Z4 series

This is an old service guide we did for UK magazine MBR. Although the forks are old the procedure hasn't really changed.