Marzocchi 48mm CC Forks

Yes. a higher PFP pressure will add to the force that will try to extend the forks. I have not done so, but it could be easily tested when assembling the cartridge. When compressing it by hand, it extends at a certain speed. If you wind the PFP in, not changing anything else, I would expect it to extend faster. Under these circumstances, no cavitation should be present.
But in the real world when riding, if GMP's thesis is correct, a certain amount of cavitation will be present, and that amount can be controlled by the cartridge pressure via the PFP.

Trying to understand suspension behaviour is an interesting topic, I must say! Does that make me a geek? In any case, I can live with that :)

BTW, I tested my new setup today. It has been raining a lot lately, so the track was difficult to ride with a lot of new baseball to soccer ball sized rocks emerging. I couldn’t really compare to last Wednesday's ride (when it was hot and dry) but I think my rebound has got a bit slower. I rode at 10 and later 8 clicks today, and that could be compared to around zero clicks with the old settings I think.

I also tried to soften the compression a bit by removing a face shim, but I am uncertain whether it really made any difference. Perhaps I need to soften the midvalve slightly?
However, I got a comment from a friend that watched us riding up a rocky hill: "I saw that your forks worked very well and followed the terrain better than the others (that are on orange machines most of them). I guess that is a compliment to the Marzocchis, and that I am getting close.
 
Remember the mid valve sees a lot more oil flowing through it than the base valve does, and as such any changes at the mid are much more pronounced.
 
Anders said:
That's good news. Would you share how your compression stack was altered? And what oil you are using?

I'm rebuilding my own stacks at the moment. This my second attempt.



Sent fra min GT-I9295 via Tapatalk
Click to expand...
Hi Anders
It has been a long battle sorting my forks out so hope this a help to you..a local tuner had been in mine and basically Put valves in upside down and shims in different order in each leg.
I'm lucky enough to have a good mate who owns a bike garage who has been great help in sorting this out and getting hold of the information needed

I took out 1 x 32 x 0.15 and 2 x 11 x 20 in the cartridge compression stack.
cartridge air gap as manual (had some knocking first time so dipped valve in oil to remove air)
300cc in outer chamber
pfp at 1.5
rebound 16
compression 15
new bushes and fork seals and internally new seals on damping rods as one was leaking all the oil out of the cartridge.
my cartridge spring is 3.9mm (2012 racing) we have measured the spring in a 2017 is 3.5mm.. I'm guessing this has been altered to soften things up ?
have put in silkolene rsf 7.5 ..
http://www.silkolene.com/motorcycle/suspension-fluids/rsf-7-5/
Herdy
 
Last edited:
So I have read through this entire thread to the best of my ability. In my defense I'm under the weather....regardless, what bushings are you guys using? Is the consensus to use the Yamaha KYB units? Or was the fitment wonky? What is the part number/manuf for the bushings you guys are using?
 
Awesome thread! I serviced my forks over the weekend and before starting the job I was quite afraid to be honest (after reading all the stories about bleeding, having to use straps etc). I printed out the posts made by GMP and Simmo737 and it was VERY HELPFUL. I poured in 210cc of KYB fork oil (was told by our Estonian dealer that it's the best to use) and let it settle for 20-30 mins, corrected the oil height to 140mm, raised the rod and inserted compression (shook it around a bit when comp stack was in oil to get air out) unit while lowering the rod. I didn't have to push hard to get threads started so this was the first win. I tried to push the damping rod up as quickly as I could with hands, but didn't hear any air escaping, so I took it out of vice and pushed on table about 10 times. There was only a small rain drop amount of oil coming from the bleed holes. Slowly cycled the damping rod, didn't hear any bubbles, turned it upside down and *slurp-slurp*... oh well, some air is still in that I wasn't able to get out. So with the second fork I decided to try and use oil level of 130mm from top. Didn't still have any difficulties inserting the comp unit, but now I got a fart out of it when cycling only by had. One more burp when compressing on the table and a few drops of oil came from the bleed holes. When turned upside down, I still hear some air in there but definitely a lot less than the other fork had. So I opened the other one and also topped it to 130mm. Seems to be good enough :)

However, the bushings on the comp unit are bad, they have some worn out places. My dealer told me that it's impossible to get new ones so now I'm looking if someone can coat them for $$$.
 
I don't know your location, but I would try other sources.
LT Racing in the Seattle, Washington area.
http://ltracing.com/

Works Enduro Rider in New Jersey.
http://werproducts.net/

In my 18 year association with these two suspension tuners, they've always had or come up with the parts I need.

Good Riding and Wrenching to You!
Jim



.
 
So, did anyone ever come up with a definitive application crossover for the forks springs?

I have two tuners locally tell me that they need to pull them so they can match up a spring. I plan on doing all the service myself so I would like to have springs ready to go when I pull them apart.
 
SS109 said:
So, did anyone ever come up with a definitive application crossover for the forks springs?

I have two tuners locally tell me that they need to pull them so they can match up a spring. I plan on doing all the service myself so I would like to have springs ready to go when I pull them apart.
Click to expand...

Main spring or PFP spring?
 
Should be FRSP 4447, only thing this is 5mm shorter than original. You just need to adjust the fork spring preload clip one notch further.
 
For the record:
I found the pfp springs on my 15 200 to be 1.4 kg/mm. I measured one using my bathroom scale, and used the milling machine to compress it 20mm. Then the scale showed 28.3 kg.

I will try to replace them with Racetech springs of 1kg/mm, just to see the difference.
 
hi anders are your ppf springs the original marzocchi ones . no one had anything in the uk softer than 1.6 .looking to get some 1s myself .anyone no what rate my 013 ppf springs are
 
rvktm said:
hi anders are your ppf springs the original marzocchi ones . no one had anything in the uk softer than 1.6 .looking to get some 1s myself .anyone no what rate my 013 ppf springs are
Click to expand...

I'm the only one that have worked on my forks. So I know for sure that these are the OEM pfp springs.

I bought mine 1.0 springs on ebay from the US.
http://r.ebay.com/pZYjgj
 
Curious how the lighter pfp springs will affect fork performance. What are you trying to achieve with them?
 
You must log in or register to reply here.

Similar threads

S
Newbie GasGas owner / help with suspension tuning
2
Replies
23
Views
10K
Jakobi
Jakobi
N
Diving into the Sachs 48mm forks - wish me luck?
3 4 5
Replies
83
Views
43K
Ryan218
R
Back
Top