2011 45mm Marzocchi Manual or defaults?

T

Thompo

Member
2011 45mm Marzocchi Manual or defaults? Shims in 2nd post

Hi folks, New here.

Picked up a UK 2011 250 cross country with 45mm Marzocchi forks (black tubes, black stanctions, no external preload adjuster) and Ohlins rear.

I searched the site and found a manual for Shivers but mine aren't quite the same inside as the manual suggests.

Is there a list of default shims for the various stacks?
Default spring rate etc?

Thanks for any info
 
Last edited:
Hi,

I bet GasGas UK special ordered that spec to avoid the hideous first Sachs 48 forks.

I would guess you would get close by looking at 2007-2008 EC250/300 documentation.

Mz Shiver 45's are your type with open-cartridge, Shiver 48's are the twin-chamber type.

Target weight for stock springs I think in about 70-80 kilos, which is too little for me. I'm 90kgs. Getting a 5.4 shock spring for wasn't a problem, but 4.5Nm fork springs was not easy. I finally found a suspension tuner here in Sweden that had a chat with Ohlins and he got me a set, but they were too short. I had to make a nylon spacer, to add to the stock black spacer under the spring, to remove any free play. Stock space in my fork is approx. 6cm and the homemade one is about 4cm. I'd rather have a longer spring, but that's secondary.

Shim stack is typical GG with lots of free-bleed.

Good luck.
 
Apologies i forgot about this thread!

Thanks for the info had my first proper test ride over the weekend and it was terrible. Forks transmit EVERYTHING through the bars, 20mins riding mainly rough tracks and rocky patches 2nd-3rd gear mostly my hands and arms were done. Was a bit of a handful over brick size rocks just skipping and jumping about. Tried moving bars, levers adjusting clickers no good.

Swapped bikes with my mate, WR400 his felt so composed and comfy, would glide over bits i was being thrown around on, could ride all day on it but had to stop as my mates hands hurt after 5 mins on the gasgas

Pulled the forks apart tonight to set about trying to make them work.
Any advice? Im 105kg looking for an enduro setup no MX, clubman sort of standard with a trials background.

7.5wt Silkolene, new seals and bushes. 110mm air gap

Paint is off rear spring and i havent got the fronts out yet to measure.
front sag is 80mm, rear 105mm so im guessing springs are about right unless damping is masking something.

this is the valving i found on the base.
23x1
23x1
23x1
23x1
23x1
23x1
23x1
23x1
23x1
23x1

11x2

22x1
22x1
22x1
22x1
21x1
20x1
19x1
18x1
17x1
16x1
15x1
14x1
13x1
12x2
12x2

Seems like a load of shims compared to anything i have found admittedly these all appear to be 0.1mm thick which i havent seen either.

Havent got the tools to get into the rebound valve yet but the clicker doesnt have much effect so i guess it needs some work too.

Thanks for any info
Neil
 
Turn the base valve upside down and try the same stack again. I've not tried this yet but if you read my thread I've already gone too far to try it. The restriction to the rebound should help as should the additional area to the compression.
 
Good thinking!
Had been looking at modifying the existing piston or making something along the lines of a gold valve after reading the ports are very restrictive.

Found a problem stripped the other leg....
base valve came apart as i buzzed it out, dunno if buzzing it out caused the screw holding the stack to come out or not but i had to go fishing to find the screw spring and check plate.

Additionally the stack is missing a load of shims on the HS.
Stack is
23x1 x10
11x2
22x1 x4
21x1
12x1

its missing 20,19,18,17,16,15,14,13,12 shims and they arent inside the fork:mad:
 
I am going to give the existing base valves a try using some shim stacks I found on the Cafe Husky forums posted by some of the more experienced guys.

I posted them in motopsycho's thread. They are pretty standard and are similar to other nice working forks I have seen.

Terry Hay has posted that these base valves are capable of providing good results and are not really too restrictive. He says the shim stacks are actually more restrictive than the ports. I can believe that because it looks that way to me too. I have not actually done the calculations, but Terry is one of the best tuners on the planet, so I trust his judgment.

Lots of other things can make the fork harsh besides base valve port size. For example I hear that rebound needs to be increased on these forks to reduce harshness feeling in your hands when the forks rebound too quickly.

Will see how this works out.
 
I'd still say try turning them over. After putting my new valves in with the same stack and smaller bleed hole, you can still feel a dramatic decrease in resistance on the high speed compression. Also it might be worth noting that the difference between 5w and 7.5w (iso 22 and 32 hydraulic oil in my books!) Might be the difference between plush and harsh with the correct shim stack and maybe mid valve...

Food for thought anyway! The local tuner ground the compression side inlets open a little on mine and stated vehemently that I should run 5w oil only. But with the shim stack and free bleed he provided on 0.5 springs with his 2mm recommended preload, half the stroke was lost on the smallest bumps, let alone the rough stuff.
 
Built it up last night and just bouncing around the garage I don't feel much difference, will have to wait until weekend to get it out again.

One thing I did notice, if I sit on the bike, it settles into its travel front and rear, if I bounce on the seat or pegs, only the rear moves forks don't budge unless I put the front brake on and push them down.

Either my rear is waaay too soft on the valving (105mm race sag, spring seems ok?) or the forks are binding (clamps only snugged up to check).

Tonights goal will be to remove the springs (just had the base valves out) and check they aren't binding when mounted to the bike.

Read a few things that point to bushing lands being too tight that can cause binding. A 1? taper is machined leaving 8mm support band to provide some wriggle room for the bushes, Im guessing it is the fork stanction that gets fettled as it carries the bush that moves through the clamps?
 
I don't have experience with the 2011 forks myself, but seem to remember some comments from the time;
Something about the upper fork tubes being thin and easy to deform if the lower triple clamps are tightened too much. If you experience some binding, perhaps you should try loosening the lower triple clamp bolts a little.
 
It is nice if the forks and shock move the same amount when you bounce, but the folks will generally have more friction so sometimes don't move as well unless the seals are greased and the bushings are in good shape and the oil is fresh. Mobile 1 AFT seems to produce less seal friction and is a good choice for these forks.

Make sure that your bushings are not worn when you take the forks apart and replace them and the oil seals when you can.

Your forks have 10 face shims on the base valve. That is way too many. Most people only use 3 or 4 for off road.

The reason your rebound control is ineffective is that:
1. the rebound shim stack usually doesn't have enough shims (add shims as identified below)
2. there is a bleed hole drilled in the rebound piston (leave it alone for now)
3. usually there is a bleed shim on the face of the rebound stack (remove it)

The base valve piston also has a bleed hole. You can leave it alone for now.

I suggest you try something like these stacks (credit to Motosportz, Kyle Tarry & GMP at CafeHusky):

If you don't have these exact shim sizes, just use what you have to get close. It is bound to be better than what you have.

Base Valve:
22.1 (3x)
14.1
20.1
18.1
16.1
14.1
12.1
10.1

Midvalve assembly (rebound stack on top with midvalve stack below piston):
<nut>
15.1
17.1
18.1
19.1 (2x)
22.1 (2x)
<piston>
22.1 (2x)
20.1
18.1
16.1
14.1
12.1
10.1
18.1

Float is about 1mm with this midvalve setup

I implemented these stacks on my forks this week and am going to try 130 mm air gap using Mobile 1 ATF (7.5 wt). I'll ride it this weekend.

If your midvalve nut has never been removed it will be difficult to remove the first time since the midvalve shaft threads have been peened to prevent the nut from backing off. Mine had already been taken apart, so I am not familiar with how to get the nut off in the first place.

Look up that procedure and be careful and take it slow. You don't want to twist off the end of this rod since that will disable both the midvalve compression and the rebound functions.
 
One more thing. Your Silkoline 7.5 wt fork oil should be just fine, so don't go out of your way to get something else if you already have some left over.

I just suggested Mobil 1 ATF since it works well and is easy to get at local auto parts stores. Guys on the KTM Talk site used to use gallons of it on their OC WP forks back in the day.
 
hi Folks,

Finally got around the riding the bike again after removing 2 shims from LS in each side and dropped the oil level to 120mm.
Felt similar and hands still sore after a short period of time.

Fully stripped them this weekend and checked a few things.
Forks were rebuilt 6hrs ago with fresh oil bushings and seals.
Everything looked good inside except the oil which was very metallic.


Made quite a few changes hopefully to give me a workable base line.
Compression should now be noticeably different (for info piston has no bleed).
WAS,23,23,23,23,23,23,23,23,23,23, 11 ,22,22,22,22,21,20,18,17,16,15,14,13,12,12

IS, 23,23,22,18,15,14, 11 ,23,22,21,20,19,17,16,13,12,12

Found the standard rebound stack to be
Check valve,Piston,22,12,19,17,15,12. Rebound piston has a tiny bleed hole ~1mm.
New stack to try and get the adjuster working
Check valve,Piston,22,22,12,22,19,17,15,12

Im aiming for compliance over rocks and roots typical of Irish forest enduros. Would it be best to stick with the check valve or a mid valve arrangement? Max speed in rough ground likely to be middle revs in 3rd. Im not fast lol

Is the "Float" the amount the check valve on rebound side can open? I think we checked it around 1.5mm.

We suspect the metallic oil could be the damper rod deffo does not appear to be coated. Cleaned it well and gave it a light rub with polish and rag was black, seems like raw Alu, would be very easy to mirror polish as most of it already is!

Also found what I assume is a type of bottom out valve assy, not adjustable but must be removed to get the damper rod out.
Pic attached.

Cheers
 

Attachments

  • 20171118_135203.jpg
    20171118_135203.jpg
    113.5 KB · Views: 27
Just thought I would update this.

I stripped and cleaned the forks again and rebuilt them broadly inline with the info above (Thanks ssaulnier!) creating a midvalve setup with what I had available, added 6mm preload and rebuilt using some AW32 hydraulic fluid.

Forks are significantly improved, granted I was only out around a forest and never into 3rd gear but my wrists were not sore after 2hrs, where previously 10mins was enough to cripple me!

Mate has just got a 2006 200. His forks seem very plush compared to mine so ill have a look inside when doing the seals for him.
 
You must log in or register to reply here.
Back
Top