Anyone had experience with the late Marzocchi fork (2004)?

[dale-j]

Hi all.  Had a bit of an interesting experience flying blind last weekend trying (well, succeeding eventually) to change the fork oil in my late Marzocchi forks.  I have a 2004 v11 LeMans and at 23,000 km it was due for a fork oil change.  I also intended to lighten up the fork oil as Steve Gurry recommended (and did to good effect) on my brother in law's 2001 V11 Sport, to reduce the harshness of compression impacts and fix the spooky handling issues I've been chasing at bigger lean angles on my bike.

 

These had to be the oddest set of forks I've ever worked on.  The top caps would not come off when loosened, but were affixed firmly to the top of the cartridges, which in the usual manner were and are bolted in to the lowers.  Removing the fork caps to change the fork oil required disassembling the front wheel and fender and removing the cartridge bolts, which double as oil drains.  The whole of the cartridge and the fork cap then comes out as a unit.

 

No simple process of popping the fork cap off to suck out most of the oil and then remove the springs to reset the oil level with compressed fork.....  it's not even possible to take the springs out while leaving the cartridges in to check oil level!  I ended up thoroughly draining (and cleaning) the cartridges and lowers and then going with a volume measurement.  That would be a first for me, filling without measuring the actual level.  Odd, but there appears to be no way to take a conventional measurement.

 

In any event, my question (yes I have one and I'll get to it) is that I need to add a bit more preload to the fork springs, and I can't figure out how I would disassemble them to do it.  The spring rate appears fine, I just have too much of both static and rider sag and need to add to the captured plastic spacers (new longer ones actually) that are captive with the springs between the cartridges and the fork caps.    The manual I have (2003) is of no assistance as it does not show enough detail, and the detailed manual I have is earlier and consistent with my brother in law's Early marzocchi's with the compression in one leg and rebound in the other.  I have rebound damping adjustments on both legs, no compression adjustability (just an unused adjuster boss on the fork lower to frustrate me) and from conversation to date with the local suspension guru apparently the swaged fork cartridges that can't be disassembled.  There must, however, be a way to change springs and preload spacers.

 

By the way, I have changed to a lighter (7w blend) Amsoil synthetic fork oils from the original fill in the forks, which incidentally appeared much, MUCH heavier than the 10w that the manual calls for.  The change has been fantastic and with a bit more preload I hope I'll have her dialed in.

 

I did see a reference to sticking a small allen key in to a set hole on the cartridge, walking the spring down and undoing a nut under the fork cap.  Tried this, and the nut just seemed to spin (or perhaps the preload nut on top I was holding did) and all I got from it in the end was a buggered allen key.  There must be a more robust and reliable way to do this.

 

I realize that the later V11 bikes are a pretty small subset of the population and most I've seen posted about have been the later Ohlins forks.  I'm not that fortunate, but would be happy with the performance of mine (with the new fluid) if I could just figure out how to get the preload correct.   Anyone help?

[helicopterjim R.I.P.]

If you live in the Fraser Valley and you don't mind spendin a few bucks then try RMR Suspensions in Abbotsford. He can do wonders with the forks .... Traxxion Dynamics kit even.

http://www.rmrsuspensions.com/

 

Otherwise you need to search the site for some of the upgrades done to the Marzocchi's.

[Tom M]

The top caps screw onto the top of the piston rods (?) and are secured by jam nuts on my '02.  The later 'zokes like yours are similar.  Once you unscrew the top caps and collapse the forks you can hold the top nuts, loosen the jam nuts, then take them both off to remove the springs and preload spacers.  You can set your oil height that way too.

 

Here's a thread with pics of your fork internals by a former member here:

http://www.v11lemans.com/forums/index.php?showtopic=12946&do=findComment&comment=144447

[Baldini]

Don't know much about it but they have preload adjuster do they? If you can't set sag with that, sounds to me like you need stiffer springs.

 

KB

[dale-j]

If you live in the Fraser Valley and you don't mind spendin a few bucks then try RMR Suspensions in Abbotsford. He can do wonders with the forks .... Traxxion Dynamics kit even.

http://www.rmrsuspensions.com/

 

Otherwise you need to search the site for some of the upgrades done to the Marzocchi's.

Yes, even before my first go at the forks this was my intent.  I have called, emailed, left messages etc.  Got one voicemail back from Rod stating they couldn't work with my swaged cartridges and nothing since.  Thinking they are not particularly interested in the headache.  Good suggestion, though.  Thanks.

[dale-j]

The top caps screw onto the top of the piston rods (?) and are secured by jam nuts on my '02.  The later 'zokes like yours are similar.  Once you unscrew the top caps and collapse the forks you can hold the top nuts, loosen the jam nuts, then take them both off to remove the springs and preload spacers.  You can set your oil height that way too.

 

Here's a thread with pics of your fork internals by a former member here:

http://www.v11lemans.com/forums/index.php?showtopic=12946&do=findComment&comment=144447

Thanks, Tom.  I'll have to look at it at home where the pics aren't blocked, but that probably shows what I need to figure out those jam nuts.   Makes MUCH more sense at that point, as then with the cartridges in I can also as you note check proper oil height.  Will post back when I can see it later on, but it looks like this will be what I need to get it nailed.   Thanks again...

[dale-j]

Don't know much about it but they have preload adjuster do they? If you can't set sag with that, sounds to me like you need stiffer springs.

 

KB

Hey KB.  I initially thought the same but it appears that here this is not the case when I got in to the actual measurements.  To summarize my limited knowledge of sag, you want a 'static' sag without rider of 10-15mm to allow some top out resistance, and a sag with rider (varies by taste) of 25-30mm.   If you need to add so much preload for the rider weight that at the recommended rider sag there is not sufficient 'static' sag then as you say the springs are too soft.  In this case, the problem is insufficient factory preload for the weight of the bike in the front fork.  Mine sitting without rider sags 40mm (!) at full preload on the cap adjusters, and adding my 175 lb weight it goes only to 50mm.

 

As an aside -  now rechecking my numbers I can see why the kickstand drags in lefts .... oops.

 

If preload was totally linear, this would look like the springs were borderline too stiff for me.  Seeing as it's not totally linear, adding about an inch and a quarter (32 mm)... or maybe even and inch and a half of preload should allow the bike to rest at a static height of approximately 10mm, right in the zone for static sag and with more available by releasing some of the cap adjustment that's maxed now if I overshoot it a bit.  Assuming no adjustment this will provide a rider sag of approximately 18mm - maybe a hair too stiff.  Backing off the caps to provide 15mm static sag would have me bang on where I want to be, as it isn't actually a 1 to 1 between preload and ride height, it takes a bit more spring compression than 1:1

 

I'm sticking with the springs as stiffer would further exacerbate the issues I'm having with high speed compression harshness, but what I do need clearly here is a  bit more preload - not more spring.  Together with the lighter fork oil improvement on the compression issue already (thankfully lots of rebound adjustment to compensate for the thinner oil) I think this will exorcise my handling demons.

[docc]

Adding that much preload will use up your rebound travel as in when you are leaned well over and the front needs to "reach out" to keep contact with a low spot or off-camber section. If there isn't enough "reach" or "rebound travel", the front will wash out.

 

I tried the increased preload spacing and the wash-out wasn't pretty. With your observations and measurements, I'll stay in the "correct springs" camp.

 

Getting your springs spec'd won't make the compression damping harsher. Paradoxically, a softer spring causes suspension travel to "hit" the dampers harder, especially the built-in high speed circuit.

 

You're on the right track, man! Your gorgeous LeMans is just gonna get better and better!

[helicopterjim R.I.P.]

 

If you live in the Fraser Valley and you don't mind spendin a few bucks then try RMR Suspensions in Abbotsford. He can do wonders with the forks .... Traxxion Dynamics kit even.

http://www.rmrsuspensions.com/

 

Otherwise you need to search the site for some of the upgrades done to the Marzocchi's.

Yes, even before my first go at the forks this was my intent.  I have called, emailed, left messages etc.  Got one voicemail back from Rod stating they couldn't work with my swaged cartridges and nothing since.  Thinking they are not particularly interested in the headache.  Good suggestion, though.  Thanks.

 

 

Sorry to hear that .... he was quite interested in doing mine a few years ago but I do know that his business is doing very well but he finds it hard to get employees that can really do the work.

 

Like you say ... he may not be interested in strange stuff but if it was Ohlins ...... he's probably be all over it. He definitely did not like my Elka shock on my Ducati 749 .....

 

 

Hope to see you out there if I ever get home long enough to go for a ride .....!!

[PDoz]

Is it feasible to make a c shaped spacer ?

BTW, let me know how you go....it's on my to do list.

[Skeeve]

 

 

I'm sticking with the springs as stiffer would further exacerbate the issues I'm having with high speed compression harshness, but what I do need clearly here is a  bit more preload - not more spring. 

 

 

 

The stock fork springs max out at about a 150 lb. [70kg] rider, iirc. If you weigh more than that in full kit, or expect to carry a passenger ever, you need to replace the stock fork springs. The stock fork springs are the weediest looking things you've ever seen; if you straightened them out, they wouldn't be even as long as the forks [unlike most fork springs, which seem to have enough coils to be longer than a bike with trailer when straightened out.] New fork springs are going to be less than $100 last I checked, and you can get almost exactly where you need to be w/o having to fiddle w/ extra preload spacers [which are just a kludge for not having the correct springing anyway...]

 

Best o' luck

[GuzziMoto]

As mentioned in the other thread, if you only have 10mm of sag from the bike only to you on the bike then something is wrong. Either the measurements are off, or the springs are too stiff. The fact that that 10mm of sag happens between 40mm and 50mm with preload cranked all the way up also says something is wrong. Perhaps the springs have been replaced, maybe the replacement springs are even shorter. Or maybe the previous owner cut the springs to stiffen them but did not replace the cut out length of spring with a spacer.

It could be a lot of things, but 40mm free sag and 50mm race sag is typical of springs that are too stiff and too short.

[docc]

What GuzziMoto said ^

 

The previous owner must have screwed the pooch on this one. Time to start over with correct springs for your weight (with gear). When Traxxion Dynamics delivered mine, the preload spacers were perfect.

[GuzziMoto]

And to take it further, if your measurements are correct and the springs are too stiff and too short then that could be the source of your suspension issues. Too stiff, well that is self explanatory, and too short would cause the suspension to ride down in the stroke where there is less compliance and less travel.

Fork springs are cheap in the scheme of things. A proper set of straight weight springs of the rate required for your weight and riding style won't set you back much $$$. And they could save you a boat load of hassle trying to fix issues that the wrong springs are causing.