Fork Oil Change

[Guest MikeC]

Mike, if you're changing out the springs, you'll need to remove the nuts that secure them at the top.  These nuts can be set anywhere in a range, and I haven't been able to determine if or exactly how this affects preload (or what the range of adjustability is, if any), so I put 'em back where Mandello set 'em and adjust preload entirely with spacers.  The stock setting of the nuts is 22 mm from the top of the nuts to the top of the threaded part.  You'll see.  RE: fork cap adjusters (compression and rebound), I was WRONG when I said clockwise, I meant COUNTER-clockwise (see edit above), sorry.   Yep, the service manual makes a point to have you set them to the lowest notch (without forcing anything) before you take the caps off.  Why is this important?  It's yet another Mandello mystery to me, (could this let the oil drain out easier?) but that's what it says.

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ratchet...Got cha. I'm going to make some calls today regarding heavier springs. I'll give traxxion a call, see what they have available. Spectro oils are hard to come by in NJ as Bel-Ray has a local distributor so most everyone carries that brand. Their website says their "fork oil" is good for cartridge forks. Some places carry Red Line products I'll see if I can get their fluids locally. Late in the season here so most shops are gearing up for the winter motor sports (snow mobiles).

 

Thanks to everyone who replied. I love this place.

 

Mike

[Guest MikeC]

Ratchet...29.5cm free length. That converts to 11.6 inches. Is that correct, our springs are that short? I'm not accustomed to cartridge forks so this is new to me.

 

I just want to make sure if I order springs I give the guy the correct info.

 

Mike

[Guest ratchethack]

No prob, Mike. I see your Momma didn't raise no dummies either. Trust but verify - words to live by. And Part II - be suspicious - be very suspicious - of anything and everything you read on the Web.

 

Since I still have my stock springs handy on my workbench, sitting in the box the new Wilbers came in, it was easy to measure 'em again (I measured both this time, and FWIW, they're within ~ +/- 1 mm of each other at 29.5 cm.

 

Spectro used to have a handy comparo chart on their site that graphed out viscosities of competitive cartridge fork fluids against competitive fork oils. I had linked to this chart in a post awhile back, but they've evidently moved or deleted it, 'cause it ain't there now.

 

Have fun, and assuming you get a decent match of spring rate to load - IMHO, feel free to set expectations HIGH!

[BrianG]

Steve is not the first Canadian to suggest that their bike was adequately sprung....could it be that the Canadian bound models came with heavier springs??????

 

EDIT Brian, did you measure sag with the OE springs?

 

I also theorize that you should have just a little more preload on the rebound side.

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Mine is a US bike that I imported, so I can't comment on that part.

 

Loaded Sag with the original springs was almost 50% and the rear is 40+%, but worse than that, my compression damper was totally shot. It about tossed me over the bars on hard braking!!

 

I sent the forks to Max and got his new cartridges installed, so now I have fixed compression damping and adjustable rebound damping on both sides. Plus the 1.05kg springs.

 

I have a Penske shock/spring awaiting installation for the other end!

 

Also, I don't recall having to remove the damper rod top-nuts. I recall just removing the spring-keeper collets and pulling the spacers and springs past the nuts........ or am I nuts?? (gotta quit smoking that stuff!!)

[Guest ratchethack]

Brian, I agree 100% with your observations. You've been out there ahead of me for quite awhile on a lot of this Marz fork stuff. Matter of fact, I would've been better off to have paid closer attention to your posts a couple of years ago (I think?). In any case, I sure would've been far better off to have upgraded fork springs way back when. You're correct about removing the spring keeper collets. If you can get new springs in without taking off the nuts, this would be simpler and easier. But in my case, I could get the old ones out this way, but the new springs required substantial additional force to get preload on 'em (considerably more force than the stock springs) just to get them installed with the stock length spacers (which I now need to shorten up by 5mm, by my sag calculations). In my case it would have been pretty difficult to get the new ones in without a specialized tool to compress the spring, along with another specialized tool to hold the damper rod in it's fully extended position. By backing off the nuts, I found that I could do the entire change-out by hand, without the need to fab up some special implements. I'm guessing it would have been even harder with straight-rate 1.05-1.1 kg/mm springs. I reckon you must've at least used some home-shop fabbed gizmo of some sort, along with another pair of hands? My new springs, (GuzziTech Todd Eagan's recommended Wilbers progressives), are considerably stiffer than stock, but not quite as stiff as yours. Of course and as always, YMMV.

[BrianG]

Brian, I agree 100% with your observations.  You've been out there ahead of me for quite awhile on a lot of this Marz fork stuff.  Matter of fact, I would've been better off to have paid closer attention to your posts a couple of years ago (I think?).   In any case, I sure would've been far better off to have upgraded fork springs way back when.   You're correct about removing the spring keeper collets.  If you can get new springs in without taking off the nuts, this would be simpler and easier.  But in my case, I could get the old ones out this way, but the new springs required substantial additional force to get preload on 'em (considerably more force than the stock springs) just to get them installed with the stock length spacers (which I now need to shorten up by 5mm, by my sag calculations).  In my case it would have been pretty difficult to get the new ones in without a specialized tool to compress the spring, along with another specialized tool to hold the damper rod in it's fully extended position.  By backing off the nuts, I found that I could do the entire change-out by hand, without the need to fab up some special implements.  I'm guessing it would have been even harder with straight-rate 1.05-1.1 kg/mm springs.  I reckon you must've at least used some home-shop fabbed gizmo of some sort, along with another pair of hands?  My new springs, (GuzziTech Todd Eagan's recommended Wilbers progressives), are considerably stiffer than stock, but not quite as stiff as yours.  Of course and as always, YMMV.

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I'm lucky in this regard.

1. I had Max McAllister as a mentor, way back in my VFR days.

2. I have a wife who grew up on a western Canadian farm. (she's no stranger to a greasy shop)

 

I fab'ed a simple spring compressor/collet tool from a 1' long piece of PVC pipe. Just cut a notch in it about 160 degrees around the circumference at the bottom, and stick a bar through a hole across the top end.

Hold the fork bottom in a soft-jaw vice.

Wire the top of the rod to a bungee - to the ceiling.

I compress the spring by pulling down on the bar so the spring is just below the "nut".

She slips the collet under the edge of the nut

I remove the pipe and use a pair of pliers to set the collet all the way in.

 

No fingers lost....

No days in the dog house for wounding the wife!

[Guest ratchethack]

Ah, that explains things. You were apprenticed at the knee of a bit of an industry suspension icon. Then there's the "can do" farmer's mentality and attitude of the wife. Didn't I read somewhere that just about every top racing team since the dawn of time has had a farmer in the most critical role? He's the "go to" guy in do-or-die situations (aka "magician") when you absolutely have to get stuff done yesterday, fix wot's broke, and keep stuff running long after everyone else has given up in frustration...

[Steve G.]

Errrrrrr........IMHO, per my experience and per the literally dozens of similar opinions on this forum from those who have also done it (and who are also more [ahem] gravitationally endowed) - anyone of 200 lb or above who doesn't go considerably stiffer on fork springs is substantially missing the fabulous handling capability engineered into these machines.  Of course, as always, YMMV.

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Errrrrr.........IMHO, it's your money!

Of course, as always, YMMV.

Ciao, Steve G.

[dlaing]

Loaded Sag with the original springs was almost 50% and the rear is 40+%, but worse than that, my compression damper was totally shot.  It about tossed me over the bars on hard braking!!

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No doubt, you benefited from the stiffer spring

For some reason I doubt SteveG has the huge sag that we had.

[Guest ratchethack]

Errrrrr.........IMHO, it's your money!

Of course, as always, YMMV.

                                                                          Ciao, Steve G.

Steve, if I have offended, I apologize, I truly meant no offense whatsoever. As Dave suggested, it seems that you may have different fork springs than standard issue. If I may ask, what are your loaded and unloaded sag measurements (in mm or %) on the front end? Enquiring minds just gotta know

[Gio]

I have a Canadian spec V11S (2000) and weigh ~180 plus gear. I would say the stock fork springs work ok with 10w oil after adding longer spacers (109 stock + 11 = 120mm). This decreased front sag from 38 to 23mm

 

Gio

[Guest ratchethack]

Gio, I had the same sag with stock springs and spacers. What's your unladen sag with the 120 mm spacer?

[Gio]

Hi Ratchet,

 

With stock spacer I measured 124mm topped out, 100mm unladen (= 24mm) and 86mm laden (=38mm)

 

With 120mm spacer I measured 125mm, 115mm (=10mm) and 102 (=23mm) respectively.

 

Gio

[neville briggs]

When I first bought my 2000 V11 it was handleing like a pig on a pogo stick.

I drained about 150ml of piss out of each fork leg and refilled with 400ml of 10wt fork oil and it transformed the front end.

Then it was just a question of tuning the suspension properly and hey presto a great handling bike. By the way I weigh around 110kg with all the riding gear on and the static sag is ok.

 

Neville Briggs

[Guest ratchethack]

With 120mm spacer I measured 125mm, 115mm (=10mm) and 102 (=23mm) respectively.

Thanks, Gio. Since I'm in the middle of cutting spacers right now, this is helpful for comparison purposes as I dial things in.

 

Using your figures with the 120 mm spacer, your laden sag at 23 mm translates to 18.4%. Your unladen sag at 10 mm translates to 8%.

 

My target sag figures with my new springs are 33% (38 mm) laden, and 18% (21 mm) unladen. This is a "target" that if I can get close, I figure will yield more ideal fork performance, only achievable with considerably stiffer springs than stock for my weight (175 lb. without leathers). Of course as always, YMMV.

 

My "First slice" at shortening spacers wasn't short enough. Off to the workshop now for another round of PVC mayhem.

 

Before I make my next pile of plastic sawdust, any comments? Gio? Brian? Dave? Anybody?