Marz Fork oil change & setting AIR GAP!

[Guest ratchethack]

Show me a 10 year old vehicle that has always had ALL the OEM items done every time. 

I'll be prepared to do just that (or damned close to it by my service record) in 4 more years......

[Guest Nogbad]

Now THAT'S ANAL!

[Guest ratchethack]

Provided the fork design keeps the dirt and moisture out, and allows any wear debris to descend to stagnant areas in the base of the slider oil life should be indefinite from a viscosity stability and corrosion standpoint.

We'll certainly disagree on this. I'd expect extreme shear forces in the operation of forks. While not thermally stressful, the conditions under which fork fluid are stressed are probably among the highest possible circumstances for shear stresses and long-chain hydrocarbon breakage - hence the development in recent years of specialty synthetic fork oils such as CARTRIDGE FORK FLUID. I suggest that in use, a normal, violently vibrating and pounding USD fork lower-end, along with the rest of the unsprung suspension mass, more closely resembles a paint-shaker than a "stagnant area" that would either keep damaging particles out of suspension in the fluid or at all sealed off from critical load-bearing bushings and sliders. But thats' just me......

Most car engines go for over 12000 miles between changes with synthetic oils. 12000 mile fork oil changes are probably a waste of good oil.

Forks are neither engines, nor do they have lubrication requirements remotely similar to that of engines. ATF has long been used in damper-rod forks with good results. Would you use ATF in your crankcase?

Now THAT'S ANAL! 

So you think maintenance by the Guzzi service manual is "anal", eh? Hmmmmmmmmmmm...... I reckon I just don't know how to properly "sweat my assets" then...........

[Guest Nogbad]

Ratchet, it is only the polymer VI improvers in multigrade oils that are cracked by thermal and mechanical stresses. You can't crack the base oil molecules like that. Fork oil doesn't have VI improvers in it. It's a straight oil, whether synthetic ester based like ATF or single weight mineral oil.

 

I have never noticed my fork legs get much more than vaguely warm and I can't see for the life of me where these extreme loadings come from. The sliders are huge bearing areas for the applied load compared with a big end for example and there is no contamination from combustion products etc.

 

The forks only absorb relatively low frequency wheel movement. Virtually all of the high frequency road undulations are taken care of by the tyre. Paint shaker - Nah. Even if you put fork oil in a paint shaker for 10 years it would come out the same viscosity as it went in.

 

If what you said was true, how come car shocks last 100,000+ miles on the same fluid?

 

The change out requirement can only be because of the breathing in of moist air, wear debris from the springs or dirt / bug ingress. By far the most serious of those is wear on the spring. It's nothing to do with oil degredation.

[Guest ratchethack]

Ratchet, it is only the polymer VI improvers in multigrade oils that are cracked by thermal and mechanical stresses. You can't crack the base oil molecules like that.

Well, Noggy, I beg you differ. Now I'm gonna hafta go to work....

 

Maybe we can turn this thread into a FORK OIL thread?!?!?!

 

To clarify a point you seemed to have missed above, to my way of thinking, the "paint shaker" action of fork lowers would tend to keep particle contaminants that would settle to the bottom of forks while not in use suspended in the fluid when the bike is ridden, circulating it in the oil and transporting metallic swarf and other sediment to critical bearing areas, as well as through critically important orifices of the damping valves. I don't think there's any reasonable argument against the thought that this is not a good thing, and something that's rightfully minimized by the suggested service intervals.....

 

FORK OIL BREAKDOWN

 

“First off, all oil breaks down. That generally will include basestocks and additives (actually additives are really "used up" rather than broken down...).” While it seems to be true that “Synthetics designed from the right combination of basestocks and additives can last indefinitely with the right filtration system”, (SOURCE: Michael Kaufman, author, The Motor Oil Bible, copyright 2000), Guzzi specifies dino oil (10 wt.) for the Marz 40 mm fork. Dino oil begins to deteriorate almost immediately.

 

“Once [oil] has sheared beyond a specific point it will not revert back to it’s base structure when it cools down and the shear forces have ceased.” (SOURCE: copyright 2000-2006 Performance Oil Technology. L.L.C.)

 

1. INCREASED AERATION - the effects:

 

- loss of protection at bearing surfaces

 

2. OIL ADDITIVE DEPLETION - the effects:

 

- oxidation

- thermal and compressive base oil degradation

- hydrolysis

 

SOURCE: Mark Barnes, Noria Corporation, "The Lowdown on Oil Breakdown". Practicing Oil Analysis Magazine. May 2003, http://www.practicingoilanalysis.com/artic...oup=OilAnalysis

 

3. PARTICLE CONTAMINATION - the effects:

 

- surface removal

- restriction of oil flow

- increased consumption of lubricant

- higher energy consumption

 

SOURCE: Jim Fitch, “A Much Closer Look at Particle Contamination”, Practicing Oil Analysis Magazine, Sept. ’05, http://www.practicingoilanalysis.com/artic...oup=OilAnalysis

 

I have no idea why automotive shocks "last" up to 100K miles. I'm not sure how relevant this is to a Marz 40 mm USD fork. I suspect that Guzzi had a reason to specify 12K mi or 1 year replacement interval, and that the reason wasn't either a selling point, a frivolous suggestion, or a joke.

 

Nog, if you're going to persist in arguing against Guzzi OEM service specifications, that may be more than satisfactory for yourself, but again - I would not advise anyone reading this to use your arguments (such as they are) for justification for negligence in maintenance of their Guzzi according to the service manual.

 

BAA, TJM, & YMMV

[Guest Nogbad]

As with your GW arguments you persist in using irrelevant articles about a different situation to support your argument.

 

As far as I can see, all these citations apply to high temperature high stress applications far removed from a fork.

 

I can accept to an extent the argument that particle contamination could be an issue in a fork, but the rest is irrelevant.

 

You place a title "Fork oil breakdown" in bold, and follow it with a quotation from engine oil studies. This heading has nothing to do with the subsequent text.

 

Sorry, you should apply for a job as a political press secretary, spin doctor or other propagandist.

 

Oh yes, clearly if the Guzzi manual says change the fork oil God has decreed it. It doesn't say to lube the cush drive but you do that. So, just like religionists, you pick and choose which bits of the bible to enforce, and then make up new bits so you can be considered "in the know". Weird. Guzzi fettling as Gnosticism!

[Guest ratchethack]

As with your GW arguments you persist in using irrelevant articles about a different situation to support your argument.

SIR NOGGY! I do b'lieve you've got the hedgehog in y'er codpeice again!

 

What part of this quote,

 

“First off, all oil breaks down. That generally will include basestocks and additives (actually additives are really "used up" rather than broken down...).”

 

- do you seem to be having trouble with, then??

 

Though the references address motor oil, I've used them entirely properly as applicable to fork oil, and in context with each reference - as they would be with ANY oil used anywhere in a motorcycle.

 

Please indicate exactly where you find any irrelevance in my references, either this thread or any other? Absent any explicit examples, I'll ignore your entirely baseless remark.

[Guest Nogbad]

I'm kind of likely to give up soon.

 

The reason these references are irrelevant is that engine oil is repeatedly heated close to its breakdown temperature, hammered hundreds of times a second with impact loading, sheared through the oil pump and subjected to combustion products and fuel vapour.

 

That's why it breaks down.

 

Fork oil doesn't experience this. Engine oil is living in Mogadishu. Fork oil is vacationing in Hampton Beach.

 

So I disagree that ANY oil in a motorcycle breaks down. Oh dear, I better put a new top up can under the seat every 12000 miles in case the vibration and the heat from my sorry ass has caused it to break down. After all, that oil was "on" my motorcycle!

[Guest ratchethack]

First, I note that you have not answered my question with an exact mention of any irrelevance in any reference I have provided here or elsewhere, but instead you've stuck with a blanket statement. Your contention is apparently that fork oil is somehow immune from the many causes of oil breakdown that I've listed. Let's explore this, shall we?

The reason these references are irrelevant is that engine oil is repeatedly heated close to its breakdown temperature, hammered hundreds of times a second with impact loading, sheared through the oil pump and subjected to combustion products and fuel vapour.

 

That's why it breaks down.

 

...I disagree that ANY oil in a motorcycle breaks down.

Nog, your simplistic assertion that the heat of combustion is the only cause of oil breakdown is at odds with the facts, and I would challenge you to back this up with any evidence that non-crankcase oils are immune to breakdown. Heat from combustion in an engine is only ONE of the many causes of oil breakdown of motor oil, as I think I've fairly thoroughly illustrated with the sources I've provided.

 

If you mean to say that increased aeration, additive depletion (in the case of fork oil this would include anti-stiction friction modifiers and anti-foaming agents, among others), oxidation, thermal and compressive base oil degradation, hydrolysis, surface removal, restriction of oil flow, increased consumption of lubricant, higher energy consumption, etc., as categorically listed above are all caused by the heat of combustion, I believe that you are plainly and self-evidently incorrect. All of the above conditions (including significant heat that damages oil) are present in every case where oil is used on a motorcycle.

 

At the interface of bushing and slider in a fork, immense pressures occur, which create immense heat at the molecular level. Metal-to-metal contact also causes immense heat due to friction at the interface of bushing and slider. This heat is relatively small in terms of absolute energy content, but it is nonetheless very significant in terms of temperature at the molecular level, where the damage to the oil occurs, even though the high temperatures are rapidly diffused in surrounding oil. If you doubt friction occurs in a fork, how then would you explain the metallic swarf that you're about to discover in the bottom of your sliders?

So I disagree that ANY oil in a motorcycle breaks down. Oh dear, I better put a new top up can under the seat every 12000 miles in case the vibration and the heat from my sorry ass has caused it to break down. After all, that oil was "on" my motorcycle!

Oh, leave us not be so silly, my dearest Noggy! I have not suggested that vibration causes oil breakdown, as I have already noted once. That notion has been entirely your own. If you actually look at the words I've used, I've only referred to places where oil is used on a motorcycle - not where it might be transported like groceries - good grief!

 

Well, Nog - I reckon you've barked yourself up a fairly tall tree here. You've presented a case (however poorly IMHO ) for not replacing oils unless they are crankcase oil. Since this is at considerable odds with the service manual, I reckon the burden of justification has fallen upon you. I certainly haven't seen a convincing argument from you that squares with what I know - or with the sources I've brought to this little debate. I didn't spend a lot of time researching oil breakdown, but I believe you know I could find a great deal more backup of the same kind that refutes your assertion.

 

If you really believe what you're saying here - that the Guzzi service manual's suggested replacement interval for oils except for crankcase oil is "anal" and presumably superflous, tell me - would you suggest that it's ever a good idea to change gearbox oil or bevel drive oil? Why then would you ever service your forks, if your objective in doing so is not to "prove" your preconceived idea that fork oil doesn't break down? When having a dealer or other service provider service your bikes, why not have them skip all oil changes except for the engine?

 

Enquiring minds just gotta know.....

[Guest Nogbad]

The metallic swarf in the bottom of the sliders is usually from the spring scraping the inside of the tube, given the evident spring wear I have seen before. I never said the oil shouldn't be changed. I just think that other than debris, oil breakdown is not likely to be even slightly significant. If it wasn't too much trouble, stirring your old fork oil up with some silica gel to get any water out, and then filtering it to remove that and any wear particles would leave you with a fluid you could happily put right back in.

 

What is so special about a Guzzi? Ask Red-Line and they will say that the life of something like shockproof heavy in the Guzzi gearbox and bevel is indefinite unless it gets contaminated through a leaking breather. So, no sign of oil breakdown there then eh!

 

Take cars as an example. Modern cars have ATF and gearbox oil that is expected to last more or less the life of the vehicle. Shock absorber fluid too.

 

Sorry, but what you say flies in the face of all the non-Guzzi evidence.

[Guest ratchethack]

Sorry, but what you say flies in the face of all the non-Guzzi evidence.

I've gotta say that I've found this entire discussion most remarkable.

 

I've heard some amazingly convoluted justifications for negligence in the maintenance of motorcycles in my time, but I gotta give you credit here - yours has been the most persistent - even in the face of contrary evidence and independent oil expertise which you've not as much as attempted to address except in the most general and indirect ways.

 

I note again that you're still not answering my questions.

 

But just answer this one question, please our dearest Sir Nog, of the Absolutely No Non-engine Fluid Replacement Brigade:

 

I'm seriously baffled by your contradiction! (once again with FEEEEELING) - Why would YOU change your fork oil as you've indicated y'er planning to do at the upcoming first 12K mile suggested interval?

 

Enquiring minds just gotta know........

[Guest Nogbad]

I've gotta say that I've found this entire discussion most remarkable.

 

Glad you are enjoying it anyway.

 

I've heard some amazingly convoluted justifications for negligence in the maintenance of motorcycles in my time, but I gotta give you credit here - yours has been the most persistent - even in the face of contrary evidence and independent oil expertise which you've not as much as attempted to address except in the most general and indirect ways.

 

Well that is just complete nonsense if you don't mind. I have never denied that oil breaks down / gets moist / gets swarfy. I just don't think it particularly does in the fork. Like I said, the oil is on vacation in a pleasant place in the fork.

 

 

I note again that you're still not answering my questions.

 

You mean like you refused to do in the GW thread?

 

But just answer this one question, please our dearest Sir Nog, of the Absolutely No Non-engine Fluid Replacement Brigade:

 

I'm seriously baffled by your contradiction!  (once again with FEEEEELING) - Why would YOU change your fork oil as you've indicated y'er planning to do at the upcoming first 12K mile suggested interval?

 

Enquiring minds just gotta know........  

90028[/snapback]

 

 

Because, Dame Hatchet, I want to see what's in there, I want to check for "bug exoskeleton", moisture and swarf from the outside of the springs rubbing on the sliders. Knowledge is power.

 

Once I have this knowledge, I will decide on a suitable "condition based maintenance" regime that may or may not involve looking in there again at 24000 miles. If it's really bad in there I might look again in 6000 miles, who knows! "Scheduled maintenance" has no place in a modern "sweated assets" system. (At least, not unless the schedules are rejigged to suit use, climate etc.) Just blindly following some random Luigi system is a waste of money and oil.

[Guest ratchethack]

I want to see what's in there, I want to check for "bug exoskeleton", moisture and swarf from the outside of the springs rubbing on the sliders. Knowledge is power.

Hmmmmmmm.......but I thought you already knew exactly what to expect in there without ever having your forks apart??? As I recall, you said:

the oil is on vacation in a pleasant place in the fork.

Why disturb the comfortably loafing oil if it's sunning itself in Torremolinos, then?

who knows!

But, but.......I thought YOU did, dearest Noggy!

 

If you did find that your springs were wearing off against the sliders, and obviously contributing swarf to the oil, would this be a reason for you to shorten or lengthen your fork service interval? Is there good swarf and bad swarf?? Wicked Swarf of the West??

 

FWIW, I just took a look at my original springs. One has absolutely no evidence of contact with the sliders whatsoever, and the other has slight evidence of contact, the thin factory coating having worn off in a thin line. And yet, there was metallic swarf in both sliders. When I cleaned them out both times, I hadn't noticed any difference in amount from side to side. If there had been, I certainly would have noted it......[sigh......]

 

I've just decided this entire line of debate has lately passed amazing and ridiculous and is now deep in the just plain sad zone and now I'm sorry to've engaged in it this far. I reckon I'm done now.

[Guest Nogbad]

If despite putting in fresh oil you are still generating swarf that would suggest to me that the quality of the oil isn't making much difference to the wear rate.

 

No there is no good swarf and you would hardly expect me to say so surely.

 

I think my main point of dispute is whether conditions inside a fork are severe enough to cause chemical degredation of the fork oil in 12000 miles. I think not.

 

Torremolinos may be a bit hot which is why I sent my fork oil to the Hamptons....

[badmotogoozer]

I'm looking at changing out my springs as part of the massive overhaul coming up. Talking to Todd about the Wilbers springs...

 

He is saying Wilbers only carries one progressive spring (0.7-1.1kg) and they will spec fluid as well as air gap according to rider weight.

 

This sounds different from what you are saying...

 

comment?

 

Rj