Instructions Needed

[Guest Nogbad]

Anyone know where I can find a procedure for changing the fork oil on the Marzocchi forks. Hopefully there are some drain plugs, please don't tell me I have to take the front end of the bike apart and turn them upside down.....

[Guest ratchethack]

Sorry to be the bearer of bad news, Nogmeister. Your incredulity is shared. As soon as my new fork springs arrive, I'll dismantle my forks again for the next oil change per the long, messy procedure in the shop manual. But this time it'll be going back together with proper drain plugs drilled and tapped into the fork lowers so I don't have to do this every time I want to try another viscosity oil.

 

I suspect that changing fork oil in these forks is just the kind of relatively high-effort procedure that gets it past the perpetual "not today" threshold for 90% of Guzzi owners. I'll go further by suggesting that very few dealers actually do it at the recommended "comprehensive" service intervals (10K mi.) - I suspect this is primarily because owners don't want to pay for the labor. But just ask Carl Allison what happens when you don't do it - negligence here ain't pretty, and it ain't cheap.

 

Think of it this way: Dismantling and re-assembling your Marz forks will provide you another avenue to "become one" with your bike, and it builds character. I'd have a set of new seals on hand, "just in case". Despite great care upon re-assembly, it's simply amazing how easy it is to fold a seal back, and of course you won't know you've done it until you notice fork oil on your boot - please don't ask how I know this.

[BrianG]

  But this time it'll be going back together with proper drain plugs drilled and tapped into the fork lowers so I don't have to do this every time I want to try another viscosity oil.

 

Do let us know how that drain install goes. I've heard that the upside-down cartridge fork won't drain from the bottom, but that doesn't make a lot of sense to me, either!

[Guest ratchethack]

Hmmm.......I hadn't heard this, Brian. It doesn't make sense to me either, but will investigate. Seems to me the only possibility for oil to be retained would be part of what's left in the cartridges themselves after pumping out, which should be minimal enough that draining out from the bottom would still be a viable option. One of the main objectives of the fork oil chg is to get all the accumulated crud out of the fork lower bottoms. I reckon that tapping out the lowers at the lowest point addresses this.

 

Will advise.

[richard100t]

Please keep us posted on the drilling & tapping of the lowers. I still need to do this service, and I can probably take the forks to work & get that done there. My bike will probably have near 10k miles on it by this fall & thats probably when I'll do it.

[rocketman]

I paid my dealer to do the front fork service. Forks have to be removed for service. Inverted fork is drained from the top. Cost me $225.00. Seals were good so we didn't replace them. They were actually pretty clean inside. Did mine at 7000 miles. This is the only maintenance procedure so far I didn't want to tackle myself. You are a braver man than I if you choose to do it yourself.

 

Rocketman

[txrider]

I've done two sets of usd forks so I definitely am not an expert. But from that limited experience I can say that even turning the forks upsidedown doesn't allow all the oil out- one has to also expel oil from the cartridge by pushing the damper rod up and down so the piston can displace oil inside the rod. And since the oil change is actually more of a drain/flush/refill procedure I suggest using drain plugs would result in less than a total result. But everyone makes his own call on such.

[callison]

Well, I can tell you all from personal experience that not changing the fork oil on a regular basis can be prohibitively expensive. $500+ USD...

[Guest Nogbad]

Sorry to be the bearer of bad news, Nogmeister.  Your incredulity is shared.  As soon as my new fork springs arrive, I'll dismantle my forks again for the next oil change per the long, messy procedure in the shop manual. 

56280[/snapback]

 

Would you be able to scan and e-mail the "Long messy procedure"?

 

Incidentally, where does dirt and sludge in fork oil come from? How does it get in there at all??? I can't believe you would get enough wear debris in there after 12K miles to merit flushing the fork.

[txrider]

Would you be able to scan and e-mail the "Long messy procedure"? 

 

Incidentally, where does dirt and sludge in fork oil come from? How does it get in there at all??? I can't believe you would get enough wear debris in there after 12K miles to merit flushing the fork.

56364[/snapback]

 

No dirt and sludge, just oil darkened by metallic fines. Source of that I'm not sure but it's been there on all my fork maintenance chores and that's been 4 bikes over the last 5 years. A good possibility is spring contact with the fork inner wall.

[Guest ratchethack]

Would you be able to scan and e-mail the "Long messy procedure"? 

 

Incidentally, where does dirt and sludge in fork oil come from? How does it get in there at all??? I can't believe you would get enough wear debris in there after 12K miles to merit flushing the fork.

56364[/snapback]

Your Nogginness, I apologize for not having the ability to scan at the moment, sorry. The shop manual procedure is pretty weak and the illustrations are in the same category, anyway. Perhaps you could acquire a copy of the manual. Overall, it's a fair bit better than nothing as far as "general guidelines" go.

 

I believe my characterization of the stuff I've found coming out of the bottom of my forks the past 3 times around (once was off schedule ) was, "accumulated crud". Now Your Nogselency - lest I miss my estimation of your experience, skill, and abilities, you've been around the block a time or 2 on 2 wheels and you've done a fair share of your own maintenance work? In this case you've no doubt found a dense, metallic particulate matter in the small mass that typically accumulates at the bottoms of forks yourself at some point? This is what I've found in my Marz. As Txrider points out, it seems to be the same stuff that I've also found in the bottom of many other forks regardless of marque. I'm not exactly sure where it comes from and I don't spend a lot of time worrying about it, but I reckon it doesn't do any good in there. I'll bet I can get it out through a bottom drain plug hole along with the old oil easier than doing a complete tear-down of the front end, though.

 

BTW - In case you don't already have one, you might also see if you can get a copy of the service record book. The suggested factory service intervals seem to be quite helpful.

[Ralph Werner]

I wondered about using a small siphon tube attached to a large syringe to draw out the oil rather than disassembling everything. Baldini feels that this might work but wouldn't get all of the oil. I have to agree with him. So much for my lazy man's out!

[rocketman]

My dealer suggested doing that but I said no. I wanted to be sure all of the sludge and contaminants were removed. The sludge would be left behind with that little bit of oil that won't such out. Also, when you take them apart you can pump new oil through them to be sure all of the sludge has been removed. My two cents.

 

Rocketman

[Guest Nogbad]

I did some Norton forks and they were well full of emulsified oil and grey and brown crap. Grey from aluminium wear and brown from spring wear that had gone rusty with the wet oil. Forks worked a lot better afterwards. My MZ 250 forks on the other hand, I had those apart twice and the oil was always clean even after miles of hammer.......

 

I guess the Marz forks can't be that hard to strip. I'll just play it by ear at the 12K mark and strip 'em without the book of words.

[Guest ratchethack]

I rebuilt a set of Roadholder forks one time from a '64 Norton that were considered by some of the era to be Brit State of the Art. My memory of 'em now is that they seemed surprisingly crude even by the standards of the day. They were of dubious mileage and also had something similar to what you describe in 'em. I do remember they worked lots better after cleaning out and fitting new bushings and seals.

 

The Marz are "fairly" straightforward for the most part, except for the cartridges themselves, which admittedly still seem to be at least somewhat smarter than I am at this point. In any case, you'll be facing a choice of taking out the rods, or as they're alternately referred to in the manual, "plunger units" by taking out the socket-head bolts from the bottom of the fork lowers to get 'em out. The last time I changed out my fork oil, after separating the fork uppers from lowers I chose an "option" that evidently many others have also taken, and skipped the "Full Monty" approach and left these intact, pumping out the cartridges and letting them drain upside down overnight. I probably got another teaspoon of oil out by letting them drain overnight, not much more.

 

As has been noted, it's a little sketchy - at least in my mind - as to how and if you can actually get all the oil out, even when you go the "Full Monty" - so you never quite know what your total volume of oil is once you fill up again... Best then get as much out as you think you can, otherwise you'll just be estimating the total volume, which controls fork compression rate toward the end of the compression stroke. The manual calls for 400 ml (0,400 liter) each side. I've tried to measure the volume of what came out each time as closely as possible, but had to guess how much was in my old towels, shirt, jeans, face, hair, etc...

 

In any case, may I suggest working over a large plastic sheet and have plenty of old towels on hand on your patio, my friend. You'll no doubt use all you can get your hands on - may I also suggest not to let your wife see you do any part of this operation? She just might not quite understand...

 

Have fun. It's at least a 2-pinter (depending on your weather), but if you finish 3 - best wait until the next day to button 'er all back up.

 

BTW - I just double-checked the factory service manual. The fork oil change schedule from new is 1K miles and 6K (it lists nothing after that). So presumably it's actually every 5K after the first change. I've been using 10K intervals as a guideline.

 

Hope this helps. Maybe others with better intelligence on this can chime in?

 

EDIT: I just re-read this. Is it any wonder so many guys just have the dealer do this!? On the other hand, just how far are you willing to trust the "new trainee" in the back of the shop to do it? You know - the skinny Goth-lookin' kid with the nose rings and tattoos and the backwards ball-cap - using YOUR bike to "learn on". S'pose he'll get it right!? I'll just do it myself, thank you very much...