1996 Sport : changing fork oil for the first time

[WaiNYC]

Yes, you read it right. My 1996 Skorpion Sport has never had a fork oil change in 2.5 decades. All my fault and neglect. It's almost a capital offense. One explanation is that the bike was in storage in 2/3 of those years. And it has less than 6000 miles. Almost a new bike but with bad fork oil (all other fluids are current )

So far there is no oil leak. And bec of the low mileage, I figure that there is little to no debris inside the fork tubes, and I believe/hope/assume only rubber parts are degraded.

Because of time constraints, I am gonna change fork oil ASAP, and then later when time allows overhaul the front fork.

This is my first time changing fork oil. So my newbie questions are:

1) For the oil change, is the drain bolt gasket ring the only seal that need to change?
2) Assuming that only rubber parts are bad, what parts will I need for the overhaul project later on?
3) Where can I get these parts other than from Grahams? And how do I specify them if the stock list does not include MZ?

As always, thanks for all the help.

[Puffs]

Sorry, don't know the fork on that bike, nor any details thereof, but after just 6k miles I'd say there isn't such a big hurry to change that fork oil. Fork oil doesn't get hot, so hardly degrades, it's only deposits due to wear that cause the need for maintenance, and that's very much mileage dependent, not so much time dependent. And the viton used for the seals should also still be fine.

I'd just ride the bike.

[WaiNYC]

Sorry, don't know the fork on that bike, nor any details thereof, but after just 6k miles I'd say there isn't such a big hurry to change that fork oil. Fork oil doesn't get hot, so hardly degrades, it's only deposits due to wear that cause the need for maintenance, and that's very much mileage dependent, not so much time dependent. And the viton used for the seals should also still be fine.

I'd just ride the bike.

Thanks for the input, @Puffs, and it's a good point. But why not do it anyways? it's good ole nerdy fun to work on bikes and I'm still learning.

Speaking of which, Grahams suggests the following for changing the oil:

1. Remove the forks from the bike
2. Remove the top nut
3. Turn the forks upside down to drain.
4. Replace the fork oil with 10w and 350ml per fork.

But all the generic how-to manuals I've read instruct draining from the bottom, and topping up from above. No removal of forks. What is the community's experience re fork oil change on the Sport?

Sorry again for asking your holding my hand thru this. Thanks a million.

[breakwellmz]

I took mine out and poured the oil out followed by flushing. Mine was ten years/20,000 miles old.
I probably wouldn`t have bothered if i wasn`t fitting progressive fork springs, the old oil didn`t look `old`.

[WaiNYC]

Thanks @breakwellmz for sharing the experience.

I just saw oil from underneath the left tube. This is the second drop that I've seen, so I was wrong about not having leaks. There is, albeit slowly.

Has anyone simply done the oil change with draining from bottom and adding at top? or must I remove the fork tubes?

[breakwellmz]

Sounds like you need to replace a fork seal!

[WaiNYC]

Sounds like you need to replace a fork seal!

You're right... Any alternative source in US for getting the seals other than Grahams?

[WaiNYC]

Sounds like you need to replace a fork seal!

You're right... Any alternative source in US for getting the seals other than Grahams?

I know the MZ uses many standard parts. So I suppose I only need to know the seal and the dust cover's specs... but I don't

[breakwellmz]

Wasn`t difficult to find really!

https://www.ebay.com/itm/MZ-MUZ-Skorpio ... 1243642794

[WaiNYC]

Wasn`t difficult to find really!

https://www.ebay.com/itm/MZ-MUZ-Skorpio ... 1243642794

Oh, thanks so much @breakwellmz

I also stumbled on this webpage, with a host of mechanic and parts specs on the Skorpion, including the fork seal, and instructions for changing fork oil ! which is similar to what Grahams has advised me:

http://www.philadelphiariders.com/wiki/ ... p/MZ_Notes

Maybe useful for the community here?

[DAVID THOMPSON]

i drain the forks using a piece of car brake line and a Mity vacuum pump
use a catch bottle to keep it out of the pump
a rinse could be used but make sure it does not do a job on the seal rubber
the reason for no drain is safety oil stays in there unless you take it out

also people cant do you in by draining your forks in the dark of the night
to recycle it in to there bike

[Puffs]

Oil on the front brake can be a bad surprise. If it leaks you have to replace the seals.

Many forks have a drain bolt at the bottom, maybe the parts list (http://www.miraculis.de/aw/download/mz/skorpe.zip, section 10) helps. Watch out: screw 14 might actually also hold the damper assy, and unscrewing it might give problems - I don't know. I do know that in several damping assy's you cannot suck the oil from the top, so taking the tubes out, shake them vigorously & drain by inverting & pumping always works.

As you need to replace the seals (always on both sides), you need to take them out anyway. Good luck!

[WaiNYC]

Thanks @David and @Puffs for your inputs.

Just an update: I "lifted" the dust covers of the two tubes. The right tube has rust inside. While the left is alright, there are oil marks on the tube itself:

Right tube:

Right fork tube, rust inside dust cover

Left tube:

Oil residue on left fork tube surface

Left fork tube

Looks like the stopping springs also need to be replaced

[Puffs]

Thanks for the update.
I cannot see very well, but pitted corrosion on the stanchions will wear the seals down, and that may cause leaks. Absent of that, just clean & new seals + oil.

A bit of rust on that seal retaining spring need not be an issue, if it is still strong enough you might re-use it. But it does indicate it had some humid years...