Going to Change the fork oil

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daineseuk · #1 Post by **daineseuk** » Sun Apr 07, 2013 8:29 am

Morning

I have two weeks off while i change jobs and have decided to change the fork oil while the front wheel if off and the bobbins are being cleaned.

After searching the internet the following process seems to be the best procedure. All previous settings will be recorded.

1. While the front wheel is off and bike suspended by the Abba stand and trolley jack under the sump (stand is a priceless piece of equipment) undo the top bolts and loosen the caps, while they are held by the middle yoke bolts as i dont have a vice to grip them later on.
2. Undo all the yoke bolts and remove the fork
3. Completely back off the preload.
4. Unscrew the top cap so they are free.
5. Pull the sleave down with the two holes so that i can use 2 spanners to completely release the caps (can be awkward).
6. Place items on a clean flat surface, noting the order that the internals come out washers spring etc.
7. Tip upside down over night to drain out the old oil. Use some clean oil to flush out old if needed.
8. Once they are clean pour in 5wt oil and pump the fork holding the middle rod until no air bubbles can be seen, more oil will need to be added.
9. Remove oil while the forks are fully compressed to 115mm\8cm air gap using home made syringe and piping to correct depth.
10. Replace internals - spring etc in the correct order, and tighten the caps again.
11. Place back in yokes and torque up.

Its just from point 8 that I'm unsure. Just want to make sure the air gap is 115mm\8cm with the central rod in place as i wont be undoing the bottom bolt and any tips on bleeding\pumping the air out would be greatly appreciated.

look forward to your replies and thanks

cheers

D-Rider · #2 Post by **D-Rider** » Sun Apr 07, 2013 9:27 am

Hi and welcome

I've never done this so can't speak from experience (I just swapped my forks for a set of Ohlins at about the time I was thinking of servicing them)

Ken's site gives some info and pics - but probably nothing more than you have already established.
http://home.comcast.net/~sl_mille/fork.html

Is yours a Falco with Showa forks or Marzocchi forks? - not sure if there is any difference in procedure but section 7.8.1 of the workshop manual covers changing the fork oil. that would have been written when they fitted the showa forks but I doubt the Marzocchi's are much different.

The workshop manual and Marzocchi forks manual can be downloaded from Martin Poll's website (go for the OCR version of the workshop manual as it's searchable)

http://www.martinpoll.dk/div_april.htm

#3 Post by **mangocrazy** » Sun Apr 07, 2013 12:16 pm

I haven't stripped a set of Falco forks (yet), but I've recently disassembled a pair of RC30 forks pretty much down to the last nut and bolt. I do know that getting the tops off a set of Showas can be shall we say, challenging.

Apparently it does help immensely if you have three well-muscled arms with hands attached. Either that or a helper. And you will need some kind of pronged tool to engage in the two holes in the sleeve to pull the whole thing down far enough to get a spanner in to undo the nut that holds the top on. That's why two people (or a special tool, or both) are required.

The other thing is that unless I had stripped the whole thing down I wouldn't have believed the amount of grey sludge there is in the internals. It sticks like sh*t to everything, and had even blocked some of the ports in the compression piston. And this was a set of forks that had been overhauled less than 2000 miles previously by Revs Racing.

Also, when pumping the fork damper rod, prepare to wind up wearing a fair amount of the oil. That, or watching it drip off the ceiling...

daineseuk · #4 Post by **daineseuk** » Sun Apr 07, 2013 2:55 pm

Just noticed this is my first post on this forum so Hello.

Mine has the Showa forks and they are now nestling against the garage wall waiting to be cleaned, had to buy the biggest 32mm spanner to loosen the caps.

Had read about draining through the bottom valve but seeing as the front wheel was off decided to do it properly, at least once.

Downloading the bike manual from that link, so the worst that can happen is i have to take my cleaned forks to be refilled.

Expect mode posts over the next couple of days

cheers for you replies

daineseuk · #5 Post by **daineseuk** » Sun Apr 07, 2013 4:31 pm

Cheers D-rider,

have read and followed the section 7.8.1 and its actually quite easy, was able to pull the spring sleeve down using a strap that had a heavy duty metal S end and used a 17mm spanner to grasp the nut below the cap.

So its all draining, so will look at cleaning and topping up tomorrow. Its 118mm air gap with no internals which is something i was unsure about. Oil was a fairly cleanish cherry red.

Does anyone have any tips on flushing the forks out?

#6 Post by **mangocrazy** » Sun Apr 07, 2013 8:24 pm

If you're not intending to strip them any further, then you might buy some engine flush (I find Wurth stuff very good), pour that in and exercise the forks as much as possible. Might even be worth reassembling them and doing a spot of vigorous shaking/boinging up and down. It has to be better than leaving the old crud still in there, although if your fork oil still actually has a noticeable colour rather than sludge-grey it would probably indicate they've been looked after in the recent past.

SimonDk · #7 Post by **SimonDk** » Tue Apr 09, 2013 3:34 pm

I too expect to replace fork oil soon-ish; but the oil level numbers I have found is confusing so more input would be great...

Sources:

** Manual: 520ml = 118 mm w/o lower collar, spring rest washer, spring.

** 460 ml = 60 mm.
http://home.comcast.net/~sl_mille/fork.html
( Racetech's page for the RSV with Showa forks lists this information: Oil level: 80 mm )

** Oil quantity 455 to 460 ml each side that means oil level = 87 mm from top of the fork
http://www.apriliaforum.com/forums/show ... 8-Fork-oil, post #11-13

.. so the manual specifies more oil yet a bigger air gap than the other sources?? Both can't be right, unless some things are measured in different ways..?

daineseuk · #8 Post by **daineseuk** » Tue Apr 09, 2013 4:23 pm

Yeah, first time it seems a daunting job, but is actually really simple. Cant stress to get to the point that the forks are out and sit down with a cup of tea and read multiple times 7.8.1 in the workshop manual post above.

Have a nice clean flat area pr-prepared with some paper towel etc to put the parts down in the order they come out. The manual will make perfect sense once you start undoing the forks.

To pull down the sleeve i had a strap with a hook which i could put through the hole in the sleeve and pull down to get the spanner beneath the cap.

Its 118mm to the top slider with no internal components. Keep topping the level up as you pump the central rod, you will feel resistance increase and become uniform as the air is expelled.

Once you reach this stage, its time to set the air gap, i had a straight tube with a large syringe with a cable tie set to 118mm and just sucked the oil out till all i got was air. Then carefully replace the components etc.

I would mention that i had 1L of Motul 5w fork oil, and its wasn't enough for both so have done one leg and am waiting the other bottle to turn up, so it may be a good idea to have 2 bottles, so thinking american litre is less than uk litre. This will also give you extra to pump through and flush the forks. Luckily mine where extremely clean.

SimonDk · #9 Post by **SimonDk** » Fri Apr 12, 2013 5:14 pm

I wrote:

manual specifies more oil yet a bigger air gap than the other sources?? Both can't be right, unless

Didn't anyone else here service their fork, and can add to the info regarding the amount of oil vs. recommended oil level/air gap? TIA

HisNibbs · #10 Post by **HisNibbs** » Fri Apr 12, 2013 10:19 pm

I've replaced the oil in my Showas twice now without having to strip them down. You can just drain them, pump them a bit and then top them up. Can't remember the quantities and weight of oil but think it was the light weight (5?) oil and the volume recommended in the manual. (I do have a valve kit fitted which recommends the lighter weight oil).

The oil had been in about 3 years and 25,000 miles and I recall looked very clean.

#11 Post by **mangocrazy** » Fri Apr 12, 2013 10:35 pm

HisNibbs wrote:(I do have a valve kit fitted which recommends the lighter weight oil).

Which valve kit is that, Keith? I've got Race-tech gold valves in mine and find them a big improvement over OE

HisNibbs wrote:The oil had been in about 3 years and 25,000 miles and I recall looked very clean.

I'm rapidly coming to the conclusion that my RC30 forks hadn't been properly cleaned out when they were overhauled by suspension specialists. The oil was minging when it came out and there was sludge everywhere. Another plus for doing it yourself...

HisNibbs · #12 Post by **HisNibbs** » Sun Apr 14, 2013 9:01 pm

I also have the Race-tech gold valves but they were in when I bought the bike so I don't know any different. Feels pretty good to me too.

zoidberg · #13 Post by **zoidberg** » Tue Jul 30, 2013 7:07 pm

so this guide is ok for a Falco then?

http://home.comcast.net/~sl_mille/fork.html

#14 Post by **mangocrazy** » Tue Jul 30, 2013 8:49 pm

zoidberg wrote:so this guide is ok for a Falco then?

http://home.comcast.net/~sl_mille/fork.html

Yes, as long as you have the Showa forks; in other words if your fork tops look the same as the ones in the above link, you're good to go.

zoidberg · #15 Post by **zoidberg** » Tue Jul 30, 2013 9:01 pm

i'm pretty sure they do, how do the others look?