Just changed my fork oil

Just finished changing my fork oil. I have never done this before on any bike I have owned, I just recently learned you’re supposed to do it once a year. Since I just recently adjusted suspension sag and rear rebound which made a huge difference, I thought why not finish the job? The bike only has 11k miles on it, but it’s a 2009 and I doubt it’s ever been done.

It was straightforward: remove front wheel, loosen pinch bolts and the fork tubes slide right out of the triple tree. Then you can unscrew the top cap (loosen them before disassembling), drain the old oil, and replace with fresh stuff.

I haven’t done a test ride yet to see if it feels any different, but I’m sure the placebo effect will reward my efforts with great feelings of new smoothness and handling excellence

wasn't as bad as expected then...
enjoy the new smoothness and handling excellence that goes with doing your own servicing

- just as long as you put everything back, torqued it up, and don't have a few nuts and bits left over

How much oil came out? Was it about what should have?

tvboy wrote:

How much oil came out? Was it about what should have?

Good question, which I should have asked myself earlier. I drained as much as I could and replaced with the same amount that came out, but didn't actually look at the spec to see the total volume.

I got around 350ml out of it (and replaced the same amount), but I just checked the service manual and the total is 520. So I obviously didn't drain it very thoroughly. Hopefully replacing 2/3 of it with fresh oil is still an improvement. I guess you need to completely disassemble the fork to get all the oil out.

I was very curious about it because there is a suspension guru named Dave Moss. He says it's impossible to get it all out unless you disassemble the entire tube.
His advice is to remove what you can then put in the same amount you got out unless you got out too much. Doing my fork oil is on my list of projects because I'm only getting about 3-3.25 inches of travel and our Showa forks should be getting 4.25 inches. Everything I've read indicates too much oil will prevent full travel so it's got me wondering.

About your 350ml, maybe it was under-filled at some point?

tvboy wrote:

I was very curious about it because there is a suspension guru named Dave Moss. He says it's impossible to get it all out unless you disassemble the entire tube.
His advise is to remove what you can then put in the same amount you got out unless you got out too much. Doing my fork oil is on my list of projects because I'm only getting about 3-3.25 inches of travel and our Showa forks should be getting 4.25 inches. Everything I've read indicates too much oil will prevent full travel so it's got me wondering.

Ah interesting, so I guess I did the right thing. The service manual shows disassembling the entire thing to drain all the oil. Maybe you'll have to do that on yours to ensure that the correct amount of oil is filled.

Quote :

About your 350ml, maybe it was under-filled at some point?

I'm assuming I just didn't drain it fully. The shock seems to have the with amount of travel; I recently set the sag and checked the total amount of motion after a ride and it seems reasonable.

What brand and weight did you put in?

tvboy wrote:

What brand and weight did you put in?

I went to my local motorcycle shop and they had Golden Spectro. I used 7.5 weight as the manual specifies.

The forks on my V7s are likely different animals, but I drain the oil, rinse with kero & drain, and refill, measuring the air gap between the top of the oil & the top of the tube. The air gap & the oil weight are supposed to be the critical factors. How different are the GRiSO forks?

Very. They are a full cartridge fork. The V7's are a primitive damper rod design.

I think someone else may have mentioned this but the fork oil viscosity grades are not consistent between brands.
So much for standards.
The 7.5wt you bought may be thicker or thinner (or the same) than what you drained out.
Let us know how it feels.

You could have done a few more steps and gotten more info and done a more complete drain.

If you remove the fork tops, and remove them and the loooong rebound adj tube, set those aside ... then you could measure your current oil height in the tubes and compare that to specs.

Then pump the inner cartridge a few times as you drain them (helps pump the oil out).

Then add the new oil back, then raise and lower the inner cartridge a few times (again) to refill the cartridge, and then get the oil height where you want it (listed in service manual).

Sounds like a lot of extra work, but not really.

But ... Dave Moss does it almost the same as you, he just pumped the forks a few times to get more oil out:


Here is another doing it short cut way


Guess they are trusting the previous service set the oil height correctly.

I watched some YouTube videos and read some stuff online, but I should have checked with you guys on here first.

But if it doesn't feel right I can do it again, it's no big deal to pull off the front wheel and pull out the shocks. Fortunately I enjoy my garage time with this bike, it's not a chore so much as a pleasant Sunday afternoon

What method did you use to support the bike while the front wheel was off?

I used the Moto Guzzi rear stand (with spools) to hold the bike straight and raise the rear a little, with a scissor lift jack-stand  under the sump to raise the front wheel, and tie-downs from the rear subframe rails to keep it steady so it can’t tip over.

(Plus the whole bike is on a lift, which raises it to a nice working height and gives something to attach the tied-downs to)

Nice set-up! I have none of those things so I will improvise

Change Fork Oil once a year................   Um, said the Bulldog never........ Maybe once a decade

Once a decade makes more sense. I got once a year from an “expert” on YouTube but I think it might be related to dirt bikes. Since my bike is a 2009, I am perfectly aligned with the once-per-decade schedule

Has never changed fork oil...

According to the service manual, every 12,500 miles:

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I have 17,000 miles on mine.

I think I will have Traxxion Dynamics do the work, and while they are at it, install some AK20 Cartridges to go with the new oil. They will replace the seals also.

Ride in appointment on May 20th

Recently replaced the dust caps and seals on mine and clearly changed the oil while I was at it. Do your research, watch a video by “Delboys Garage” [You must be registered and logged in to see this link.] Not the same forks but very similar. To change just the oil, no need to pull the tubes apart but certainly worth draining properly. Having said that, if your bike has done 17k miles, id be tempted to change seals and caps as one of mine failed at 22k miles. Saves pulling the front end off again. Found the whole job quite therapeutic, just be methodical and take your time.

So I just watched the two videos showing a fork oil change again. Both videos show USD forks (one is a 43mm Showa model) and neither video shows an oil amount over 500ccs. The Ducati video is very telling. It's a 43mm Showa tube and it requires about 440ccs of oil. He's getting full travel when he exercises the travel.The Dave Moss video shows him removing only 375ccs from that GSXR fork tube. Something isn't adding up. The MG service manual is stating our tubes take 520ccs!. I know I'm not getting full travel and I have a very firm ride to boot. Has anyone actually changed their oil and removed about 520ccs? I have a suspicion the MG service manual is just plain wrong. Should it be 420ccs? I wrote to Showa asking for some info and never got a reply. Their website says they don't reply to request for info. swell.  I'm thinking about trying 440ccs and going from there. 520ccs sounds like an awful lot of oil. Any new opinions?

When I changed my fork seals, I didn't measure the volume. I added oil to 135mm from the top. I do have Matris cartridges, so they may require a slightly different amount.

Ron added 530ml when he did his cartridges and then pulled 50ml out because it was too harsh, and it was still a bit harsh. I think your assessment is closer to the required amount. I would suggest no more than 450ml be required.