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I changed the oil in my Monoshock today. I thought it had probably served long enough and I wanted to see if having the correct quantity of new oil would affect the ride quality at all. I will check that out tomorrow, but for anyone contemplating this job I have a few observations.
Firstly it is not all that difficult a job, but does require some way to compress the shock. It also of course requires a few other basic tools. I was helped greatly by what I read in the forum archives, and by a couple articles in the Google docs section. In particular the article here .
I also reused my seal, because I am cheap and didn't feel like springing for a new one. AFAIK GL650 Seals are still available to order for around $20-$25 from Honda Dealers. (discounthondaparts.com wanted $18 plus $12 shipping.)
First thing is to get the shock out of the bike, and I was able to do this without taking the whole exhaust off. I removed the mufflers and lowered the H box a bit in order to get one of the pro-link bolts out. Since I had just serviced the pro-link two years ago everything came apart easily. The top shock mounting bolt is easily reached with a flexible socket and extension through a narrow slot between the frame and the airbox.
I cleaned the shock up and removed the rubber bellows. Here is the shock upside down in a vise:
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This shows the backup ring and the wire retaining ring:
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In order to remove the seal first I had to drive the gold colored ring down a bit so the wire retaining ring could be removed. I used a big flathead screwdriver and a big hammer to pop it down 1/8" or so. Then a dental pick to pull out the wire ring.
Now comes the fun part, getting the seal out. I tried using the press I built into the wall of my shed to do it the way the manual says, but it didn't budge. Here is the press:
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I wound up placing the shock in a bucket and applying 75# of air at the hose. With a bang the seal and most of the oil was out. I poured mineral spirits into the shock and swished it around a few times to clean out the remnants of the old oil.
I put the shock upside down into my vise and filled with oil. I used ATF (Dexron). The manual says the shock holds 669ml. I managed to get 500ml into it and had to stop because I needed room to install the bushing and seal. Reassembly was pretty much by the book except for the special fixtures on the press. I didn't have any of those so I put the seal back in with with gentle taps with a hammer and screwdriver, just like they tell you not to do! Worked fine. The above photo shows the filling of the remainder of the oil with the press.
Like the manual says, I pressed the shock with the valve removed and the end of the hose in a jar of ATF. Air bubbles come out when the shock is pressed and fluid is drawn into the shock when pressure is released. I repeated this step until no more air came out. The shock does hold 669ml or so of oil, but that amount fills the shock completely, with no air inside the shock. This is a problem because it puts the shock in hydro-lock, meaning it ain't compressing once the valve is put back on the hose! The manual says to push out 200ml of oil at this point, but I followed the recommendation of a poster on the Aussie CX/GL board and only pressed out whatever came out from one complete compression of the shock. This was right at 100ml. Less airspace above the oil should enable me to run at lower air pressure and hence have a smoother ride. I will find out tomorrow.
Firstly it is not all that difficult a job, but does require some way to compress the shock. It also of course requires a few other basic tools. I was helped greatly by what I read in the forum archives, and by a couple articles in the Google docs section. In particular the article here .
I also reused my seal, because I am cheap and didn't feel like springing for a new one. AFAIK GL650 Seals are still available to order for around $20-$25 from Honda Dealers. (discounthondaparts.com wanted $18 plus $12 shipping.)
First thing is to get the shock out of the bike, and I was able to do this without taking the whole exhaust off. I removed the mufflers and lowered the H box a bit in order to get one of the pro-link bolts out. Since I had just serviced the pro-link two years ago everything came apart easily. The top shock mounting bolt is easily reached with a flexible socket and extension through a narrow slot between the frame and the airbox.
I cleaned the shock up and removed the rubber bellows. Here is the shock upside down in a vise:
This shows the backup ring and the wire retaining ring:
In order to remove the seal first I had to drive the gold colored ring down a bit so the wire retaining ring could be removed. I used a big flathead screwdriver and a big hammer to pop it down 1/8" or so. Then a dental pick to pull out the wire ring.
Now comes the fun part, getting the seal out. I tried using the press I built into the wall of my shed to do it the way the manual says, but it didn't budge. Here is the press:
I wound up placing the shock in a bucket and applying 75# of air at the hose. With a bang the seal and most of the oil was out. I poured mineral spirits into the shock and swished it around a few times to clean out the remnants of the old oil.
I put the shock upside down into my vise and filled with oil. I used ATF (Dexron). The manual says the shock holds 669ml. I managed to get 500ml into it and had to stop because I needed room to install the bushing and seal. Reassembly was pretty much by the book except for the special fixtures on the press. I didn't have any of those so I put the seal back in with with gentle taps with a hammer and screwdriver, just like they tell you not to do! Worked fine. The above photo shows the filling of the remainder of the oil with the press.
Like the manual says, I pressed the shock with the valve removed and the end of the hose in a jar of ATF. Air bubbles come out when the shock is pressed and fluid is drawn into the shock when pressure is released. I repeated this step until no more air came out. The shock does hold 669ml or so of oil, but that amount fills the shock completely, with no air inside the shock. This is a problem because it puts the shock in hydro-lock, meaning it ain't compressing once the valve is put back on the hose! The manual says to push out 200ml of oil at this point, but I followed the recommendation of a poster on the Aussie CX/GL board and only pressed out whatever came out from one complete compression of the shock. This was right at 100ml. Less airspace above the oil should enable me to run at lower air pressure and hence have a smoother ride. I will find out tomorrow.
etc
