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Discussion Starter #1
The manual procedure to change fork oil is to remove the whole fork, drain oil and pump fork to remove residual oil.

I stumbled across a method of just removing the fork cap bolt and sucking the oil out of the fork, then replacing the amount you removed.

The only downsides I can think of is it isn't a complete drain as you don't pump the forks (so probably 10% oil remains?) and you can't inspect the internals of the forks.

What do you guys think of this method? Is it a complete waste of time or an easy way to keep fork oil relatively fresh?
 

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Maybe not perfect, but the amount that's left isn't significant IMO. Better to have a higher quality fork oil of the proper weight (OEM oils are usually overly thin) mixed with a small amount of OEM oil than not changing it if pulling the forks is a no-go.

It's not going to hurt anything.

Make sure you are using Fork Oil, most likely 15W or close.
 

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So the factory recommended 10W is too thin? I was going to get Motul 10W fork oil.
Not sure, but most of the time suspension tuners seem to recommend 15W if you do any amount of "sport" riding.

20W seems more for the track unless you are running extra heavy springs due to rider weight.
 

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I would really recommend taking them off and apart completely. When I rebuilt my forks there were a good amount of metal dust at the bottom of the fork. If you just suck it out there is probably still gonna be a lot of metal left and that's going to keep causing wear. Now its probably not the end of the world but I would to prevent even more wearing of the bushings and fork tube.

I also upgraded to Motul 15W which definitely helped the damping a bit but not as much as I was hoping. I would look at the 20W.
 

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I was just at the Honda dealer picking up an oil filter and asked about fork oil. They said the stock fork oil is 5W and if I wanted to go higher they recommended 7.5W.


Now I'm going to have to go do a little reading in the factory manual.
 

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I would really recommend taking them off and apart completely. When I rebuilt my forks there were a good amount of metal dust at the bottom of the fork. If you just suck it out there is probably still gonna be a lot of metal left and that's going to keep causing wear. Now its probably not the end of the world but I would to prevent even more wearing of the bushings and fork tube.

I also upgraded to Motul 15W which definitely helped the damping a bit but not as much as I was hoping. I would look at the 20W.
Depending on the age and mileage, there may be some gunk sitting in the bottom of the forks. Removing and flushing them out is the best if possible.

For fork oil weight it's going to depend on your riding style and weight. Many mid-range bikes have very weak fork springs, and can benefit from proper rate springs for your size and riding style. My SV650 had notoriously weak fork springs, and replacing them with the proper rate springs and correct fork oil made a big difference. I also swapped the junk rear shock for a correct Ohlins unit as well. Stock suspension is usually barely adequate for anything except moderate riding, so if you like to ride a little quicker it's worth looking into better options.

As far as the oil, search around and see what people are using. Sonic Springs has a calculator on their site that tells the original spring rates of numerous cycles and can calculate the optimum rate for you. They may also be able to recommend the correct weight for oil. You can also check what racers are using, and step down a notch from there.
 

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I would never change fork oil without removing forks in order to completely drain the old oil. It is surprising how much residue from wear is in the oil. This needs cleaning out. The muck you see is metal dust and oil seal dust - not good to have in your clean, new oil.
 

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Discussion Starter #9
I end up just doing the suck out method, and pulled out this terrible metallic black solution. I then put back the same amount of fresh oil. Next time I may take the forks off, or if the seals need replacing.

Still way better than leaving the old oil in.

(New oil is on the left)
 

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Not perfect, but an improvement no doubt.

You could do another quick change again next season. I'd pump the forks numerous times to mix the contaminants before siphoning.

Not a big project, and fork oil in those amounts is reasonably inexpensive.
 

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I end up just doing the suck out method, and pulled out this terrible metallic black solution. I then put back the same amount of fresh oil. Next time I may take the forks off, or if the seals need replacing.

Still way better than leaving the old oil in.

(New oil is on the left)
What was your mileage at the time of change? Have 36k+ miles on mine and will likely do a change this spring/summer.
 

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A bit over 60,000km (about 36k Miles), if I had of known it was supposed to be changed I would have done it way earlier. I've never had to change fork seals.
To be fair it's not in the maintenance schedule. Usually it just stays in there until a seal fails, then since the forks have to come out anyway the fluid just gets changed.
 

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I successfully did what was outlined in this video, but he leaves a few steps out.
1. Only do one fork at a time, otherwise front end will go down and will be very hard to compress springs enough to put caps back on!!!!
Best solution is you need to elevate the front wheel off the ground and unload it

2. Each fork takes 11.2 oz +/- .08 oz fluid with spring removed (I used 1qt/32oz Motul 15W from Amazon)

3. I created my own syringe kit by ordering a large syringe from Amazon

Attached a 3/8" OD clear to it - used that to draw old fluid out

When I got everything I could that way, I then attached a 1/4" OD line to that and stuck it down deeper into the fork to get the rest out

4. The manual says the fluid, with forks compressed should be 5.9" from the top


Best method would probably be to remove the forks, but I wanted to try this shortcut method to see how it works.
 
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