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Suspension Oil

stewarth

stewarth

Scooter
I just read an article in MotorCyclist talking about how road bikes don't have documented routine oil changes in the suspension system, like dirt bikes do. I'm coming up to 15k miles and this was already on my list.

Now I'm curious what others have done or plan ro do in regards to the C14?

 
I normally do mine around 10K or not long after on the factory fork oil. I then find that the replacement oil seems to work and last longer than the original factory oil. But I wouldn't think twice on changing it sooner if I was already doing something else that would make it more convenient.
 
I dumped the fork oil out of my FJR at 7500 and what came out could only be described as "Silvery Water"  I just last week dumped the oil out of the 14 (22k miles) and it wasn't as watery, but it did smell horrible and was pretty nasty. I will be doing every 10k going forward.. 

On the 14 it's not that difficult to change the oil, so there really isn't a reason not to :)

 
I'm not sure why most street bikes no longer list a change interval in the periodic maintenance chart like they used to. The C10 had a listing for changing the fork oil every 30K kilometers, or about 18K miles, and the early model C10's even had a drain screw on the side of the forks for draining the oil out, which was removed in later models.

The good news is that modern damper cartridge forks don't seem to dirty the oil as bad as the old damper rod forks did. I think a lot of the debris in the oil came from the Teflon wearing off the bushings and possibly some from the damper rod piston sealing ring and fork slider wear particles. The upside down forks in the C14 have both bushings mounted in the fork outer tube, and this coupled with the cartridge seem to result in less internal wear and cleaner fork oil. However fork oil still goes bad and can break down and change in viscosity over time just like engine oil does. I think somewhere between 18K-24K miles is probably a pretty reasonable interval to shoot for on this bike. I recently changed mine at 20K miles, and it was dirty, but not in terrible condition. I also replaced the fork seals when I changed it just because of the mileage on them, and it seemed like a good time to do it since I already had it apart. I suspect at my next fork oil change, I'll need to consider changing out the bushings as well.

I'm still a bit perplexed why manufactures no longer list an interval for changing fork oil though, as it can make a big difference in the performance of your suspension.
 
I'm planning on changing mine this winter. What weight oil has everyone been using? Anyone use the higher oil level in the second gen C-14 in the first gen models? If so any noticable change?
 
How hard is it to change the oil and what tools do you need? I don't have a service manual, but considering doing this before my next track day in Oct.

Stewart
 
Not hard, you do need some special tools like the Traxxion cartridge fork service tool kit in order to compress the spring and remove it etc...

Took me less then a half hour to get the forks out, then another 10 min to get them apart,  then let them drain for an hour or so then about an hour to reassemble and reinstall.....  and I was being lazy LOL

I will be doing it again in the next few weeks when I install the Traxxion AK20 kit I just ordered :)
 
Mad River Marc said:
Took me less then a half hour to get the forks out, then another 10 min to get them apart,  then let them drain for an hour or so then about an hour to reassemble and reinstall.....  and I was being lazy LOL
Click to expand...

Sounds more involved than I would prefer. I was hoping it was a drain,rinse,fill procedure. But if I have to remove the forks etc, then I'll just ride and leave it to the dealer to handle. Too many other priorities with the family.

Thanks for the info. Maybe when the kids move out in 20 years, or when they won't want to hang with dad in 10 years , I have more time.
 
+1 to what Marc said...

The Traxxion Dynamics fork service kit is a good value, and you can't do the service yourself without it (or something like it).

You will need a small jack (bottle type will work) to hold the front end up while working.

As for the suspension fluid to use, make sure it is rated for cartridge-style suspensions... regular "spring type" or "shock" suspension fluid is not appropriate to use with our cartridge-type forks. I think the designation is "VI" index fluid. I used the Maxima fork fluid Traxxion recommends, (Maxima 125-150, 7 wt., SUS-VI). I also have some Silkolene Pro RSF 7.5 wt. in the garage, being highly recommended by the wrenches at California Superbike School.

Also, after draining the old fluid out, use a liberal amount of "clean" parts cleaner/contact cleaner aerosol... the Next Dimension product Traxxion sells reportedly leaves less residue than other such cleaners, and my experiences with the stuff back up that claim. You really want all the internals super clean. You can't use too much of this stuff!

If you are only changing the fluid you probably won't need to worry about the fork seals, but depending on your mileage you might just want to install new seals. To do new seals yourself you will need the proper fork seal driver installation tool... Traxxion sells those too. 43mm is the size needed for the C14.

Kawasaki specifies filling the forks to 101mm of suspension fluid WITH NO SPRINGS IN PLACE.

Search the forum for discussions on installing the Traxxion AK-20 cartridge upgrade... lots of info and pix of what others have used to make fork servicing easier. Fred H's excellent Concours 14 Maintenance DVDs has the entire process presented in detail... http://www.angelridevideos.com/concours.html

When putting everything back together, a good torque wrench is your friend. On that topic, so is the service manual... pulling the front wheel, taking the brakes off the stanchions, loosening the fork clamps etc. is the easy part. Putting it all back together SAFELY and correctly is another matter. Correct torque values do count, so I wouldn't recommend attempting this service without the factory reference data. Unless you have Fred's DVDs, which have the correct values in the presentation. There are a couple of "tricks" that help with this procedure (as in what bolts to loosen first, etc.), and that is also covered in Fred's videos, as in the factory manual.
 
ProfessorKonk said:
As for the suspension fluid to use, make sure it is rated for cartridge-style suspensions... regular "spring type" or "shock" suspension fluid is not appropriate to use with our cartridge-type forks. I think the designation is "VI" index fluid. I used the Maxima fork fluid Traxxion recommends, (Maxima 125-150, 7 wt., SUS-VI). I also have some Silkolene Pro RSF 7.5 wt. in the garage, being highly recommended by the wrenches at California Superbike School.
Click to expand...

Most cartridge-style suspensions are designed to use a fork oil with a viscosity around 16.0 cSt@40degrees C and Kawasaki's Kayaba 01 oil has a viscosity of 15.6 cSt@40C.  This is normally referred to as a 5wt oil and is preferred for cartridge systems because lighter weight oils are less sensitive to temperature changes.  However any weight oil "could" be used if the valving is designed for "that" oil viscosity.

I am surprised that Traxxion recommends Maxima 125-150 because that is a heavy fork oil with a viscosity of 26.7 cST@40C but if Traxxion designed their AK-20 cartridges to use that weight oil then that is the oil viscosity that should be used for their cartridges.  Silkolene Pro RSF 7.5 has a viscosity of 37.0 cSt@40C, you can draw your own conclusions of how it would work in Kawasaki's cartridges which appear to be designed for 16.0 cSt viscosity oil.
 
mcrider007 said:
Most cartridge-style suspensions are designed to use a fork oil with a viscosity around 16.0 cSt@40degrees C and Kawasaki's Kayaba 01 oil has a viscosity of 15.6 cSt@40C.  This is normally referred to as a 5wt oil and is preferred for cartridge systems because lighter weight oils are less sensitive to temperature changes.  However any weight oil "could" be used if the valving is designed for "that" oil viscosity.

I am surprised that Traxxion recommends Maxima 125-150 because that is a heavy fork oil with a viscosity of 26.7 cST@40C but if Traxxion designed their AK-20 cartridges to use that weight oil then that is the oil viscosity that should be used for their cartridges.  Silkolene Pro RSF 7.5 has a viscosity of 37.0 cSt@40C, you can draw your own conclusions of how it would work in Kawasaki's cartridges which appear to be designed for 16.0 cSt viscosity oil.
Click to expand...

Good point 007... stock suspension + stock spec fluid = safe choice. Traxxion cartridges + "their" spec = great freakin' suspension & ride!  :beerchug:
 
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