fork oil change questions

[gonzosc1]

I'm wanting to hear from others that had changed the weight of their fork oil.
09 c14 I got new in 10 as a left over 13K miles now and starting to notice the difference in feel of the front end. when I first got the bike 3 clicks out from full in was the ticket. cornered great and all. but now at that setting it has a fair amount of bounce and wanders wide coming out of curves while not holding the compression long enough.
 set at full in now and it rides great again but I know this won't last long. looked at everything and no leaks that I can see.

my riding is  65-35 with twisties being the main balance of that so it gets more hard riding then commuter driving. I'm 185lbs so springs are in the right area for me and don't see a need to change them.

what is the cost to get the oil changed?
what weight oil should I use?

[Pokey]

Free labor if you do it yourself.

[Taff]

I'm wanting to hear from others that had changed the weight of their fork oil.
09 c14 I got new in 10 as a left over 13K miles now and starting to notice the difference in feel of the front end. when I first got the bike 3 clicks out from full in was the ticket. cornered great and all. but now at that setting it has a fair amount of bounce and wanders wide coming out of curves while not holding the compression long enough.
 set at full in now and it rides great again but I know this won't last long. looked at everything and no leaks that I can see.

my riding is  65-35 with twisties being the main balance of that so it gets more hard riding then commuter driving. I'm 185lbs so springs are in the right area for me and don't see a need to change them.

what is the cost to get the oil changed?
what weight oil should I use?

The cost to get the oil changed depends if you do it yourself or get a dealer to do it. Always get a quote and ask to see the Kawasaki repair manual labor time for approximate cost. Add in parts, and tax if applicable.

2009 C14 Front fork oil: Kayaba 01 (KHL15-10) or equivalent SAE 5W.
Amount per side: When changing oil approximately 445 mL (15.0 US Oz)

After disassembly and completely dry: 526 +/- 4 mL (17.8 +/- 0.14 US oz)

Jon.

[gonzosc1]

well I know on the old board someone or a few changed the weight of the fork oil. was wondering what they used.  thinking maybe I would get a little longer lifespan out of it.  wouldn't mind doing it myself but don't have the tools for that.

[Taff]

well I know on the old board someone or a few changed the weight of the fork oil. was wondering what they used.  thinking maybe I would get a little longer lifespan out of it.  wouldn't mind doing it myself but don't have the tools for that.

Yes you are correct, as I read that too about the the change in weight of the fork oil.
My advice is to find a shop that deals in suspension upgrades for motorcycles and call them.

As a matter of interest, I have 5W oil on another sport touring bike with upgraded suspension which uses 5W oil as the valves in the forks only like this 5W oil.
Correct spring rates for rider weight etc is probably the most important part of the fork leg and is often ignored. Next is pre-load and rebound set up after the oil and component change.

Hope it works out for you.

Jon.

[rcannon409]

The cartridge forks dont work well when you get too far from the original wt oil.  You can sometimes get by with using 2.5 wt, or 7.5, but too far away from the stock weight and they get really harsh and feel like they are locked up.  You cannot really adjust the harshness out since the stock adjustors work more like bypass valves and dont allow much tuning range.

[gonzosc1]

The cartridge forks dont work well when you get too far from the original wt oil.  You can sometimes get by with using 2.5 wt, or 7.5, but too far away from the stock weight and they get really harsh and feel like they are locked up.  You cannot really adjust the harshness out since the stock adjustors work more like bypass valves and dont allow much tuning range.

ok that makes sense, it just seems like 13k miles is a bit early to notice a big change like I have noticed.  for city riding I can set it at 2 clicks out from full in and its acceptable. but hard twisty riding I have to go full in or she just springs back up on me to fast causing me to run wide on the exit. 

rechecked sag last night with friends and I'm still rock solid on spring adjustment. has not changed since I first set it up 12k ago. set at 9mm showing on adjusters. I guess I could go down to 8-7mm just to see what happens

 other then doing a fork swap I'll just have to live with an oil change with stock oil.

[Fretka]

Changing fork oil will give you much less compliance (small stutter bumps) and make the bike much less comfy.
Always change springs first.
Put a zip tie on the fork and see how much travel you are using and adjust preload from there.

[gonzosc1]

Changing fork oil will give you much less compliance (small stutter bumps) and make the bike much less comfy.
Always change springs first.
Put a zip tie on the fork and see how much travel you are using and adjust preload from there.

I could do that again. I used the zip ties on my first setup and came up after adjustments at 9mm showing on the adjuster. but rechecked sag again the other day and it measured at the same distance as my first setup.
 
I don't see how the springs would be affected only after 13k and i'm well within the weight(185lbs) for the stock springs. the only other thing I can think of to do would be to do a full setup on it again as I just put tires on it 1k ago. maybe try totally different sag settings.
 used a mixed match set of tires, maybe the tires I went with don't agree with the C14 in that combo. PR2 rear and Connti motion front. its my first PR2 but have had 3-4 connti motions already on it before.

[Fretka]

So you say the front rebound is too fast but you still have some travel left in the forks, Right? Set front dynamic sag so that you just use up front travel with the most braking you use. Use the zip-tie to measure travel and spring preload to set it.
To deal with understeer (push) I would then look at speeding up (less rebound) the rear shock and set dynamic sag at about 32 mm. using the remote spring knob.
If that does not do it you might get the forks shimmed (valved) but I don't think you will like what heavier oil will do to the compliance of the ride.

Just my 2 cents...

[gonzosc1]

ok, i'll try that on the rear. I'm at 35-36mm but I do have the rebound set kind of slow. its about 1/2-3/4 of a turn from full in.

thinkin about the front zip ties. thats the way I did it. but just thought about something that may make a difference.  I'm a big duel braker using front and rear together.
 wonder if setting my front sag while braking in the manner would have caused me to not set it correctly.  that maybe the load did not shift to the front enough from using the rear brakes while taking measurements of the front ummmm! then when I hit the twisties it shows more..
 maybe?

ill redo it all this weekend

[Fretka]

General ballpark numbers for everyone would be about 40-45mm front dynamic sag, 32-36 mm at the rear. this is set with you and all your gear sitting on the bike with feet on the pegs and someone holding the bike up for you.

FRONT FORK SETTINGS

Preload is set by the screw adjuster located at the top of the forks and both sides must be set the same, turn in for more preload and conversely.

Put a zip tie on the stanchion (upper part of fork sliding surface) and pull the bike (forks) and zip tie to it's fully extended position (up), sit on the bike as above which will compress the forks and zip tie. The bike must be upright and held by someone while you take measurements. Then take a measurement from the top of the ziptie to the rubber seal bottom surface when the forks are fully extended up again.

This should be in the 40-45mmm. range.

This dynamic sag # can be adjusted using spring preload found at the top of the forks. Leave the zip on forever and after riding it will tell you how much of the fork travel you are using. If it is bottomed out, dial in a little preload, if it is not pushed near the bottom (fully compressed) then dial out some preload. You want the zip to be almost to the bottom of the stanchion which means you are using the full amount of fork travel available.

Rebound settings for the fork should let the forks pop back up (after compressing them) in about 3/4 second to one second at most...... but definitely not BOING! (too fast). Rebound is set using the screw at the bottom of the forks. I think turn the screw in for more rebound and conversely.......

Too fast a rebound will cause the bike to turn wide or push as you know. This info above pertains to the front only.

REAR SHOCK SETTINGS

Rear preload is set by using the remote knob on the left side of the bike. Rebound is set by using the screw found at the bottom of the shock body. Turn in for more dampening and conversely.

Lift the rear to it's highest position and measure that by using any point on the bike (turn signal) to the ground. climb on again and with feet on the pegs and all gear and helmet on,  have someone measure that same way as above, subtract the two and you have your rear dynamic sag, (32-36 mm). Use spring preload knob to set this figure.

Raising the rear of the bike by rear spring preload will make the bike turn faster/easier and less preload, conversely.

 Less rear rebound (faster boing or recovery back upwards) will allow the bike to turn faster/ easier, also,  by the rear of the bike being higher than the front( during a corner) and thus shortening the wheelbase.
Too much rebound dampening will slow the rear recovery time and make the bike run wide in the turns.

Ideally the rear should recover (up) slightly faster than the front and this is set by the rebound screw at the bottom of the shock body. Less rebound= faster recovery= tighter turns (applies to the rear only).

 When adding additional weight or passengers the preload on both front and back can be increased by say one full turn in of both fork and shock. (This is a guesstimate). Remember to check tire pressures constantly with higher pressures for added weight.

I suspect that trying to describe this process I have made a confusing mess but If you have any ? let me know. We can also go into tires and pressures if anyone wants to.

Fretka

[gonzosc1]

wow, thats the first time I've seen such a big difference in sag settings from front to rear.

General ballpark numbers for everyone would be about 40-45mm front dynamic sag, 32-36 mm at the rear. this is set with you and all your gear sitting on the bike with feet on the pegs and someone holding the bike up for you.

FRONT FORK SETTINGS

Preload is set by the screw adjuster located at the top of the forks and both sides must be set the same, turn in for more preload and conversely.

Put a zip tie on the stanchion (upper part of fork sliding surface) and pull the bike (forks) and zip tie to it's fully extended position (up), sit on the bike as above which will compress the forks and zip tie. The bike must be upright and held by someone while you take measurements. Then take a measurement from the top of the ziptie to the rubber seal bottom surface when the forks are fully extended up again.

This should be in the 40-45mmm. range.

This dynamic sag # can be adjusted using spring preload found at the top of the forks. Leave the zip on forever and after riding it will tell you how much of the fork travel you are using. If it is bottomed out, dial in a little preload, if it is not pushed near the bottom (fully compressed) then dial out some preload. You want the zip to be almost to the bottom of the stanchion which means you are using the full amount of fork travel available.

Rebound settings for the fork should let the forks pop back up (after compressing them) in about 3/4 second to one second at most...... but definitely not BOING! (too fast). Rebound is set using the screw at the bottom of the forks. I think turn the screw in for more rebound and conversely.......

Too fast a rebound will cause the bike to turn wide or push as you know. This info above pertains to the front only.

REAR SHOCK SETTINGS

Rear preload is set by using the remote knob on the left side of the bike. Rebound is set by using the screw found at the bottom of the shock body. Turn in for more dampening and conversely.

Lift the rear to it's highest position and measure that by using any point on the bike (turn signal) to the ground. climb on again and with feet on the pegs and all gear and helmet on,  have someone measure that same way as above, subtract the two and you have your rear dynamic sag, (32-36 mm). Use spring preload knob to set this figure.

Raising the rear of the bike by rear spring preload will make the bike turn faster/easier and less preload, conversely.

 Less rear rebound (faster boing or recovery back upwards) will allow the bike to turn faster/ easier, also,  by the rear of the bike being higher than the front( during a corner) and thus shortening the wheelbase.
Too much rebound dampening will slow the rear recovery time and make the bike run wide in the turns.

Ideally the rear should recover (up) slightly faster than the front and this is set by the rebound screw at the bottom of the shock body. Less rebound= faster recovery= tighter turns (applies to the rear only).

 When adding additional weight or passengers the preload on both front and back can be increased by say one full turn in of both fork and shock. (This is a guesstimate). Remember to check tire pressures constantly with higher pressures for added weight.

I suspect that trying to describe this process I have made a confusing mess but If you have any ? let me know. We can also go into tires and pressures if anyone wants to.

Fretka

[Fretka]

wow, thats the first time I've seen such a big difference in sag settings from front to rear.

Ohlins calls for 45 in most of their manuals which seems to me a bit much but they surely know what they are doing!

These are the numbers I use in all my bikes, from a Ducati 999R with slicks, my BMW rr1000 and the Connie. These figures are pretty much universal for all similarly equipped road bikes.