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Fork Oil Change

K

kman

Mini Bike
Wondering when to change out the fork oil. Manual just says to inspect periodically but general consensus for most bikes is to change out at 15-20K miles. Any thoughts or opinions? Any benefits noted when changing out the oil at that interval?

 
Cartridge forks like the C14 uses don't dirty the fork oil nearly as fast as the old damper rod style forks do.  I think you can probably extend the service interval on them to about 30K miles (or more) pretty easily. It may also depend on how you ride and how hard your suspension works. I did one with 36K miles on it a couple weeks ago, and it came out a little dirty, but not terrible. I've certainly seen worse.

However, on the flip side of the coin, the valves in cartridge forks are more sensitive to contamination. So it certainly won't hurt to change it earlier.

You will need some special tools to service cartridge forks, and the ones in this bike are NOT FUN to work on. If you have never done them before, I'd advise you to take to a dealer and pay them to do it.
 
You will need some special tools to service cartridge forks, and the ones in this bike are NOT FUN to work on. If you have never done them before, I'd advise you to take to a dealer and pay them to do it.
Click to expand...

I took my C14 in for service and asked the fork oil to be changed along with some other things.

The service writer thought I must have a leaky fork seal. I said no, the fork oil needs to be changed once in awhile. He had never heard of any one changing fork oil without a fork seal leaking.
 
Checked with the local Kawi dealer (Nault's in Windham NH) and they typically don't do C14 forks until the seal leak or if there is a noticeable deterioration in handling.  So I will probably go beyond 20K before considering servicing.
 
Kman,
I talked to the folks at Traction when I ordered my new suspension setup. They advise the oil be changed at the 15-20K mark for our sport tour kind of riding. Here is why; 
Our forks, (C14)  have a setup where the bushings are not exactly serviceable. Since they will wear faster with contaminated oil than with clean oil just makes sense to keep it clean right? You change you oil when it is dirty, (or before) to prolong your engine life right?
Matt
 
mattchewn said:
Kman,
I talked to the folks at Traction when I ordered my new suspension setup. They advise the oil be changed at the 15-20K mark for our sport tour kind of riding. Here is why; 
Our forks, (C14)  have a setup where the bushings are not exactly serviceable. Since they will wear faster with contaminated oil than with clean oil just makes sense to keep it clean right? You change you oil when it is dirty, (or before) to prolong your engine life right?
Matt
Click to expand...

It is true that the center bushing can't be removed from the fork upper half. You have to replace the upper half of the fork to replace the bushing in it. However, the lower bushing can be replaced. I'm a dealer for Traxxion and install their AK-20 kits in C14's, but I'll disagree with them on the service interval and say you can probably go 25K-30K, but I do agree it needs to be change regularly.

The difficult part in getting the forks apart on this bike is after you have the springs compressed, it takes a lot of force to get the cap up high enough to access the lock nut on the bottom of them. You'll need both a spring compressor and a lot of strength to pull up the cap, or a special tool like they show in the manual.
 
Fred, what's the dimensions of the replaceable bush please?  Not listed as a separate part, correct?  That's the lower one right, above the seals?

The centre one, is that in the centre of the outer tube, pressed in?  Or what/where exactly?

Thanks
 
Lower bushing can be removed. I haven't looked on the parts fiche to see if it is available or not. Yes, the upper bushing is in (approx)  the center of the upper fork half. I don't know how they get it in there, it doesn't appear to be split from what I can see of it. My guess is you just order the whole upper fork half when it wears out.
 
Just checked the fiche, and you're right, the lower bushing is not available by itself. Looks like you have to buy the whole upper half of the fork, which I assume comes with both bushings installed.
 
Kman said:
Checked with the local Kawi dealer (Nault's in Windham NH) and they typically don't do C14 forks until the seal leak or if there is a noticeable deterioration in handling.  So I will probably go beyond 20K before considering servicing.
Click to expand...

That is also my dealer so I am assuming you are in the area? I am in Londonderry
 
Reading about changing the fork oil, makes me think about others reading about doing a valve adjustment. Do I really need to do a valve check/adjustment?  My forks are fine, why should I go to the trouble, what is the risk, etc.?  BTW, I chacked my valves and adjusted 15 of them. The fork oil, not so sure?  ::)
 
With my low mileage 09 with 33K, I thought changing fork oil would be a good idea. Unfortunately the C14 is allot more difficult with out a drain plug at the bottom of the fork.  Plus every time I have seen used fork oil it always looked well used and abused.  I just felt it couldn't hurt.
 
Fred, thanks for the info.  Next time you have one apart, get the dimensions of the lower bush and I'll come up with a replacement for it - hopefully. 
 
I changed the oil in my R1 when it hit 20,000MI.

Anyone who does not think this is a good idea does not understand mechanics very well.

The bad part was, the R1 does not have a drain in the bottom like many bikes do, so I had to take the forks off, unscrew the cap and dump it out, put them back on.

I thought I Saw a drain on the C14 last time I Was under there scraping bugs. IF there is, I'll change it at 10,000
 
JTX,
There is no drain on the C14 forks. I will be installing one on my new ZX14 forks I am installing though! Life should be simple!
Matt
 
mattchewn said:
JTX,
There is no drain on the C14 forks. I will be installing one on my new ZX14 forks I am installing though! Life should be simple!
Matt
Click to expand...

Well that answers that question then =D
 
mattchewn said:
JTX,
There is no drain on the C14 forks. I will be installing one on my new ZX14 forks I am installing though! Life should be simple!
Matt
Click to expand...

Would like to follow this when you get it done, Matt.
Gary
 
It seems the first fork oil change is important as I've seen more contamination in stock oil forks. It may be lower quality OEM fork oil or/and the parts wearing into each other a bit but it's always been cleaner after the first change. I was going to mention flushing them out the first time gets allot of additional crud out of the bottom of the legs. I just changed my Bandit fork oil and installed gold valves and used contact cleaner to flush them out the the bottom cartridge mounting hole. Lots more swarf hiding there.
I used various brands of oil and worked with a guy who was a top tier flat track/ice racer. I asked what brand he used since he rebuilt and tuned more forks than I ever dreamed of. He said he also tried many brands and now only uses Silcolene. I inquired "because it dampened the best"? He said not really, it always came out cleaner than the other brands hence less wear. Works for me.
 
Tundra Tom said:
It seems the first fork oil change is important as I've seen more contamination in stock oil forks. It may be lower quality OEM fork oil or/and the parts wearing into each other a bit but it's always been cleaner after the first change. I was going to mention flushing them out the first time gets allot of additional crud out of the bottom of the legs. I just changed my Bandit fork oil and installed gold valves and used contact cleaner to flush them out the the bottom cartridge mounting hole. Lots more swarf hiding there.
I used various brands of oil and worked with a guy who was a top tier flat track/ice racer. I asked what brand he used since he rebuilt and tuned more forks than I ever dreamed of. He said he also tried many brands and now only uses Silcolene. I inquired "because it dampened the best"? He said not really, it always came out cleaner than the other brands hence less wear. Works for me.
Click to expand...


I used silcolene as well.  Still have some from that project.
 
When changing the fork oil, how is everyone cleaning the old oil and residue out of the forks? It seems to me, to have an effective oil change, that the fork tube/legs should be clean before adding new oil. On my other bikes, I have done this before. But I completely disassembled the forks as I was changing the seals. So I was able to clean the tubes out with Simple Green. However on my C14, I was not going to change the seals, only looking to do an oil change. Thoughts please.
 
Sailor_chic said:
When changing the fork oil, how is everyone cleaning the old oil and residue out of the forks? It seems to me, to have an effective oil change, that the fork tube/legs should be clean before adding new oil. On my other bikes, I have done this before. But I completely disassembled the forks as I was changing the seals. So I was able to clean the tubes out with Simple Green. However on my C14, I was not going to change the seals, only looking to do an oil change. Thoughts please.
Click to expand...

Personally, if the fluid is not dirty, and full of particles I wouldn't do anything but dump new fluid in it.

But if you decide to feel the need to clean it, just use some cheap fluid swish it around and dump it out.  I would never put anything in my fork tubes that is not fork oil fluid since you'll never get it all back out.

Since you have it apart already, you already have to ( in most cases ) pull the fork seals, so NOT replacing them is not an option to me personally.  You will likely cause damage to the ones that are on there during removal. They will surely leak after.  They arent expensive. Just replace them.

 
Sailor_chic said:
When changing the fork oil, how is everyone cleaning the old oil and residue out of the forks? It seems to me, to have an effective oil change, that the fork tube/legs should be clean before adding new oil. On my other bikes, I have done this before. But I completely disassembled the forks as I was changing the seals. So I was able to clean the tubes out with Simple Green. However on my C14, I was not going to change the seals, only looking to do an oil change. Thoughts please.
Click to expand...

As JTX mentioned if you are just changing the fluid I would just flush them with fork oil.
Most of the wear crud settles to the bottom. The only way to get it all out is removing the cartridge in the bottom of the fork leg. I then blast it out the bottom bolt hole with contact cleaner as it leaves little or no residue. I did have a thought about using a tube with compressed air lowered to the bottom with some oil left in it to stir things up before dumping. You may want to turn your face away from the top when attempting this. :)
 
I am a fan of ride it till it breaks and then fix it right.  If you are going to go through the hoops to change the oil you should rebuild it all.  I didn't once, seals failed soon after.
 
I concur.... if ur gonna change the oil, replace the seals cuz within 5 months they're gonna start leaking..... murphy says so....
 
PG :  Make sure you use a 6-point 10mm socket to remove the lower pinch bolts.  Those bolts are soft and can be stripped easily with a 12-point socket.  Don't ask me how I know.
 
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