WP4860 Fork Service For Dummies

[Ji Gantor]

With the tubes seperate take note of how all the parts go back on.

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Ji

[Ji Gantor]

Also check to see if there are any problems, scratches or worn out parts.
When removed they need to be cleaned ready for reassembly.

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Ji
 

[Ji Gantor]

Now that all the parts are clean we are ready to reassemble.
So we don't scratch the new seals on the sharp edges of the inner tube, wrap a few layers of sticky tape over all the sharp edges.
WP do have a tool for this so if sticky tape is not for you please ask Walter where you can get one.

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Ji

[Ji Gantor]

smear some fork oil over the sticky tape and gently slide the mud wiper circlip and new oil seal over the end of the inner tube. After oil seal is on remove sticky tape completely.

I have read the manual for this fork, and today asked my local KTM Team Moto mechanic what level should the oil be.
The manual states 100mm down from the top, the KTM fellow told me 140mm down from the top.

I tried 140mm down from the top but as I slid the cartridge up and down to remove trapped air I could hear cavitation, so I gave 100mm a try and no more cavitation. This is not a recommondation just logic.
Please use specified amount.

Reassemble forks in reverse to strip down.
Make sure you turn your compression and rebound clickers counterclockwise before you reassemble.
After assembly set compression and rebound back to their original positions.

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Ji

[Ji Gantor]

Hey Jock if you have any questions or need some advice please let me know.
These forks are pretty easy to service.
It took me about an hour to strip, clean and reassemble one fork.

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Ji

[TT5 Matt]

i just used the plastic bag the seal came in as a protector

[LWC82PE]

Part number for the seal tool is T1401

[Ji Gantor]

I am sure there are heaps of ways to skin that cat Matt.

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Ji

[Ji Gantor]

Hi LWC,
Yes my manual states all the tool numbers but where can you buy them?
most of these special tools I have found can not be purchased.
Not even the bike shops use them when servicing your bike because again they don't have them either.

The split seal driver is needed to install the seal back into its seat.
The oil level tool makes things easy but not required. You can just use a stick.
WP have inner and outer tube vise tools and all sorts.
Walter probably has a few for sale if any one is interested.


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Ji

[LWC82PE]

JI they are available, just try any KTM dealer. I made some tools my self but i like the genuine WP tools because a lot are made in Germany and good quality.

[evo550]

Ji,
What year ktm are the forks from?

[Ji Gantor]

Hi Evo,
The forks are off a 2003 KTM.
I thought that the Pre 90 forks could be similar but as Holeshot said they are not.
I have serviced RM125 1994 forks and they are pretty similar.
Oh well I hope it helped someone.

Tight nuts

Ji

[Ji Gantor]

Hi LWC,
I will ask my local KTM dealer and see what they say.
The original tools are always the best to use.
Thanks mate.

Tight nuts

Ji

[Ji Gantor]

Check the oil that came out of your fork.
The oil will be discoloured, that is normal even after only one ride.
Check the volume.
I caught 450ml in the container and lost on the vise about 100ml and the drip tray has about 50ml so roughly 600ml came out.
I don't let a weeping seal go because I have seen what that does. The outer tube can become worn on the inside to the point were it clunks and has to be replaced. The amount of new oil poured into the fork was about 600ml.
Don't over fill the fork with oil or it will go hydraulic. That is oil can not be compressed but a gas like air can. If you fill your fork to much you will not be able to compress it, try that over a jump. Also I have seen one pair that has an internal buldge, I am not sure why but it may be from over filling, but that said I would expect the seals to just blow.

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Ji

[Ji Gantor]

If you have not seen one of these great tools it is a fork seal installer.
It fits over the inner tube and slide hammers the seal into place.

They cost about $70.00 and can be purchased in all fork sizes, this one is 47 - 48mm.

Tight nuts

Ji