Fork oil replacement question

Ive got some new springs coming and want to change the fork oil at the same time. Can I just undo the damper rod at the bottom to drain the old oil then refill the forks?



Just thought it would save dropping the legs off the bike.

You should strip them down and fluch them. Draining will not get all the old oil out. Are you installing gold valve at the same time ? Well worth the extra few bucks.

Hammy wrote:You should strip them down and fluch them. Draining will not get all the old oil out. Are you installing gold valve at the same time ? Well worth the extra few bucks.

Couldn't afford the gold valves, will see how it is with stronger springs. Should I go for 10w oil?

NZspokes wrote:

Hammy wrote:You should strip them down and fluch them. Draining will not get all the old oil out. Are you installing gold valve at the same time ? Well worth the extra few bucks.

Couldn't afford the gold valves, will see how it is with stronger springs. Should I go for 10w oil?

When I had my forks done they replaced the oil with 5W. That was with new valves. 10W will be fine.

Thread steal.
Hi All just need advice please . . . I have a 2002 1200S. I am doing my first oil change on it and cannot locate the bottom drain hole in the forks. Does that mean I will have to remove front wheel, brake line etc and forks from headset to enable me to drain old oil from forks or is the drain in a secret location somewhere?
I am putting in 10W and 509 mil per fork as this is what was on the print out sheet from our local Suzuki Dealer here in the Ville.

Thanks In Advance.

I don't think there is a drain hole in any forks I've seen.

Apparently some forks do have bleeders at the bottom, I think some beemers have this. The bandit is a forks out job, once you get them out you'll see the bolt at the bottom once you get the wheel and axle out of the way.

Why are we undoing the bottom bolt again ?  Its not a fork seal job .
Remove fork ,undo cap , remove spring , turn fork upside down  ,oil will run towards earth , No ? 

gus wrote:Why are we undoing the bottom bolt again ?  Its not a fork seal job .
Remove fork ,undo cap , remove spring , turn fork upside down  ,oil will run towards earth , No ? 

4 easy steps Gus   

Had an old XR or KLR that had drain holes at bottom of forks for this purpose so I thought it was a common thing to make it easier for us. How wrong can a bloke be?
so just to clarify I need to remove fork first >cap>spring>turn fork upside down>drain oil.
I might remove the cap while it is still clamped as it may be easier to do it this way.

Thanks all for the advice. Will hit it tomorrow and see how I go. This is the first fork oil change in a lot of klm.

I believe you'll have to pump the fork to get all the oil out

Thanks reddog.

And pump it a fair amount also when you refill to bleed the air out.

The forks caps are aluminium with a very fine thread that is easily damaged. Back your preload down to minimum before removing them. Backing off preload reduces the pressure on the thread. If you don't have a vice with soft jaws to clamp the slider, then half remove the fork caps while they are still clamped in your triples, then remove forks.
Removing the fork cap from the damper rod is the same. The fork cap has two flat milled surfaces to lock it to the damper rod lock nut. Take your time to make sure you don't damage it , its very soft.

After you remove the retainers remove the springs and invert the fork to drain it then pump the damper rod to cycle the oil out of the damper cartridge. If you don't pump it out the old oil will remain in the cartridge. Same on filling - cycle the damper  rod to refill the cartridge.
Do you have gear to set the oil height?

Sheesh! OK there is a drain at the bottom of the forks that is accessible after the axle bolt is removed. One of mine was stripped so I had to take forks off bike to allow me to invert the forks and drain the oil.

!Tag - Not really a mechanical person so sorry for my naivity but what gear do I need to set the oil height? I thought it was a matter of removing old oil, pumping the forks and simply pouring in the required amount into each fork?

Thanks all for the advice thus far.  

The bolt in the bottom of the fork is not a drain hole, its the bolt that anchors the damper cartridge into the fork leg. If its stripped your in trouble.
It will then become a drain plug (after its installed). You'll notice that these two bolts (allen head screws) have copper crush washers to seal them. If you get oil leakage after reassembly you'll have to seal them somehow (thread sealant or helicoils if they're really stuffed)

I'm guessing you have a manual available to get the recommended oil volume. If so it shows how to set your oil height. The recommended oil volume will give you the right oil height if the forks are completely dry. The oil height is the important measurement though. If you don't completely drain the fork, when you add the recommended amount of oil the oil height inside the fork is higher than normal and you get what is known as "air spring". It makes the fork stiffen in the lower end of its stroke. If you've left a lot of oil in the fork it can blow the seals out or hydraulic the dampers in the worst case.

Changing oil height and viscosity are the two ways you change the action of a non adjustable fork.

Fork oil height kits are sold online and in stores but I use a very cheap set. They basically are a syringe and you overfill the fork then withdraw oil until it gets down to the height you're after. If you go to a chemist he'll sell you a gastric lavage syringe (you'd know it better as a stomach pump  ) for two or three bucks and the end of these accept 6mm id plastic tube (hardware store). Put a length of tube on the end of the syringe and cut it to the recommended length and sit the shoulder of the syringe on the top of the slider and suck till nothing more comes out and your oil is at the right height. (or don't bother but make sure you've thoroughly drained the fork and just add the recommended amount). If you do it this way note the fork is filled without the spring installed and the slider bottomed in the fork leg.

Thanks !Tag for the thorough "how to" instructions and for the explain on the drain hole I thought I had found.   
Will have a go at it when I get home.

truck