Front fork question

[Mikey]

Has anyone removed the front forks to replace the fluid? Does anyone know how to remove the spring seat? I assume that is the cap. On the ST1100 the cap was held on by fine threads. Looks like the forks themselves are easily removed from the bike.

[robber57]

Did it one week ago,
Take the wheel out and put a dummy axle in, take the 4 bolts out and each leg, this may need some hammering with a soft plastic hammer on the dummy axle,on top is a plastic cap, just pry it out.
Then push inwards the steel top cap, you will see a fine wire circular clip inside a groove in the frontfork, remove with a fine screwdriver, give the frontfork a tap and the steel cap will come out due to the spring.
The 6 mm allen key bolt at the bottom can be horrifically stubborn and the bolt is just a mild steel bolt so the allen recess is easy to damage, use a high quality spanking brand new allen key and push on it to make sure it will not come out of the bolt and damage the allen recess.
Give it one good jerk and it will make that "KNACK" sound and come loose, if youre to cautious you will slowly kill the allen bolt.

DONT put loctite on the bolt when you put it back like the service manual suggest, the next time you want to take it apart you will have a hell of time to get the bolt out as the internals of the fork will rotate due to the loctite.
Just using a new 8 mm copper washer should be sufficient to keep it from coming loose, dont use the old copper washer.

Use a syringe or such to accurately measure the 100 cc of oil for each leg, over or under filling a few cc will cause the fork to have a much softer or harder spring action, the trapped air in the fork will be compressed when push in the fork--> more oil is less trapped air so it will become stiffer, also overfilling a lot will cause the seal to explode/break.

The outer seal can be pried out with (only)your finger to be thoroughly cleaned, leave the inner seal where it is.
clean inner and outer tubes thoroughly in a mild solvent, remember: a front fork is a closed hydraulic circuit, every grain of sand/dirt you leave inside will stay there forever and do its grinding and damaging work on those very nice shinny and perfect surfaces, it just takes one grain of sand to ruin it.
"thoroughly" means that you will have to brush/wipe every bit of the inside of both tubes and rinse to the point that your solvent will stay clear, a piece of cloth on a broomstick soaked in solvent will do this.
Be careful with the solvent, dont leave the rubbers overnight in it and make sure to use something that wont eat the rubber of the seals, i always use white spirit or what you may call "coleman fuel" or "zippo lighter fuel" because it evaporates 100%,doesnt leave any residue and is mild to rubber seals.
Alternatively you can wash the parts in just warm water and soap, off course this means that afterwards you will have to dry the parts 100% with compressed air or a heat source like a hairdryer.

Put just a tiny bit of grease in the seals when you assemble everything,grease catches sand and dirt and thats not what you want.
Observe the correct mounting of the spring ,the close wound end goes in first.

[TommyXP]

Question: Is a hydraulic press (as stipulated in manual) or other special tools necessary to accomplish the task? Can it be "man-handled"?
Have never done this but will be in the future.....

[robber57]

No, i saw it in the manual, thats ridiculous/over the top

The steel top cap can be pushed easily in with a screwdriver and your hand, you may need a second person to push the cap while you take out the circlip.
You need wrench 12-14-19 mm and allen key 6 mm+ some sort of wrench/pipe to put on the short arm of the allen key as it will be to short and you will need to use the long arm, a small fine point screwdriver and maybe a plastic hammer

[Arbiter]

robber, thanks for description. Have you ever tried to change springs to softer?

[robber57]

No, i weigh a whopping 110 kgs so if i would do anything to the front suspension it would be adding a bush to make it a bit stiffer, it is already for a while on my to-do list but i just cant find any time for it.

[Arbiter]

How long are springs in front fork?

I have another bike - honda CBR250r and this one has perfecly soft front suspension. I dont like SH125 suspension - very hard and small travel

[robber57]

257 mm

[Arbiter]

thank you very much Robber. So they are short and the travel is ugly . And do yopu know dia this spring ?

[robber57]

There are alternative springs for the sh , search the forum and you will find some (2?) brands.