I swore there was another article on here or somewhere that details this exact procedure... but having searched fruitlessly I decided to write another and post it in case someone else would like to do the exact same.
Additional useful thread Hyperpro-front-fork-springs-which-way-round-and-other-stuff
Tools needed:
T35, T40, E12, Hammer, punch.
10 Weight fork oil 1.5 litre Haynes manual states 530ml per leg.....
The main issue for me was front end dive on braking which was beginning to bug me, the other reason was that I was beginning to get more adventurous off road, having bottoming out the forks a few times, so I decided to try and upgrade a little.
OK shall we start:
The Haynes manual details taking off all body work at the front to avoid scratching it up. I didn't bother as A) I'm not overly precious of my bike. (It’s a working bike), and B) I'm lazy
Tip 1: Loosen up all bolts while forks are still in the clamps and wheel is still attached.
Jack up under the sump to support the front end and raise the wheel off the ground.
Undo the speed sensor so it’s out of the way undamaged before you get the wheel out. Remove wheel remembering to push the caliper in
from the outside to increase the gap inside where the brake pads are. (Makes it easier to put the front wheel back in later).
Remove caliper and place it supported either with string out the way or hook it conveniently on the sump guard.
Remove mud guard
Undo the 4 bolts on the fork bridge to remove.
Undo top and bottom fork clamp bolts.
Picture of top of the forks with plastic cap taken off. Note the corrosion :-(
Slide the leg out remembering to smash the damn thing into the ground as you didn't raise the front end up high enough!...
Pop the top cap on the fork and inspect the top plug. (The plug maybe corroded, if it is spray some anti-seize in.)
The plug is held in place by a circlip and the pressure from the internal fork spring. You can push the actual plug down with your
thumb. If it’s corroded, use punch and give it a few taps until it moves freely up and down.
Depress the plug and remove the circlip. The plug should come out if you slightly compress the fork legs and basically pop it off. (The spacer forces it out). Inspect the plug seal to make sure its not perished. (Replace if necessary)
Remove spacer and depress the fork to get to the spring.
Pour oil out into something. Pump the forks several times to help drain the remaining in the bottom. GIve the inner a clean with wire wool if it needs it, be careful not to get any wool fragments drop into the internal fork.
Refill forks until level of oil is about 100mm [Edit: should be 190mm] from the top of the inner leg when the fork is fully depressed. Pump the forks a few times to allow the new oil to work its way in. Insert new spring and
spacer back in.
Comparison between both spring types, spacer present also.
Reinsert plug and fasten down with circlip.
Chuck a little fork oil in the top and swill it around to help keep the plug from corroding.
Other fork is exactly the same.
Reverse procedure to reassemble. While you are at it, cover everything in ACF 50.
I took the opportunity to install some fork boot protection.
Remember to pump the brake a few times before you test the work you've done.
Have a cup of tea and admire your work.
Additional useful thread Hyperpro-front-fork-springs-which-way-round-and-other-stuff
Tools needed:
T35, T40, E12, Hammer, punch.
10 Weight fork oil 1.5 litre Haynes manual states 530ml per leg.....
The main issue for me was front end dive on braking which was beginning to bug me, the other reason was that I was beginning to get more adventurous off road, having bottoming out the forks a few times, so I decided to try and upgrade a little.
OK shall we start:
The Haynes manual details taking off all body work at the front to avoid scratching it up. I didn't bother as A) I'm not overly precious of my bike. (It’s a working bike), and B) I'm lazy
Tip 1: Loosen up all bolts while forks are still in the clamps and wheel is still attached.
Jack up under the sump to support the front end and raise the wheel off the ground.
Undo the speed sensor so it’s out of the way undamaged before you get the wheel out. Remove wheel remembering to push the caliper in
from the outside to increase the gap inside where the brake pads are. (Makes it easier to put the front wheel back in later).
Remove caliper and place it supported either with string out the way or hook it conveniently on the sump guard.
Remove mud guard
Undo the 4 bolts on the fork bridge to remove.
Undo top and bottom fork clamp bolts.
Picture of top of the forks with plastic cap taken off. Note the corrosion :-(
Slide the leg out remembering to smash the damn thing into the ground as you didn't raise the front end up high enough!...
Pop the top cap on the fork and inspect the top plug. (The plug maybe corroded, if it is spray some anti-seize in.)
The plug is held in place by a circlip and the pressure from the internal fork spring. You can push the actual plug down with your
thumb. If it’s corroded, use punch and give it a few taps until it moves freely up and down.
Depress the plug and remove the circlip. The plug should come out if you slightly compress the fork legs and basically pop it off. (The spacer forces it out). Inspect the plug seal to make sure its not perished. (Replace if necessary)
Remove spacer and depress the fork to get to the spring.
Pour oil out into something. Pump the forks several times to help drain the remaining in the bottom. GIve the inner a clean with wire wool if it needs it, be careful not to get any wool fragments drop into the internal fork.
Refill forks until level of oil is about 100mm [Edit: should be 190mm] from the top of the inner leg when the fork is fully depressed. Pump the forks a few times to allow the new oil to work its way in. Insert new spring and
spacer back in.
Comparison between both spring types, spacer present also.
Reinsert plug and fasten down with circlip.
Chuck a little fork oil in the top and swill it around to help keep the plug from corroding.
Other fork is exactly the same.
Reverse procedure to reassemble. While you are at it, cover everything in ACF 50.
I took the opportunity to install some fork boot protection.
Remember to pump the brake a few times before you test the work you've done.
Have a cup of tea and admire your work.
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