Stock KDX200/220 Shim Stack Mod
Posted: 03:43 pm Jul 27 2013
Stock KDX 200/220 Free Fork Shim Stack Mod
Tools Needed:
14mm hex w/ 1/2 driveor proper adapter
1/2 drive impact gun
12mm or 10mm wrench
1. Raise and support the front end of the bike
2. Remove the Front caliper
3. Remove the front wheel
4. Un-clamp the brake line from the left fork and position aside
5. Loosen the triple clamp for one fork then remove that fork
6. Repeat step 5 for remaining fork
7. There is no need to drain the fork oil unless you want to change it
8. Pick a fork to be specimen number 1
9. Turn it upside down and compress it
10. Remove the rubber plug that protects the compression clicker
11. Using your impact driver and 14mm hex, loosen the valve assembly from the bottom of the fork ****Note that you should release the compression of the fork once the valve is loose enough to remove by hand****
12. On top of the valve assembly there is a nut you will need to remove it. ***Note that the thread on the shaft is staked at the top, so the nut will be hard to remove. Once it is off, clean up the top of shaft thread with a file, to make it easier to remove the rest of the components****
13. Under the nut is a plate and spring. The plate has 'fingers' that curve down and hold a series of thin washers, these are the SHIMS. ***note direction for reassembly***
14. There will be 10 shims - take two of them out. Put the rest back onto the stack (inside the 'fingers') and place the whole assembly back onto the shaft. ***Note don’t assume there’s 10 there somebody may have done this mod already so count them***
15. Apply some locktite (or equivalent thread locker) to the threads this is important as you have filed off the locking tabs
16. Replace the nut and tighten it up 25 in/lbs (Too tight and you will strip the thread turning a free mod into a stupid repair).
17. Make sure the valve is clean free of any metal filings from step 12 before placing it back into the bottom of the fork. Compress the fork once more and start the valve by hand 2-3 turns before using the impact driver to tighten the valve in the bottom of the fork
18. Set the fork aside and grab number 2 and repeat steps 9-17
19. Once completed do steps 1-6 backwards and obviously change loosen to tighten, raise to lower, un-clamp to clamp and remove to install I shouldn't have to say that.
This mod really is free and noticeably improves the action of the fork on hard, square edged bumps such as rocks and roots. This is because the shims absorb the initial impact (the high speed circuit) by restricting oil flow before the fork springs start to take the shock (the slow speed circuit). The rocks and roots don't make the forks move deeply enough for the springs to take up enough of the impact. By removing two shims you are reducing the resistance to the oil flow and therefore making that initial stroke plusher - just enough to make the front end a lot less jittery over the sharp stuff. If you think it is a little too soft now, simply replace one shim. Gold valves have a more advanced shim stack and can be tuned a lot more precisely than the stock valve. They also cost $$$ whereas this mod is totally free unless you value your’ labor.
Tools Needed:
14mm hex w/ 1/2 driveor proper adapter
1/2 drive impact gun
12mm or 10mm wrench
1. Raise and support the front end of the bike
2. Remove the Front caliper
3. Remove the front wheel
4. Un-clamp the brake line from the left fork and position aside
5. Loosen the triple clamp for one fork then remove that fork
6. Repeat step 5 for remaining fork
7. There is no need to drain the fork oil unless you want to change it
8. Pick a fork to be specimen number 1
9. Turn it upside down and compress it
10. Remove the rubber plug that protects the compression clicker
11. Using your impact driver and 14mm hex, loosen the valve assembly from the bottom of the fork ****Note that you should release the compression of the fork once the valve is loose enough to remove by hand****
12. On top of the valve assembly there is a nut you will need to remove it. ***Note that the thread on the shaft is staked at the top, so the nut will be hard to remove. Once it is off, clean up the top of shaft thread with a file, to make it easier to remove the rest of the components****
13. Under the nut is a plate and spring. The plate has 'fingers' that curve down and hold a series of thin washers, these are the SHIMS. ***note direction for reassembly***
14. There will be 10 shims - take two of them out. Put the rest back onto the stack (inside the 'fingers') and place the whole assembly back onto the shaft. ***Note don’t assume there’s 10 there somebody may have done this mod already so count them***
15. Apply some locktite (or equivalent thread locker) to the threads this is important as you have filed off the locking tabs
16. Replace the nut and tighten it up 25 in/lbs (Too tight and you will strip the thread turning a free mod into a stupid repair).
17. Make sure the valve is clean free of any metal filings from step 12 before placing it back into the bottom of the fork. Compress the fork once more and start the valve by hand 2-3 turns before using the impact driver to tighten the valve in the bottom of the fork
18. Set the fork aside and grab number 2 and repeat steps 9-17
19. Once completed do steps 1-6 backwards and obviously change loosen to tighten, raise to lower, un-clamp to clamp and remove to install I shouldn't have to say that.
This mod really is free and noticeably improves the action of the fork on hard, square edged bumps such as rocks and roots. This is because the shims absorb the initial impact (the high speed circuit) by restricting oil flow before the fork springs start to take the shock (the slow speed circuit). The rocks and roots don't make the forks move deeply enough for the springs to take up enough of the impact. By removing two shims you are reducing the resistance to the oil flow and therefore making that initial stroke plusher - just enough to make the front end a lot less jittery over the sharp stuff. If you think it is a little too soft now, simply replace one shim. Gold valves have a more advanced shim stack and can be tuned a lot more precisely than the stock valve. They also cost $$$ whereas this mod is totally free unless you value your’ labor.