Another KYB SSS Thread - 2013 EC250R
- Thread starter Jakobi
- Start date
twowheels
New member
Mr Beane took on the role of parts acquisition and spacer manufacture! Took a while to get things sorted, but they are in the mail now so I guess its time to pull the valving out and get busy!
Rather than spin the spacers out of stainless I used 6061 and then had a hard-coating process performed on them. The spacers fit up to both the stock GasGas wheel and the Yamaha axle shown in the picture.
Next up is work on stripping and hard-coating Marzocchi upper fork tubes ...
Jakobi
Super Moderator
Starting to get giddy now! Parts should be here by end of the week, or next at the latest. Thought I better pull a finger and spend some time in the shed.
Those KYBs certainly haven't been used since new. No tooling marks visible. Oil was like new, and I almost considered saving it and reusing it in the outers, but it did have a few flecks through it from manufacture so I'll play it safe with fresh oil throughout. Whats a few more dollars in fluid. Seals still have quite a bit of stiction. I'll pop the dust wipers down and use some of my slickoleum between the seals and wipers to help get things moving smoothly. Happy enough to stick with the stock KYB seals at the moment.
Everything has been pulled down. Peening removed from the valve posts. Stacks and pistons pulled, cleaned, and ready for adjustment. Let me know if you want the stacks posted, or else I'll keep it secret squirrel.
Tomorrow need to throw the new shim stacks on, confirm the float physically, and drill the ICS pistons. I'll also remove the upper o-ring for less stiction. Should have no worries getting them bled up and back together, and with any luck the rest will arrive at the post office and I'll be able to bolt it up and give it a test ride the next day.
Those KYBs certainly haven't been used since new. No tooling marks visible. Oil was like new, and I almost considered saving it and reusing it in the outers, but it did have a few flecks through it from manufacture so I'll play it safe with fresh oil throughout. Whats a few more dollars in fluid. Seals still have quite a bit of stiction. I'll pop the dust wipers down and use some of my slickoleum between the seals and wipers to help get things moving smoothly. Happy enough to stick with the stock KYB seals at the moment.
Everything has been pulled down. Peening removed from the valve posts. Stacks and pistons pulled, cleaned, and ready for adjustment. Let me know if you want the stacks posted, or else I'll keep it secret squirrel.
Tomorrow need to throw the new shim stacks on, confirm the float physically, and drill the ICS pistons. I'll also remove the upper o-ring for less stiction. Should have no worries getting them bled up and back together, and with any luck the rest will arrive at the post office and I'll be able to bolt it up and give it a test ride the next day.
(F5)
Gold Level Site Supporter
Sounds like things are moving well. So are you using WR specs to compare valving with ?. I've heard there's a plastic spacer thingy part that breaks sometimes and racetech makes replacement ones but had run out for a bit. An internet mate showed up in my garage last weekend, turns out he makes them for a local shop who then gets them anodised and sells quite a few about nz
Jakobi
Super Moderator
The plastic part is the ICS piston. If the seal fails it allows oil to accumulate on the other side of the piston which can result in the pressures beyond what the plastic can handle. The after market ones are not sealed and vent so the problem doesn't occur. I'll be drilling 4 x 3mm holes in my plastic ones from the get go.
Valve stack is one I've come up with myself. Essentially I've kept most of it the same as the YZ250F, with exception of adding a 26mm crossover, and dropping total face shims from 24 down to 15. No bleed stack.
Valve stack is one I've come up with myself. Essentially I've kept most of it the same as the YZ250F, with exception of adding a 26mm crossover, and dropping total face shims from 24 down to 15. No bleed stack.
Jakobi
Super Moderator
With no holes drilled, you essentially have a 3 chamber fork. The area in the outers (air and oil air gap set by volume), an area above the ICS piston (all air), and the area below (all oil).
By drilling the piston, you are basically extending the the upper section to be included with the volume of the outers. It likely does have some effect is softening the resistance the ICS piston faces under compression, but then a lot of people go to lighter ICS springs as well.
The after market pistons will do the same thing, and quite a few forks are designed this way to begin with, so while it does change things, I don't believe it is for the worse. On the contrary, having a piston explode due to a leaking seal isn't an ideal scenario.. One I'd rather avoid.
By drilling the piston, you are basically extending the the upper section to be included with the volume of the outers. It likely does have some effect is softening the resistance the ICS piston faces under compression, but then a lot of people go to lighter ICS springs as well.
The after market pistons will do the same thing, and quite a few forks are designed this way to begin with, so while it does change things, I don't believe it is for the worse. On the contrary, having a piston explode due to a leaking seal isn't an ideal scenario.. One I'd rather avoid.
Jakobi
Super Moderator
Keeping them for spares/sale of the bike. They're still ridable, just not up to the standard I've come to expect. I'd still use them myself, however I feel them degrade after a couple of rides, and its not feasable for me to change oil that frequently.
What happened to yours?
Diggs345
Gold Level Site Supporter
Nothing yet , I'm picking up a new husky fe350 and heard the marzocchi carts in the 4cs forks were the dogs danglies.
Jakobi
Super Moderator
I assure you my carts won't be dogs dangles. One of them at least! I thought the tuners had finally got their heads around the 4CS fun.
Diggs345
Gold Level Site Supporter
They have stateside by the looks of it , not sure about the uk though , ziptie do an adapter to put the marz carts in too
Jakobi
Super Moderator
Dave from Suspension Matters has been working with Adam from Kreft I believe, and have some good things sorted. Don't know where you'd stand $$ for what they do. I wonder if they'd sell their kit on for home install.
Back on topic. Been bloody lazy and just tinkering here and there getting little dribs and drabs done. Parts didn't arrive so motivation to finish up quickly has passed.
All valve stacks sorted out, back on the stems. Pistons modified. About to go and bleed the carts and probably call it done for the day.
Back on topic. Been bloody lazy and just tinkering here and there getting little dribs and drabs done. Parts didn't arrive so motivation to finish up quickly has passed.
All valve stacks sorted out, back on the stems. Pistons modified. About to go and bleed the carts and probably call it done for the day.
Jakobi
Super Moderator
Few pics for anyone who's interested.
Mid valve shim assortment
Everything ready to go back on the posts
ICS pistons modified, cleaned up and put back in place. Valve posts installed, and base valve comp stack in place.
Base valve piston, check plate, cup washer, and nut back on and torqued to spec with blue loctite.
And same treatment for the midvalve.
Mid valve shim assortment
Everything ready to go back on the posts
ICS pistons modified, cleaned up and put back in place. Valve posts installed, and base valve comp stack in place.
Base valve piston, check plate, cup washer, and nut back on and torqued to spec with blue loctite.
And same treatment for the midvalve.
Jakobi
Super Moderator
I still need to measure the preload on the main spring and determine if I want to modify the spring perch to reduce it. At this stage if its under 5mm I will probably leave it to begin with.
The stock springs are 4.5N (.46kg/mm) which may be on the firm side for my application. In my Zokes I was using .44kg/mm and in my TTX which I have been running I am using .46kg/mm. It will likely be acceptable, but maybe not super soft. I may look to source a .42kg/mm to use in one side if it is too firm.
ICS spring is a heavier one at 22N. I'll have to see how this works. I'd probably have prefered a 20N spring which came in some of the other models of SSS.
Stock mid valve float was .35mm. I removed a face shim (.11/.12mm KYB shim) and added a .2mm backer to close the float again. Puts me around .26-.27mm.
On the base valve, I removed a handfull of shims and put a 26mm crossover in. It should be much softer than stock. Overall I expect the fork to still feel quite firm and sharp, but be very compliant without feeling mushy.
The stock springs are 4.5N (.46kg/mm) which may be on the firm side for my application. In my Zokes I was using .44kg/mm and in my TTX which I have been running I am using .46kg/mm. It will likely be acceptable, but maybe not super soft. I may look to source a .42kg/mm to use in one side if it is too firm.
ICS spring is a heavier one at 22N. I'll have to see how this works. I'd probably have prefered a 20N spring which came in some of the other models of SSS.
Stock mid valve float was .35mm. I removed a face shim (.11/.12mm KYB shim) and added a .2mm backer to close the float again. Puts me around .26-.27mm.
On the base valve, I removed a handfull of shims and put a 26mm crossover in. It should be much softer than stock. Overall I expect the fork to still feel quite firm and sharp, but be very compliant without feeling mushy.
