Got a request to revisit this one, so here goes: Here's one I picked up from the race team. Fork: Don't go by the lines on the slider or the protrusion above the top clamp thinking the legs are square at the axle. After a service or front wheel removal- you wan't to make sure the axle slides in w/o resistance. Install the right leg, snug it up so it wont move- top clamp bolt first. Then try and slide in the (straight BTW) axle and see if it goes in the left carrier bore. If it's off-set (see pic, this is with equal protrusion above the top clamp, it's off by almost 3mm!) the fork will bind or want to "yaw" the wheel on the vertical axis. Adjust the left leg up or down. Then, once you have the axle slipping in and out of it's bores freely, lightly snug a bolt or two on the axle clamps. Now, grab your inch-pound wrench and convert the spec in the manual to same. Torque the top right, then lower right, then lower left, then upper left fork clamp bolts. Now you can install the front wheel with out a hammer and the fork will be as sticiton free as possible. . And why then do these forks have little lines on the top of them if they are not "accurate"? Simple- they are close, but, they are used to speed up-production on the factory floor. Your fork may be perfectly square, but probably not if it isn't blueprinted. So don't trust the lines!
in the world of one leg does spring and one leg does damping the legs are fighting against each other on every movement anyway
good point. are those even being made anymore? i remember that type vaguely. cant recall the last time ive seen one...i forgot all about those til you mentioned it! lol. but the type of fork featured here? every little bit helps.
Showa uses the SFF on MANY of the top MX bikes right now. Many recent years of KX250Fs, RMZ 250 and 450, etc. I believe that the new generation of air forks (Showa TAC and maybe the KYB PSF) is also damping in one side, and those come on many of the top tier bikes (CRF450, mabye CRF250, RMZ, KXF). So yeah, they're still being made. Aligning the forks as described above is a good idea to make installation of the axle easier, but it doesn't make any difference in stiction. If forks were sensitive to a few mm of spring preload difference, the SFF/TAC model would be a complete disaster, but it works fine.
yeah i thought sff (single function fork eg each leg does a seperate function springing vs damping) was pretty wide spread in the current crop . if ur axle is a pig to fit then do this regardless
I've got a buddy with a KTM200 and his forks have never been right, in the fact they don't return correctly. This is great info! - Thanks.
The 4CS are single function forks as far as I understand it anyway. Left does compression and right does rebound(might be opposite but you get the gist) Good tip, thanks for sharing.
ForkTru - Fork Alignment Tool Quick and easy to use tool for aligning front forks to ensure they are parallel from top to bottom Knurled adjustment screws for easy setup Reduces stiction and improves the performance of your front suspension Reduces seal and bushing wear Fits most MX and Off-Road motorcycles (does not work on most sport bikes due to large brake rotor diameter and 17 inch wheel diameter) Will work on 27 mm - 62 mm fork legs and tubes Works on forks that are 140 mm to 220 mm on center Patented design
To make sure the axle doesnt pull the forks together when youve tightend them dont you screw it into the left fork leave the right side clamp bolts undone push the front down 2-3times to square it up then do up the 8mm clamp bolts?
you are comparing my apples to your oranges. and yes [it does make a difference] on the fork type (uber-common) i described. and my reply was to an older gen of said forks semi-tongue in cheek. so RELAX. bingo...called floating the axle. if the leg is pushed out or sucked in towards the hub you'll burn a bush and the chrome. and like an aging bonehead i forgot to mention this important step. DOH! i'd be curious to see his internals...if the dampers/rods lengths inside are incorrect then one leg wont extend all the way. some forks like showa TC are very sensitive to this and have a very specific OAL spec to adhere to on assbly.
Can you explain why some forks can have all the damping on one side and the spring on the other (difference of hundreds of pounds of force) and not have stiction issues, but a few mm difference in spring preload (no more than a couple pounds of force) is somehow going to cause stiction on KYB OC forks? Both forks have essentially the same bushing and guidance design.
FYI, to the best of my understanding they have "shared damping" (comp and rebound on both legs), just individual adjustment of comp and reb, so not really SFF. Presumably they will be slightly unbalanced once you turn the clickers, but that'll be a small variance relative to the overall damping level. This is only based on the teardown videos I have seen, as I have not had a set of 4CS forks apart myself (yet).
My tuner told me the same thing. They both have comp and reb valving with minor adjustments made on the dial.
