showa 47mm fork stiction 05 rm250

Got an 05 rm250. Forks have been harsh since I bought the bike. I have noticed that the forks have a lotof stiction and very stiff. Springs are .44kg has new pivot works bushings and seals. I weigh 200lbs. I'm running .4mm float and very soft valving (enduro/rock setup). Bleed stack is flipped and I'm running a bleed face shim on the base valve. It has rg3 base valve piston. Not sure on exact stack. Oil height is 300cc. 5wt maxima fluid. I have loosened everything-triple clamps,clamp lock nut,wheels,etc-still has stiction. I have some wear on the damper rod coating,but cartridge seals and damper rod extends and bleeds perfect. Could it be a bent fork? Not sure how to rule it out or what else to look at. Any ideas appreciated. Also-fork never bottoms even with low oil and light valving-always an inch or 2 left on fork that isnt used. Maybe iI have wrong springs? It's stiff until a larger hit and then responds unpredictable. Feels like its bound up until large enough hit overcomes stiction. Thought about buying crf250 forks and swapping bottom lugs but not sure if its doable.

I had some aftermarket bushings and seals that left a lot to be desired.

Ive always run oem Honda bushings and seals on my suzuki, they are top quality showa stuff without the suzuki price.

Take the inners out and see if the tubes will slide freely

I find a lot of the older Showa forks I see, the cartridge seals arnt leaking but feel very knotchy and not very smooth when bleeding the cartridge up, I don't think this would be all your problem, but if your putting new parts Into the fork, then cart bushes and seals might aswell be done aswell, just to eliminate that, and doesn't take very long to do either.

I had some aftermarket bushings and seals that left a lot to be desired.

Ive always run oem Honda bushings and seals on my suzuki, they are top quality showa stuff without the suzuki price.

Take the inners out and see if the tubes will slide freely

:thumbsup:

Check for bent axle.  Should spin freely and smoothly in the lugs with the wheel out.

 

These Suzuki spec Showas are REALLY weak and low quality I've found.  The tubes bend easy.

Think its the tubes or bushings. Axle spins freely,forks are aligned. Forks never felt good but not this bad. I'm comparing to shows sff spring fork so maybe it's unfair comparison

I'm replacing the tubes on mine entirely.  I've chased this friction issue on my RM around and around and determined that it's gotta be the tubes.

Try removing springs and cartridges then install forks in triple clamps and front wheel then cycle the fork thru its travel if it is the fork tubes you will feel it bind

I've tried that before and it checked out fine.  It can show up a lot more once the wheel is on the ground and the rake angle is applied to the forks.  That's where the difference was with mine, but I think mine were bent from a bad slapdown landing from the previous owner, so both forks bent forwards uniformly.

That is exactly how mine are. Off the ground they feel better. Put both wheels on the ground with the weight and angle and they feel stiff and sticky.

Yep, been through the alignment on mine a dozen or so times. Small improvements but nothing to get them feeling like they should.

Roll the tubes on a bench and you will see if they are bent

A FLAT bench, yes.  Gotta find one...

 

That works for the lower tubes, but not really for the uppers.

Ah uppers ,what about a metal rule all the way up inside them ?see it they move away from the flat edge of the rule ?

Does anyone have a spec for amount of bushing/stanchion slop allowed in these things?  If it's excessive on certain ones, that could explain the binding when they're on the bike and get pushed at an angle, but feel fine off the bike.

Well if the forks feel fine on the bike without the springs and cartridges installed and you a still having binding issues the next step is to check it using the motion pro fork alignment tool and if that doesn't show anything then you need to check the lower and upper legs separately with a dial gauge and 2 v block like when you true up a crank the Honda device manual describes how to do it.

Ok. Checked tubes making sure they are straight. From what I could tell tubes are straight. So... it has to be the bushings. Going to order skf bushing and seal kit. I do have skf seals and bushings in my rmz250 sff forks and that bike has the smoothest forks I've ever owned. This pivot works stuff must have different tolerances or something. Only time I ever used a pivot works seal and bush kit was kyb aos forks for a friend on an 05 yz250. Oddly-i remember him saying the forks felt harsh after the rebuild. So maybe it is something with the pivot works kit? I did see that other have had similar experience with pivot works seals adding more stiction but nothing said on the bushings. The seals are definitely sticky and just by dropping the wipers you can feel less stiction.

If anything-this has been good lesson for me on what and why stictkon is a concern. The fork has to overcome the sticking before can move. By pushing on the forks,I would say its 15-20lbs of force to overcome this. Not good for woods riding. Not reactive enough and those first 3 inches of travel in rocks are very important.

I just rebuild a Showa and my friend provided Moose seals and bushing, just when sliding the seal on the lower tube you can feel the sticktion. With SKF seals the lower tube slide freely by its own weight, it is far from that with the Moose. Tomorrow they will be back on the bike and I know already the result !

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