Checking for correct fork movement

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SteveBorland

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As part of my front fork fettling project, I'm trying to determine what's acceptable play in the fork stanchion - slider assembly. The notes I'm using mention that there will be some play, even on new components, but the question is how much is acceptable?
With the stanchion at it's fullest extension (i.e. min. overlap), it actually sticks. If I move it slightly down (about 1/2 inch or so), I can just detect a slight rocking. I've tried with 2 different sliders and 2 sets of the bronze & steel bushes, and I don't really feel any great difference from one setup to the other.

Reading through some of t he other topics on forks, it seems that there is quite a variation in the actual fit of new components, even if they are sourced through Andover Norton, so I'm wondering if what I have is as good as can be expected?

Should the stanchion travel smoothly through it's entire stroke, or is the last bit of travel unusable?
 
I found slight fro/aft wiggle 1/16"-1/8" at axle end from the slight slack of top bushes on stanchions as main source of slack that can make fork below axle become blurred while racing to max in tights on rough pavement but didn't notice anyting affecting handling/taction while out doing fasso modern sport bikes - my handy race tire and supsension set up SV650 included. Sticking near full extension implies springs rubbing inside stancions more than bushes hanging. I went through 3 sets of bushes trying to remove this slight slack but new bushes beaten back really round on the stancions were looser than the new bushes so use new bushes as drift or spacers to hammer on stuff to remove or install. JMS teal colored composite bushes took all slack out of Peel's old sliders yet slides slick even dry.
 
Once the sliders have seen a few miles they wear in the center area, one BIG reason is the oil get's contaminated with spring shards , these rub off when the spring becomes fully compressed. this compression cause's the spring to bare against the internal stanchion wall.
Not a lot of rubbing turns the fork oil into cutting fluid.
Combined with lower iron bush and excessive internal pressure due to braking ,this slowly rub's the alloy oval...the top and lower slider bore stay's round.
New bush's will feel "good " at the top and bottom ,but slack in the center.
Only new parts will restore the tolerance , Or ream out oversize and make up be-spoke over size bush's /
I like peek .expensive and tricky to get the two thou clearance . But it will last another 30 years..just change the fork oil yearly or 10,000 miles.
i have seen some old manx sliders ten thou worn.
Some stanchions are not in spec, and i have found the bush's tapered.

Also check the stanchion bottom bush is concentric with the main diameter , cheapo ebay stanchions can be center-less ground . resulting in the bush's running out of alignment. This cause's binding at full extension . It's a world of woe :!:
 
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