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Inner/Outer Fork Tube Play

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Assume a brand new fully assembled KYB fork mounted on the triple clamps. No front wheel, no brake, nothing attached. If you grab the outer fork tube at its lowest point and then grab the inner tube at the bottom of the lug and then wiggle the lower tube front to back and side to side, should there be any movement/play? If so how much should the lug deviate in its movement? Wondering if it should be zero play (tight) like the wrist pin in a piston or tight like the non-vertical movement of the crank in its bearings.

When I perform this test, I get a couple milimeters side to side play measured at the bottom of the lug on the left tube and maybe one and a half on the right lug. The lugs are not loose on the inner tube, its the whole inner tune assembly has side to side play. The same play occurs if you compress the lower tubes an inch, they will still rock by the same amount.

The bike is a 2009 CRF450R and I just got the suspension back from being revalved. I did not do this test on the fork before I sent them out. The outer tubes were replaced with new coated tubes during the revalve.

Thanks in advance.

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I've never noticed any play like this on any fork I've seen but I'm not a suspension expert by any means

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Assume a brand new fully assembled KYB fork mounted on the triple clamps. No front wheel, no brake, nothing attached. If you grab the outer fork tube at its lowest point and then grab the inner tube at the bottom of the lug and then wiggle the lower tube front to back and side to side, should there be any movement/play? If so how much should the lug deviate in its movement? Wondering if it should be zero play (tight) like the wrist pin in a piston or tight like the non-vertical movement of the crank in its bearings.

When I perform this test, I get a couple milimeters side to side play measured at the bottom of the lug on the left tube and maybe one and a half on the right lug. The lugs are not loose on the inner tube, its the whole inner tune assembly has side to side play. The same play occurs if you compress the lower tubes an inch, they will still rock by the same amount.

The bike is a 2009 CRF450R and I just got the suspension back from being revalved. I did not do this test on the fork before I sent them out. The outer tubes were replaced with new coated tubes during the revalve.

Thanks in advance.

A fair amount, and as the fork breaks in, even more.

This is why fork alignment is so tricky. The fork(s) always drift and are sometimes pushed off to one side because of the spring pre-load.

FORK%20TUBE%20DRAWAING%20WITH%20SMART%20LOGO.jpg

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DaveJ,

Interesting diagram. It actually gives a range of 5-7mm mis-alignment due to tolerances. If I read that right, it would allow either side 2.5-3.5mm individual play so my 1.5-2.5mm non-scientific measurement is within spec. Thanks for the info. It's amazing there's that much play designed into the system.

Thanks again.

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