Author Topic: Fork tube orientation  (Read 616 times)

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Offline Kickstart

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Fork tube orientation
« on: June 12, 2021, 10:11:27 PM »
I'm rebuilding my front forks and I'm not sure which way to orient the fork tubes on reassembly.

I marked the front of the tubes before removing them from the bike, but then I wiped the marks away. :)
I believe the wear mark on the bottom of the tubes faces towards the back of the bike (see attached picture as to what I'm referring to).  Is this correct?


I'm also assuming it's best to install them the same way they we before... or is it better to spin them 180 degrees so there's a fresh surface where the tubes get the most wear?

Thanks,
Kickstart
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline Flyin900

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Re: Fork tube orientation
« Reply #1 on: June 13, 2021, 01:54:22 AM »
My guess is the wear is from the front of the fork area given the angle of the forks the thrust would be forward facing. That said if you want the wear reoriented then face it backwards in the slider. It may not make a discernible difference, as the internal part is likely worn too.
Common sense.....isn't so common!

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Offline 754

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Re: Fork tube orientation
« Reply #2 on: June 13, 2021, 10:43:53 AM »
First check if they are straight.. if slight bend put it so they are pointing ahead..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Kickstart

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Re: Fork tube orientation
« Reply #3 on: June 13, 2021, 11:07:24 AM »
My guess is the wear is from the front of the fork area given the angle of the forks the thrust would be forward facing. That said if you want the wear reoriented then face it backwards in the slider. It may not make a discernible difference, as the internal part is likely worn too.

I'm thinking the majority of the forces are straight up, and with the forks at an angle, the bottom front of the fork tube would get the most wear.. sure hitting a pothole will create strong (impact?) forces on the top/front side of the fork tube, and maybe that causes more wear than typical driving wear... or maybe the majority of wear happens when you apply the front brake, in which case the wear on the front/top makes sense... IDK


First check if they are straight.. if slight bend put it so they are pointing ahead..

Ah, thanks for the tip... I'll do that.
One of the forks had a 0.017" deflection, but my buddy and I got it down to 0.003" using a press.  The other is less than 0.002"
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Online bryanj

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Re: Fork tube orientation
« Reply #4 on: June 13, 2021, 11:20:30 AM »
Having done this for way toolong i canhonestluy say it dont matter a stuff
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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Offline 754

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Re: Fork tube orientation
« Reply #5 on: June 13, 2021, 11:34:16 AM »
3 thou is fine.. see worth checking.....right ? That kind of bend is not uncommon..
 The less its bent , the harder it is to tell..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way