KYB SSS midvalve collar and recesses

[MartyMOOSE]

What measurement do you guys get when you measure the recess on the piston that mid valve collar sits in mine measures at 1.03mm?  I get the Collar at 5.27mm (most say 5.3mm) Also on the backing plate I measure it as 2mm deep ? Does anyone concur ?? If so my feeler gauge float measurement SUCKS ??

 

MM 

[GP]

I get 1.02 and 5.26 on my set. I don't use the gauge method, prefer to calculate the total stack and subtract from the free space.

[MartyMOOSE]

6 hours ago, GP said:

I get 1.02 and 5.26 on my set. I don't use the gauge method, prefer to calculate the total stack and subtract from the free space.

Cheers I'm not using gauge anymore either its too in accurate. This is the second set I've found I'm out with. 

MM 

[dwb79]

5 hours ago, MartyMOOSE said:

Cheers I'm not using gauge anymore either its too in accurate. This is the second set I've found I'm out with. 

MM 

What do you think is causing the difference between your calculated and measured float?  

 

[MartyMOOSE]

27 minutes ago, dwb79 said:

What do you think is causing the difference between your calculated and measured float?  

 

I think its due to my feel with the gauge maybe I'm forcing it in to hard and distorting the shims a little we are only talking small amounts here. Do you measure or calculate DWD or both. 

 

 

[dwb79]

I've tried both techniques and much prefer the feeler gauge method.  I feel there is less room for error by taking one measurement compared to taking four separate measurements and calculating.  I also think that a feeler gauge measurement is an actual measurement of the final build taking into consideration any compression or stretching of materials, any imperfections in casting/machining and is a great method for ensuring quality control.

[MartyMOOSE]

20 minutes ago, dwb79 said:

I've tried both techniques and much prefer the feeler gauge method.  I feel there is less room for error by taking one measurement compared to taking four separate measurements and calculating.  I also think that a feeler gauge measurement is an actual measurement of the final build taking into consideration any compression or stretching of materials, any imperfections in casting/machining and is a great method for ensuring quality control.

I was miles out ?? Do you use two feeler gauges one on either side or just one ? 

 

MM 

[mlatour]

With Race Tech G2R Gold Valve kits there is a 'calculated' method

with a list of packing shims to obtain the desired float gap.

Following instructions, I have never gotten the same calculated and actually measured results.

 

First making sure all components in both forks have the same measurements:

collar height, collar recess, cup height, piston thickness etc. (some will no doubt require lapping),

I've found the '2 feeler gauge' method more repetitive than anything calculated 'on paper'.

[GDI70]

I use 36 to 40 in lb with my in dial torque instrument. Then I can use 2 feeler gauges,  or 2 shims with slight drag, to measure float under torque. 

[GP]

Next time I do one I'll torque the piston to the tap without the mid stack and measure the free space, compared to the individual parts.  How much variation under torque do you see? 

[GDI70]

Maybe .15 float could be a .135 under torque.  That's a measurement I've got,  but there could be a variance if piston materials differ; brass race tech mv vs. stock.

Edited November 13, 2017 by GDI70
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[GP]

More significant at tighter floats I see.  Working in the .4 to .45 range with stock KYB pistons less of an issue.  I will measure my particular parts, thank you.

[dwb79]

21 hours ago, MartyMOOSE said:

Do you use two feeler gauges one on either side or just one ? 

 

MM 

Mostly I use a feeler gauge in one side while holding the other side of the shim stack down with my fingernail, to make the shims parallel with the piston.  Repeat at 180 degrees.