entropy
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posted January 31, 2010 04:53 AM
 Edited By: entropy on 31 Jan 2010 16:31
seat pressure: using bathroom scales
basic start, a place to put the scales
The base with blocks to level the head
a base to put the head
ready to test
Test (previous test was 79.0)
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KZScott
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posted January 31, 2010 07:16 AM
Thank you!!
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
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Shane661
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posted January 31, 2010 04:07 PM
Thanks for the pics!
So, it's just a matter of using the blocks to make sure the press is in alignment?
I'm still a little unclear on the rest of the process.
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entropy
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posted January 31, 2010 04:53 PM
quote:
Thanks for the pics!
So, it's just a matter of using the blocks to make sure the press is in alignment?
I'm still a little unclear on the rest of the process.
yup, blocks just make sure all is stable and drill press is aligned with the valve.
hard to see but there is a cut off valve stem in the chuck.
just activate the scale and come down with the chuck/valve stem until it hits the tip of the valve in the head.
Press until the valve just unseats.
works like a charm
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Shane661
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posted January 31, 2010 04:58 PM
Edited By: Shane661 on 1 Feb 2010 01:00
Ok, got it! A drill press is on the list...I've looked at some of the Grizzly ones, and a few Craftsman as well...
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tcchin
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posted January 31, 2010 06:04 PM
Technically, you don't even need a drill press. Just a 2x4 hinged to a wall stud will do the trick. Maybe a cut off valve stem lodged into the 2x4 to simulate the chuck... You're applying quasistatic pressure to the valve spring, so you don't need to worry about maintaining parallelism through the arc of the lever travel, as there won't be any lever travel. This might be a serviceable short-term, cheap solution until you can afford a quality drill press. Drill presses are something where quality maps to price pretty closely.
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KZScott
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posted January 31, 2010 06:58 PM
I bet I could make that in a few min tops Tim...
I also see what i was doing wrong before, i didnt have the head positioned properly. Karl, do you have a chart for how added shim affects seat pressure? is it a linear relationship? where are you getting your shims?
thx 
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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osti33
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posted January 31, 2010 07:20 PM
Good pictures Karl. Thanks!
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tcchin
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posted January 31, 2010 10:02 PM
Linear springs have a linear relationship between force and displacement (f=kx). Progressive springs have a non-linear relationship and do not respond well to shimming. They do add value when trying to avoid harmonics, as progressive springs do not have a simple harmonic frequency like straight-rate springs. Most performance springs are linear, because they can be adjusted for seat pressure more easily.
I get my shims from McMaster-Carr.
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entropy
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posted January 31, 2010 10:41 PM
Edited By: entropy on 1 Feb 2010 06:44
Tim, isn't that (F = -kx)?? 
adding a .060 shim will increase seat pressure about 12#
adding a .015 shim will increase seat pressure about 3 #
I only do valves #4,#5 bc I am lazy and bc, I have done it sooooo many times, and not seen any difference in individual springs.
EXCEPT!
Before taking measurements, line up all yr springs on the bench and assure they are all the same height...
Yesterday I opened a new pack of Carpenter springs and one of the inners was at least 1/8" shorter, and that one had 9# less seat pressure than the others
Tim,
I like your idea of a 2X4 hinged to the wall better than the drill press, much more flexible. 
time for me to go to garage and set lash
(38F - shit!)
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tcchin
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posted January 31, 2010 11:01 PM
Edited By: tcchin on 1 Feb 2010 07:03
quote:
Tim, isn't that (F = -kx)??
Sorry - I was assuming that the digital bathroom scale was only capable of displaying |F|...! Yeah, that's it!
quote:
Tim,
I like your idea of a 2X4 hinged to the wall better than the drill press, much more flexible.
It can double as a bead breaker when you're not doing valves!
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Shane661
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posted February 01, 2010 02:50 PM
Edited By: Shane661 on 1 Feb 2010 22:51
quote:
Technically, you don't even need a drill press. Just a 2x4 hinged to a wall stud will do the trick. Maybe a cut off valve stem lodged into the 2x4 to simulate the chuck... You're applying quasistatic pressure to the valve spring, so you don't need to worry about maintaining parallelism through the arc of the lever travel, as there won't be any lever travel. This might be a serviceable short-term, cheap solution until you can afford a quality drill press. Drill presses are something where quality maps to price pretty closely.
I really want a drill press, since I actually do drilling and stuff.
I'm just having a hard time picking one out!
Karl, what's that tray holding your valvetrain parts?
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entropy
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posted February 01, 2010 10:46 PM
quote:
Karl, what's that tray holding your valvetrain parts?
8 hole muffin tin, my wife never noticed they were gone
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