Shimming valves for spring length

[Dodgyiti]

Every valve needs about 2mm due to 3 angle valve grind/new valves/inner and outer springs etc.
The measurement changes when I dummy fit the valve collets and ali end cap, take the slack out with my fingers (Trying to pull back the endcap as much as I can)and put the vernier on it -to when I refit the whole valve and springs and measure it -> by about 1.4mm. The factory manual shows the measurement being done on a drawing with the ali cap and collets on the valve and the measurement is done to the head face and under the top lip of the ali end cap. With the assembly of valve/springs etc in place it is difficult to measure under the top lip of the spring retainer because the spring is in the way. But it is different. Any thoughts oh wise ones?

[Pixie]

Try measuring with only the inner spring installed.
This may give more room to make the measurement

[Brian d marge]

As per pixies advice , the distance is there to give seat pressure , and springs are linear as to force

good luck

stephen

[roadracingoldfart]

The graphic you posted shows the distance from the TOP of the thrust washer to the UNDERSIDE of the top collet retainer flange.
Maybe i read your post wrong but i think your measuring from the top of the ALLOY valve stem base.
A steel thrust washer is approx 0.80mm - 1.00 mm thick at the most so is that what your asking ???
Also when the collet is forced under spring pressure into the retainer flange it will be forced into it more than what your finger can do.
Are you just trying to work out the free lenght of a new valve ?. If so then just get a small divider into the gap and measure with that, then compare with a vernier or micrometer.
Looking at the photo i see what you problem is. Measure rite to the top of the collet retainer and then subtract the retainer thickness from the equation .

[JimBob]

Every valve needs about 2mm due to 3 angle valve grind/new valves/inner and outer springs etc.
The measurement changes when I dummy fit the valve collets and ali end cap, take the slack out with my fingers (Trying to pull back the endcap as much as I can)and put the vernier on it -to when I refit the whole valve and springs and measure it -> by about 1.4mm. The factory manual shows the measurement being done on a drawing with the ali cap and collets on the valve and the measurement is done to the head face and under the top lip of the ali end cap. With the assembly of valve/springs etc in place it is difficult to measure under the top lip of the spring retainer because the spring is in the way. But it is different. Any thoughts oh wise ones?

I think you will find the drawing is for reference.
Check the ali retainers and collets for a good fit. The collets can create little ridges in the alloy so either get some new ones or lap them. If they are worn more than a few thou toss them.
Assemble as per the photo, give the stem a couple of taps with your soft hammer, to make sure the collets and retainer are seated and measure.
If you really want to do it "right" you will be setting spring pressures rather than spring length, but for a stock street bike this is good enough.
The Guzzler has a fairly large tolerance for such things so you dont have to get too carried away unless you really want to
cheers

[Dodgyiti]

I think you will find the drawing is for reference.
Check the ali retainers and collets for a good fit. The collets can create little ridges in the alloy so either get some new ones or lap them. If they are worn more than a few thou toss them.
Assemble as per the photo, give the stem a couple of taps with your soft hammer, to make sure the collets and retainer are seated and measure.
If you really want to do it "right" you will be setting spring pressures rather than spring length, but for a stock street bike this is good enough.
The Guzzler has a fairly large tolerance for such things so you dont have to get too carried away unless you really want to
cheers

Thanks for that JimBob and to everyone else.
The idea of only the inner spring was what I tried and it was perfect. There was no bias in measurement as I got a reading either side of the spring retainer and it was not skewed- so a clear reading then after reading JimBob's post I removed a tiny burr from 2 out of 4 retainers and remeasured the lot, putting the retainer clips in the numbered and matched system like the valves etc.
The diagram shows one shim fitted, it is a .35 and I took that into consideration. The measurement is very exacting in tollerence- by less than .5 so that means to me it is important to be within.
With new valves, 3 angle grind and new springs, I expect some 'settling' and want the minimum tollerence spec. And after all that I (and some top machining and balancing people) have done to this motor - everything else is blueprinted and tweaked so it is best practice to keep up with that theme.
I know Guzzi's handle all sorts of atrocities the factory, let alone the owners put them through, kinda like this bike that has been rebuilt from what I can tell- twice, and no bastard balanced the crank, and it was shockingly out of kilter, needed a fat plug of mallory on one end just to bring it up to needing balancing!
So I am doing my best to get the job right this time and will enjoy the fruits (and berries) for years to come, touch wood.
After careful check/measure/check again I will have ordred enough shims to be exactly within the minimum tollerence.
Thanks again folks.