Mk3 Roadholder Fork Sag Measurement

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p400

p400

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I am trying to establish a good/bad status of my fork springs, 1975 Mk3 Interstate.
I would like to avoid tearing the forks down and measuring the spring.
Is there a good/bad measurement of the Roadholders some where?

I have a dimension from my forks spanning from top of the chrome cap to bottom of the rubber fork boot. = 439mm
No rider, 2 gal gas, Interstate tank/seat
my pic is not displaying the 439 but it moved with one hand photo.

20200918_Mk3Sag2.jpg
 
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No rider
Looks like about 143mm of exposed fork chrome - between bottom of lower triple and top of rubber boot.

I was hoping there would be some data over the past 50 years.

Maybe some Mk3 Interstate owner has fitted new stock fork springs?

I rolled my Interstate and put it on side stand , still measures 143mm exposed.

1975MklllInterstateForkSagSm.jpg
 
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Anyone have a tape measure and a Norton Interstate with about 2 gallons on a side stand?
 
73 850 Interstate, new original type replacement springs about 18 months and 10k miles ago. Has about 5 gallons of fuel. Measured several times. Comes within a couple mm of 160 each time from bottom of triple tree to top of boot
 
JUst measured my Mk3 Roadster, 2 gals of gas, on sidestand. Original stock springs, "sag" measured at 168 mm per your method:
bottom of triple tree to top of boot
Jaydee
 
I have my Mk3 off the workstand and able to more easily bounce the front forks.
Springs and stiction considered, My Mk3 can bounce to 150-143mm range.

Mk3 Roadholder Fork Sag Measurement
 
My mk2 is on the lift right now with about that much fuel. Stock springs (which were out for ~20 years when i had progressive springs in) and Lansdowne dampers.

I get 163mm, but not on sidestand. But i would expect more than that on the sidestand.
 
713mm from top of triple to axle center, which is probably a better measure due to the dustcaps on the sliders.
 
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