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Hingley

1990 Fork Spring confusion

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I am in the middle of installing  another set of front forks and changing the fork oil on my 1990 VFR750 and I am interested in learning about stock springs and after market springs.

When I removed the springs in my 90 I found the springs are 18" long with no marking, in addition I have a set of donor foks that I was going to install and found they too were 18" long with no markings. Both sets of forks have what looks like Steel exhaust pipe spacers on top of the fork springs. When I went to the shop manual Honda lists the fork springs as being 16.28" long but no mention of how long the spacer should be.

So how do I figure out what kind of springs I have and what the correct length of spacer they should have, is there even a way to know who made them?.  Also for what it is worth is there a way to find out the length of the original spacer?

 

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The washers are just an interface between the spring ends and the spacer so they don't rub weird and create contaminates.  You want to have the spacer length to give the springs approx 20mm of preload when they caps are fully installed.  Of course some applications/preferences will require different preload numbers, but that is a fairly standard starting amount given that the springs are the correct rate for your weight/riding style.

 

There are some instructions on DMr and RaceTech regarding setting static and race sag to help determine if you have the correct spring rates.

 

And it is very hard to identify springs, they usually don't have markings.  Check each end that has been ground flat for any stamps or scribes.

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This is getting interesting. I have three different front forks for the 3rd gen VFR and every one of them is different. They all have 18" ( 458mm ) springs, not the original 16.28" , but one has a steel spacer 25 mm long, another has a plastic spacer 25 mm long and the third has no spacer, to add to this they all differ in the number of spring washers and slotted spring washers. I am curious does anyone know the length of the original spacer and the material it is made of, I assume it is steel but you never know

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No spacer?  Poor man's lowering kit?  Yikes.

 

Original are steel.  I have a set of 1991 forks that need to come apart that I believe are 100% original.  I will try and get them apart before my shoulder surgery on Wed.

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The OEM spacers were indeed steel, 50mm long--but it doesn't matter, because unless you weigh 120lbs and like a plush ride, you should tune the fork pre-load to your own circumstances anyway.  The FL-FM bikes didn't even have pre-load adjusters, so the only way to adjust the sag is to experiment with the spacers and washers.  (Pre-load adjusters from other 41mm forks do fit, btw.)

 

Ciao,

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