Fork Spring Preload | GTAMotorcycle.com

Fork Spring Preload

inreb

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Changing the fluid, forks fully extended, the cap blew thru the window and into the neighbours front yard. Measured preload at 54mm. Seems kind of much. I might ruin the threads putting the cap back on. Is 2+" preload normal or has somebody been in there? I'm going to cut 10mm off anyway. (BMW R100GS)
 
Very soft springs can have to be compressed quite a ways before they reach normal rider-aboard load, and if they are dual-rate springs (part of the spring is very tightly wound and the other part is much more open - a common OEM design) the initial rate can be pretty soft. But 54mm sounds excessive. It's a little late to measure it now, but do you know what the front rider-aboard sag was? How much total front fork travel do you have?
 
The stock spacers on the ol' FJ are close to 2". I also thought that a PO had messed with it until I looked up the OEM part.
 
I was not able to get preload specs or spacer length from either of the 2 manuals I have. I was initially shocked by the amount of preload tension. Subsequently I have been able to unearth the specs via google. They are in fact correct. I have some schedule 80 plastic pipe on hand so cut new ones 10mm shorter. Was still dicey threading the caps back on. None of my other basic damper rod forks have any more than 15mm preload hence my alarm. Thanks guys.
 
Ok.
 
Changing the fluid, forks fully extended, the cap blew thru the window and into the neighbours front yard. Measured preload at 54mm. Seems kind of much. I might ruin the threads putting the cap back on. Is 2+" preload normal or has somebody been in there? I'm going to cut 10mm off anyway. (BMW R100GS)

This sounds like every experience I've ever had pulling fork caps... I know I'm gonna catch one in the face one day
 

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