help with forks

Joined
Dec 29, 2006
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#1
ive orderd up xr 400 .40 springs and need to know the score with the spacer.ive done a search but need it in a nutshell as what to do.the spacers are what,4 or 5 inches long stock.if i bin them how long do i make the new ones because of the longer size of the xr springs.ive had forks apart and took out springs to change oil,was straight forwad using manual,i just need to know the size to make spacers before they arrive so i can change springs as soon as they arrive.thanks guys for any help.
 
Joined
Aug 24, 2006
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#2
I did the exact same swap as you this winter and only preloaded with 2 washer (a little bit less than 2mm each). With the xr springs being longer it seems that in most cases what ever length spacer you add in is the amount of preload that you'll get. It was in my case anyway.
 
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Oct 21, 2002
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#3
hi there, check out the justkdx site as there was an article on there about making spring spacers. but in a nutshell the main points with spacers is that you have to calculate the length, and the spacer length is not the same as the preload length (well sometimes it might be but thats just chance..)
to get the spacer length you need to subtract the spring relaxed length from the fork internal length when assembled (this is the available length that the fork spring can fit into the fork when the cap is on the damper rod but cap is not screwed onto the fork body) sometimes with xr or aftermarket springs this will be a negative figure.
then you add the preload amount you want to use say 10mm (to get this figure you are suposed to work this out from the amount of fork sag when everything is put back together, but a lot of people just try preload in the 5-15mm range...)
so finally by adding the difference between the fork length and the gap you want them to fit into, plus your preload amount you get the spacer length.
in my case with xr springs my spacers ended up being 10mm long from memory.
hope this helps,its a hard thing to explain without pictures or a diagram but if you do a search on here you will find more info or some links.
 
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Dec 29, 2006
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#4
ok thanks guys,i think i will try 10mm 1st and see how it feels.i dont race or anything yet but they should be 10 times better than they are now which is the main thing.i tend to crash more than i should because they dip way to much when in ruts ect.thanks again for your help.
 

blackduc98

Damn Yankees
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Dec 19, 2005
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#5
It seems that not all XR springs are created equal length-wise. It doesn't take long to cut a spacer, so I would wait till your actual springs arrive. For a starting idea of spacer length you could use the following equation: stock spring length + stock spacer length = XR spring length + XR spacer length. Then go thru the sag-setting exercise to fine-tune your preload.
 

blackduc98

Damn Yankees
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Dec 19, 2005
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#7