Installing XR400 springs

saveaux

Member
Jul 20, 2005
140
0
.38 XR400 springs. I don't have a manual (commence flame) but from what I've read this seems pretty straight forward. I've already removed the old springs (pull them out fast and see how much oil you can fling all over yourself.....no really...do it on both forks too...no....really) and have the tubes upside-down draining in a bucket. I've already bought scheldue 40 1" pvc. The new springs appears to be 1.5" longer than the old springs. With that being said do I just cut a piece of PVC to the length that would add up to the old spring plus the old spacer? I've read that alot of people use a 1.5" spacer.

By leaving the forks upside down in buckets (I dumped the majority into an oil container before putting them into buckets) is that enough to get all the old oil out? Due to time contraints I'm leaving them sit like that over night. As long as that should be enough I will just pour 550ml back in? I did measure how much came out (around 525ml) but there was so much oil left on the springs when I pulled them out that I knew the numbers would be off. I bought B&M Trick Shift ATF, hope it works.

I've changed fork springs in my mountain bike before and I must say that has been a MUCH easier job so far. From putting the bike up on its stand to having the springs out and draining oil it took 45min. If I had to do it again that time could be shaved nearly in half (I took alot of stuff off that didn't need to come off, like handlebars, numberplate, WER damper)

oh ya my questions:
1. Should new spring + new spacer = old spring + old spacer?
2. Leaving forks upside down in buckets over night, is that enough to drain all oil?

p.s. that old oil smells worse than GL5 and is NASTY!
 

XRIowa

Member
Dec 8, 2004
54
0
Sounds good to me!! I did this with my old XR springs and I just cut the PVC so everything was equal. (lenght wise) works great I also ran 10wt oil!! Best mod on my bike thus far..
 

John Harris

Member
Apr 15, 2002
552
0
If I understand your proceedure correctly, you will wind up with the same preload on your new springs as you had on the old stock ones. Is that what you want? The better? way is to put the springs in the forks and screw the cap onto the center rod, then measure the uncompressed distance between the top of the springs and the cap for the spacer. Add to this dimension the amount of preload you want on your XR springs, usually 3 to 10 mm and then cut your spacer. Be sure you have the rings/caps on both ends of the springs (from the stock springs) before you do your measuring and then of course use them in the installation. To help you out--if I remember correctly with 10mm of preload my spacers were about 1.5" long. Easiest and best modification you can make to your KDX to keep you out of ER. Cheers John
 
Cookies are required to use this site. You must accept them to continue using the site. Learn more…