Shimming KX500 fork springs

[ShanMan]

I was wondering if anyone here had ever installed spacers into the fork tubes to preload the front springs? I intend to get the suspension reworked to accomodate my weight (240 vs. 185 for the previous owner), but there is no time between now and this weekend. Anything I can do to raise the spring rate would help. Thanks in advance.  

[moburki]

i think you can space them some. i don't know if the stock springs collapse all the way, if so, there would be a problem. i would be weary to do more than an inch of spacer.
mo

[Rick]

Yup, I have preload spacers in right now, but nothing near an inch.  I have a total of about 1/4 inch preload in the front, and this is with .43 springs.  Not sure I would be comfortable with much more than this.  Since you are going to have the suspension reworked shortly, you might try and drop for the forks into the tripple clamps about 1/4 inch.  This will push the front end higher while riding, and my be just enough to keep you from feeling like the front is lower than the back.  It will, however, change your steering characteristics, so there is certainly a tradeoff.  The combination of small preload spacers, and dropping the forks my just get you from now until the suspension is tuned.

Rick

[ShanMan]

While I am asking about suspension do's and don'ts...what is the recommended air pressure for the fork tubes? Perhaps more importantly, what do you guys run? Thanks in advance.

[moburki]

my forks have bleed holes only. that is for releasing any pressure that may develope from temperature, and air pressure (altitude). i have ten millimeter spacers in my forks now, and its not uncommon to use up to an inch or so in road bike forks. ten millimeters is just below half an inch, and that was reccomended by race-tech.
.02
mo

[hughes]

Sorry for dragging up an old post. But I would like to shim my fornt spring to have alittle more pre-load for my weight. Re-stroing my 87 kx500 is breaking the wallet for now but new springs are in the future plans. This is the idea I had for shimming the springs. When I remove the top cap their is a spacer, collar, and another spacer that rides on top of the spring. If I install a non-plated steel washer between the spring and the spacer this would add more pre-load to the spring when I re-install the cap What do ya'll think. I know spring is the right way to go. But for now maybe this can help. Thanks

[Rick]

This was a common practice on pre-1990 bikes.  However, while a little preload will help, if you add too much, the spring will fully compress before your forks bottom out.  I can only surmise the kind of damage that will result.  

Next question:  How much is too much?  I am sure there is a way to measure all of the spacing on each coil and add them all up to determine the amount of total compression and then compare this to your total available fork traval from fully extended to fully compressed, but I have never tried this.  Given the cost of forks, springs from Race Tech are pretty cheap in comparison.

Rick

[teamgreen500]

The only way I've found to measure fork spring "True Travel"is to compress the spring inside a Lexan tube and measure the extended v. compressed lengths.

Rick makes a good point. Get  the info B4 you add more than 1/2"

Good Luck

[hughes]

Thanks Guys,

I am looking at adding no more than the 1/2. More like 1/4-3/8 of an inch. Just need to talk the boss into letting me drop some $$ on new springs. Thanks