Cutting my 1993 EX500’s Fork Springs
June 17th, 2007 ydantThis is meant to serve as a simple step-by-step instruction for cutting the springs on an EX500
in order to change the spring rate and feel of the motorcycle’s handling. This is a poor excuse
for getting the proper springs, and is not an exact science. More expensive options will potentially
provide significantly better (and more predictable) handling due to the springs not necessarily having
linear response and being more accurately engineered. Also keep in mind that spring characteristics
change over use, so any calculations you make will be affected by your specific springs. Finally, the
spacers used in this example have the potential of failing, which could lead to disasterous results.
This was originally posted by me in this thread
on cutting ex500 springs. I wanted to compensate for the lack of good pictures available on the
topic. There is a wealth of information on this subject in that thread and in others on that
board, so be sure to read up on everything.
The original post follows.
I did this today. Drained out maybe 50ml of oil - which explains why I was bottoming out under moderate braking. There’s definite a difference (and, I think, an improvement). At the very least, I can lock up the front at 30mph without bottoming out - a huge improvement! The roads were too dark when I went for a test ride, so it was hard to really test the change out.For other people who can’t really visualize things, I took some pictures. Hopefully these help!
Necessary Parts / Tools
- fork oil - about 800ml, so get the liter bottle
- a gear puller for removing the plug
- a couple of feet of 3/4″ PVC pipe (you won’t use it all, but it’s best to have extra)
- something to cut the springs - I used a dremmel and a cutting wheel
- 6mm allen wrench to remove the handle bars
- 10mm socket/wrench to remove the drain plug (1st gen only)
Step 1 - Remove handlebars
Get rid of the two bolts pictured below. Pull the caps off first, of course.
Step 2 - Remove the cap on the shock
This is where the gear puller comes in handy. You could do this with a screw driver, but the gear puller is SO much easier. Thanks, FOG.
You’re pushing it down to get to the metal ring that holds the cap from popping out. Once the cap’s out of the way, remove the clip:
Step 3 - Remove the cap
Now that the clip’s out of the way, unscrew the puller. The spring will push the cap out:
Step 4 - Extract the spring
There’s a lot of it - 20.1875″ worth on my ‘93. The next generation has a bit shorter spring.
Step 5 - Remove the oil (drain, pour, or suck)
If you’re lucky enough to have a drain hole, use it. If not, follow FOG’s instructions (search) on putting your own drain plug in. Or suck the fluid out.
Step 6 - Cut the springs
Use the calculations from the thread on cutting ex500 springs (original spring length / new spring length X original spring rate = new spring rate) to figure out how much to cut. It’s easy enough to do again but hard to undo, so be conservative.
Step 7 - Cut the spacer
Again, read the rest of this thread (and the cutting spacers thread as well).
Step 8 - Refill with oil
Pour in the proper amount of oil. Read the rest of the thread and your service manual for the proper amounts.
Step 9 - Reassemble
Spring, washers, spacer, plug, and push it all back together. Put the clip back in.
