'87 shock setup.

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DEATH_INC.
Posts: 5
Joined: Sat Nov 23, 2019 3:47 pm
Location: Auckland, New Zealand

'87 shock setup.

Post by DEATH_INC. »

If anyone is interested, I finally got the rear shock on My '87 500 working pretty well.
I'm 83kg and use it for MX, I'm also an older guy that had a massive crash recently, so no 100ft doubles etc, though i still launch it fairly well.
When I got it it still had the stock spring, but I'm guessing it had been re-valved, it wasn't very nice to ride, too stiff especially on sharp bumps and jump landings. It also lacked grip.
First up I run a 325lb 65mm id spring, with 5mm preload. I made adapters to fit this.
I use dex6 for oil,, it works very well, is a good weight, 5.7cst @ 100 deg, and is cheaper than shock fluid. It's also very slippery.
I use a program called Restackor to help with working things out. http://www.shimrestackor.com/index.htm
My first re-valve was much better, I almost halved the rebound damping from what it had, which it needed, but I actually made it too soft on the compression, and it was still harsh on square bumps. It had much better traction though.
These things have an interesting compression adjuster, basically a high speed blow off with a bleed.
I pulled it again to see what else could be done, and made an interesting discovery that I'd missed the first time, the port that goes from the main body to the adjuster is only around 2.25mm diameter, which Restackor told Me was causing the curve to be overly progressive.
So, what I have now is;
The port to the adjuster I drilled to 4mm from that crazy little 2.25mm.
I filled the bleed in the compression adjuster 'valve body' with Devcon (like JB weld) and re-drilled it to 1mm down from 2mm.
I added another 1mm of shims to the compression adjuster under the spring, to allow a bit more adjustment.
the valving is;
Comp;
5x38 0.15
36 0.3
34 0.3
30 0.3
26 0.3
23 0.3
19.8 0.3
17.9 1
26.5 0.4 these 2 last ones are the stock backing shims
40.8 6.5

Reb;
2*34 0.15
3*31 0.15
30 0.3
28 0.3
26 0.3
24 0.3
22 0.3
21 0.3
19.9 0.25
18 0.4
26.5 0.4 as above these are the stock backers
34.8 3
Rebound is at 10 clicks out, compression at 7 in.
It's now firm but compliant, and hooks up well.
:stretcher:

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