SV650SK6 - K-Tech Springs and YSS Valves Fitted

[aesmith]

Thanks. Yes damper rods were properly modified and sag set. That Youtube video is interesting. Clearly the guy is able to quickly judge by experience/feel, but what he appears to be looking for is to set the rebound as quick as possible while still staying deadbeat. That certainly seems the case for the front because it looks like he tweaked it until it only just stopped overshooting.

What I mean about the oil is that I'm starting from a known quantity, 32 cst. Once I know whether that's right or wrong in actual use I can replace with proper fork oil of the same viscosity, using that chart that's floating around. Saves buying oil at £15 per time only to find it's the wrong sort. Come to think of it if I wanted to go a bit thicker I could blend some hydraulic 46, but I don't have anything thinner.

[embee]

Don't know if these have been posted before, but I found them useful. I know you have YSS emulators, I have Debrix, but the principles are the same.
http://www.racetech.com/page/title/E...Tuning%20Guide
http://www.racetech.com/page/title/E...%20They%20Work


I found with the Debrix I needed to increase the compression damping holes in the discs, I use 2 holes 2.7mm dia in each disc but that's a bit of a personal preference thing.
I use Silkolene PRO 7.5W oil (around 36cSt at 40C), I did try 10W but found it too harsh.
The Debrix valve springs are a lot stiffer than the Racetech variants, so I don't know if the disc effective diameters are different or if Debrix just plucked a spring out of the air. I do have it set at quite low preload to avoid hard fast damping over bumps and potholes. Obviously your YSS will be different again. You can make a good estimate of the spring rate by measurement of the wire, O/D and no. of coils and using a calculator like http://www.reliablespring.co.uk/calculator.htm

[aesmith]

Cheers, one thing that puzzles me looking at those Racetech diagrams is that the SV forks don't seem to have that check valve at the bottom of the stanchions, unless maybe the top-out spring acts as a valve.

Quick bounce just now shows no overshoot on the front, in fact the rebound is a bit deader than in that video. Will need to check after a warm up ride.

[Bibio]

unless your dampers are dropping out the stanchion then the check valves are there. they are built into the bottom of the stanchion.

when doing the bounce test you need to put a LOT of force in one quick push.

[aesmith]

Originally Posted by Bibio

when doing the bounce test you need to put a LOT of force in one quick push.

Graphically illustrated here starting at 6:10 .. https://youtu.be/Ikjw4IheeF4