Emulator spring preload changes

cbertozz

cbertozz

Hero member
Location
Australia
Righty-ho, one simple change: reduced the spring preload on the gold valve emulators. (Not in fork spring)

Now the bike feels a little harsh and like the head wants to shake over rough surfaces.

I was expecting it to feel less harsh.

The spring controls the compression circuit, and I had assumed that less preload would mean the valve would open more/quicker under compression therefore making the first compression softer.

Currently using the heaviest (red) spring so might switch and try yellow spring but anyone (apart from Vince  :LOL:) have a view?
 
Vince?s 300 page thread on the topic covers it in depth  :D
In my road SF2 I was supplied with the yellow spring and at the 3 turns preload it came with I had an inch of travel on the shit roads here. I swapped to the softer blue spring and it won about half an inch travel. I backed off preload to zero just to see, and I got back my full travel - so it wasn't stiction or such, and the bike was a million percent better. I put in 1 1/2 preload on that spring and it is as good as I want it for the bigger bumps, note I find it hard to determine just when zero is and to start counting turns of preload. Being so happy with that I decided to play a bit more and as it hasn't been supple enough on the small type of bumps, I now drilled an extra bypass hole for the low speed - used 2.5mm instead the unobtainable here 7/64" (2.75mm) so now it has two holes but as it is alternating between sleet, snow and freezing rain here now I cannot test it but it is a very small change. These units don't have the piston ring and I use 10wt fork oil in it.
By contrast the units I got for my race SF2 came with blue springs and I just put them in, haven't adjusted a thing, and they have been great. It seems to vary greatly between different forks. A fellow competitor on a ?70s BMW running Cerianis said he gave up on them and chucked them in the bin.
I see from your other post that you have just swapped out your rear units. Be aware that front end problems are very often caused by the rear end transferring forces to the front.
 
What weight are you, how heavy is the bike?

I?ve got the yellow spring in now but with 4 turns of preload, might try with less when I?ve had a chance to ride properly. Might try taking out 3 turns

I?ll have to ride a bit more but my arm is still bolloxed so that interferes with feeling.
 
cbertozz said:
What weight are you, how heavy is the bike?

I?ve got the yellow spring in now but with 4 turns of preload, might try with less when I?ve had a chance to ride properly. Might try taking out 3 turns

I?ll have to ride a bit more but my arm is still bolloxed so that interferes with feeling.
Click to expand...
A pretty well stock SF2, a bit over 200kg I would think. Fork springs are 0.95 from Racetech and with about an inch of preload (only have to compress a few mm to get the fork cap thread to take) sag is correct. I only weigh 66kg without riding gear, but the setup has been fine with heavier people riding it.
 
Tippie, zip tie on left fork leg - how does that look for normal form travel on a fairly spirited riding road?

IMG_2628.JPG
 
"Tippie, zip tie on left fork leg - how does that look for normal form travel on a fairly spirited riding road? "
It looks ok, but that is a subjective way to check it, if you had hit a sharp bump or braked really heavily, that would give the max travel. Static sag both with and without rider are really easy to check and then you can tune in compression damping etc.
Before I backed off my emulator preload that cable tie was less than an inch above the slider even with correct sag figures.
 
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