K3 front end

[garynortheast]

Any progress on this now?

[Fazer Fail]

Hi all, sorry things took a lot longer than i expected and issues with his other bike diverted my attention.

So used a big syringe and took out 300ml of the Silkoline 15W and refilled with 305ml (estimated would have lost at least 5mm in the process) of the Silkoline 5W, by rough calculations makes the oil a slight bit thicker than 7.5W bit short of 10W.

Effect is night and day! full movement back on the forks, low speed damping feels good, if a little soft for my taste but spot on for my son who is much lighter than me.

I was genuinely surprised how thick the 15W was and the massive effect it had.

In summary low speed is compliant comfortable, but biggest difference is how much tighter it feels almost no dive when breaking very stable, but deals with high and medium speed compression well you feel it still but not jolted out the saddle just soaks it up but lets you know was there.

I have no fears of bottoming out the heavier springs are working well and I think they will prevent bottoming out along with better compression damping time will tell.

It exposed how soft the back was but as its an sv1000 shock just dialed up the compression and balanced the feel front and rear.

Rebound feels ok nice and quick but not bouncing I imagine as the oil heats up this might increase so something to keep an eye on.

Will need more testing but the 0.9 linear springs and YSS emulators and decent fork oil have transformed it no end, his mate who rides a 929 Fire blade felt it was softer but very close to his for feel and comfort.

I am very impressed so far for this application here is summary of what I have done

Welded up rebound holes on damper rods
Enlarged compression holes on damper rods
Drilled 2 extra compression holes in damper rod (given better advice would NOT do this)
Replaced springs with 0.9 linear from race tech
Fitted YSS PD 335 set at 2.5 turns out
Silkoline Fork oil mixed to suit (suggest 7.5W as start point)
Set fork tubes flush with top yoke (actual tube cap soits slightly proud)

Can i just say a huge thanks to all who contributed to this and helped out, really appreciate it big time!

Still need to dial this in fully set the bike uo for him but a couple of jobs to do before then.

[glang]

Brilliant! just a couple of questions: what does son weigh? And has it cured the famous SV front suspension clonk?

[Fazer Fail]

Sorry for the delay he is about 70kg with his gear.

Did not feel or hear any clonks all seemed well.

Early days lots of final set up and tuning when he gets his license this has just been a slow build

[embee]

Sorry I'm late to this thread.
You've had good advice as usual on this thread.
I have spent quite a lot of time playing with emulators (Debrix), not Racetech or YSS but essentially the same basic design .
Anyway, to sum up my experience .....

The oil chart by Peter Verdone is invaluable https://www.peterverdone.com/suspension-fluids/

As others have said, and looks like you've already discovered, different brands and versions of oil have quite different properties regarding viscosity and temperature variation. I've been using the Fuchs/Silkolene "Maintain" oils for years now (used to be called Pro RSF, this is what's shown in the table). I find it lasts quite well and is consistent, plus the steps in viscosity are nicely spaced to vary your forks.

My experience is that the holes in the valve disc are critical to get the right feel on the road (track micht be different). I've found that trying to aim at basically the same hole area as was in the original damper rods is a good start, they usually come with pretty small holes, for example IIRC the Debrix came with 2 holes at 2.5mm dia, the original damper rods in my Honda were 2x4.5mm dia. I've ended up with 4x3.1mm holes which is very close to the area of 2x4.5mm.

The disc valve springs seem to be way too stiff IME. Again possibly fine for track use but too harsh for typical roads. I sourced some significantly lower rate springs and made some spacers to centralise the spring on the adjuster bolt. I also made the spacers such that they limit the travel of the disc (approx 2mm lift), my thinking being I didn't want the compression damping disappearing too much on harsh bumps. For example I think the springs I have in there now are 26 lb/in (4.6N/m), I'm not sure what the original springs were but it was of the order of double this rate (around 45 lb/in or 8 N/mm ballpark I think). Obviously the rate and the preload work hand in hand, but I found with the stiff valve springs I needed to drop the preload to a very low value in order to reduce the harshness enough, but with the lower rate the valve can lift more easily after cracking open so the preload isn't quite as critical.

Getting emulators right (for you) is unfortunately a case of experiment and adjust, as you have already discovered. It does require an understanding of what the various parameters do, the hole size, the valve preload and the valve spring rate, plus of course the oil viscosity. The actual fork spring rate is the easiest thing, it's basically what holds the bike up and determines the travel (under braking/bumps/undulations etc)

[Bibio]

Glad you got it sorted. If you want it a little firmer just do what you have done but take 50ml out and add 50ml 15w back in. There are also things like air gap you can mess with but in reality it doesn't effect damper rod forks as much.

[Fazer Fail]

Hi all great feedback for my son he says it's perfect as he is lighter than me. The bike feels planted combination of rear linkage being replaced an sv1000 rear shock with the OEM 1000 spring feels about right for the 0.9 spring in the forks.

From here it's going to be gradual tweaking when he uses it more.

I did my research on oils that why I went with silkolone they seem to offer less drop off when temperature increases hence more consistent.

I'm genuinely surprised and will not think twice about fitting emulators again just start with a very thin oil and work up until find what works.

Regards the bleed holes on the emulator that YSS only has 1 small bleed hole part drilled for up to 4 but for me at least using the thinner oil fixed this if I opened up any more holes I would need thicker oil and that would upset the rebound.
Plus for consistent result and less temperature effect looks like thinner oil is the best option.

One thing ticked off the list still to figure out how to attach these Tokico 4 pots that he wants and need to replace the Speedo magnet the lugs disinterested!

[glang]

I suppose the acid test is that the emulator valves must never open on the hardest possible braking the bike can be subject to? Not too demanding with the standard brakes but those 4 pots might mean the valve springs have to be tweeked....

[Fazer Fail]

Yes good point but tbh the speed of compression should be the key unless you make an unholy grab then it should be slower speed still a lot of force yes but the springs should help resist the dive.

Still very much a learning curve but at 2.5 turns the are set slightly harder but scope to increase just finding the balance so composure is retained.

Part of the learning curve I guess