Installing YSS emulators on Curvy

[JaxintheUK]

I've just got around to sorting out my front forks and installing emulators. I bought 33.5mm YSS emulators and they don't fit well into the cup of the damper rod...just the tip of the seat fits. I was wondering if I could put an O ring around the emulator to create a good seal so it does it's job properly. Will it last in that environment, will it be a good fix? Not going to drill the damper rod unless I know that it'll work.

[johnnyrod]

https://www.svrider.com/forum/showthread.php?t=394375
Hmm. And don't drill the damper rods, at all, if they work the same way as the Racetech ones - I don't know why they put that in the instructions. Okay to clarify, Racetech say to drill out the last damping hole, all this does is ruin the rebound damping at full compression, do YSS say to do the same?

[JaxintheUK]

You have to drill out the damper rod holes to bypass the damping effect, the emulators take the place of the holes in the damper. I want them to work properly and seal at the end.

[johnnyrod]

Sounds like from the link I posted that they don't really fit properly. I have the Racetech ones and they drop straight onto the damper rod tops and fit fine (FWIW). For them, they only control the comp damping and leaves the rebound to the damper rods, but they have since revised their instructions and taken out the drilling part. If you do the drilling then you just make a mess of the rebound, which the cartridge doesn't affect anyway - it has a large one-way valve to stop it causing any rebound damping.

Just a thought, I don't know much about the YSS ones, but from googling they look awfully similar. You did read the link above, that they don't necessarily fit gen 1 SVs?

[glang]

We seem to be getting mixed up here as according to the Racetec info here:

https://racetech.com/page/title/Emulators-How%20They%20Work

the compression holes at the bottom should be increased to allow the emulator to take control of this damping then rebound is controlled, as previously, by the top small hole. With an emulator fitted if you want to change rebound some people recommend closing the top hole (the fork check valves leak so much that theres still enough oil flow) or using a thicker oil. This latter option will obviously also affect compression but can be adjusted for with the emulator.
The emulator should fit well in the top of the damper rod so that it cant move around too much but its not necessary for it to have a seal as the main flow of oil will still go through the emulator....

[garynortheast]

Have a look at this thread (http://forums.sv650.org/showthread.php?t=177012&highlight=Debrix+emulators). It deals with the Debrix emulators a lot of us fitted 7 or 8 years back but they work the same way.

You need to open up the compression damping hole and seal up the rebound hole. Welding of the rebound hole was originally recommended; however I used JB Weld and 7 years later it's still firmly in place.

[aesmith]

I fitted the YSS 33.5mm valves to my pointy. That makes me think they're the wrong size for a curvy as from memory didn't the Debrix fit straight into a curvy but needed a bushing for the pointy?

[JaxintheUK]

I wasn't talking about the small rebound hole at the top of the damper, just the 4 main holes that need drilling out to 10 or 11mm.



Thanks Glang, I wasn't sure if the emu had to sit in the cup firmly. I want to use a rubber O ring to ensure stability as only the top of the emu fits into the cup, it will be held down with the spring and spacer anyway.


They are definitely the wrong size base for the K1 curvy, but with a bit of help and bodging, hopefully they'll work.

[glang]

I think o rings will get mashed pretty quickly as theyll have to take the full spring force when hitting bumps and things, or will the o rings just be to keep the emulators centred (you deffo dont want them to move while riding)?
Also will you be making any changes to the rebound holes as Im preparing to do mine and thinking of tapping them to fit screws?

[JaxintheUK]

Just to keep them centered, don't want them slipping sideways. I'm going to experiment with the rebound hole...I'll leave it alone and see what it feels like, if I don't like it I'll put some steelmate in it, that's what others have done. A bit nervous about drilling the damper if if's not gonna work properly...don't want to have to buy more shocks if I mess it up.

[glang]

You could install the emulators without modifying anything (more work I know) but then at least see the difference you get under braking. You should find noticeably less dive....

[Adam Ef]

I did my pointy forks with the YSS emulators. They seated perfectly on the top of the damper rods. You do need to weld up the very small rebound holes and drill out the higher ones to be wider (10 / 11mm?) other wise the holes will be only allowing a certain amount of oil through and the compression setting on the emulators will have no effect as not enough oil is reaching them quick enough for them to take over controlling the oil flow for compression.


With the rebound hole sealed up you adjust your rebound by experimenting with oil weight. Then once you have that worked out you set the compression on the emulators with that weight oil . It's all a bit of a messy process and takes time but works in the end. I redid mine 3 times before being really happy with them.


I remember reading a thread a while back about someone who got something machined to adapt the top of the damper rods on a pointy to allow the YSS emulators to sit neatly. Sort of like a cup adaptor that sat inbetween the two.





+ If you think all the drilling and welding is wrong you don't need to replace the whole fork, just get different damper rods. I doubt you'll find that it is wrong though. Mine was a huge improvement.

[garynortheast]

I fitted the YSS 33.5mm valves to my pointy. That makes me think they're the wrong size for a curvy as from memory didn't the Debrix fit straight into a curvy but needed a bushing for the pointy?

Yep.

[JaxintheUK]

So frustrating, I read as much as I could on doing the emus and I'm a bit reticent about putting these ones in now . Will the O-ring give it stability? It's pretty much perching on the edge of the damper cup. Will it work? I don't want it slipping around inside the fork and fouling anything. I have to go to work tomorrow afternoon, so I'll probably put it back together sans emulators for the moment.

[Adam Ef]

I'd get something machined. I wouldn't trust o-rings to keep it in place and you don't want it moving at all as it will either let all the oil past, or none at all and lock up your forks. I wouldn't enjoy riding a bike looking out for that happening all the time.

[JaxintheUK]

I fear that you're right Adam. Oh well, I needed to do the fork seals anyway.

[Adam Ef]

New springs and heavier fork oil will improve things on their own too. Try it with the rest left stock?

[johnnyrod]

The stock springs are rubbish so that is the best thing to change, but I found the (Racetech) emulators give the front a great deal more subtlety. Don't expect more stiffness, that's not the point, but things like tarmac ripples are dealt with much better.

[JaxintheUK]

I put in 10w oil and it felt lovely and firm, but the damping was horrible...any small bumps I could feel more acutely. I'm going to mix into 7.5w and see what it feels like. I don't want it to feel like a gixxer! lol

[johnnyrod]

How have you set the preload of the centre spring on the emulator?

[glang]

Dont think Jax fitted the emus in the end as they need some sort of spacers making up to seat properly.....

[JaxintheUK]

Not installed. I might make a little shim thing up to stabilize it...not gonna buy another. I'll fit a tube within a tube to get it to fit...as long as it doesn't get in the way of the emu damping, it should be alright. hmmmm [-o<

[glang]

How did you end up with the wrong ones Jax? I see the Wemoto part number is very similar for curvy and pointy...

[JaxintheUK]

I read that the 33.5 one were for the SV and heard it mentioned a number of times in various threads. I have a habit of being an idiot sometimes! lol I didn't even realise that the ends might be different. It's pretty daunting when trying something new and not having much of a clue, even though I did read up on it...just not enough I reckon.

[glang]

yeh we've all done it! No chance the company will swop em? Postage wont be expensive and its got to be less hassle than spacers.....

[JaxintheUK]

I could sell these and buy the right fitting ones. Any idea if the 31mm ones fit?
Outer Diameter 31mm
Diameter for piston bore in the fork: 24mm
Height valve total: 16mm

[glang]

cant confirm it directly but using the Race Tec site which has more info, their emulator FEGV S3801 (31mm/25mm/16mm) fits Curvy SV650, VS1400, GS500 etc and that corresponds to the same models using the YSS PD310 emulator....

[garynortheast]

Have a quick look at this thread (http://forums.sv650.org/showthread.php?t=202239&highlight=Debrix+emulators). The Debrix link doesn't work now but the info you need is contained in the url and in the thread regarding spacers.

[glang]

Dont know if that helps as we dont know how the YSS and Debrix items compare. Hopefully the YSS items are specifically for the curvy so no need for spacers to seat them on the dampers rods....

[JaxintheUK]

It's a damn shame I wasn't part of this group when the Debrix emus were around. Oh well, at least I know a lot more about fork internals and damping than ever before...not a bad lesson eh? I'll sell these and buy the 31's. Thanks for the help y'all :)

[Adam Ef]

Someone wil have them on eBay I'm sure. They fit quite a few bikes.

[Bibio]

my advice for what its worth.. dont bother with emulators unless you want to spend a fair amount of time ****ing about getting the "pop" right.

1. get the proper springs.
2. weld the rebound holes up.
3. use silkolene RSF10w.
4. ride it like you stole it.

its that fukin simple.

[JaxintheUK]

Yep, I'm starting to think getting new springs is the way to go. 10w oil feels so much better and stiffer than 7.5, just a bit bumpier. Closing up the rebound holes without emus? What will that do to the suspension? Won't it feel a bit juddery? Why are they there? Still learning about suspension setups, so please excuse all my questions. :rolleyes:

[aesmith]

New suitable springs should be the starting point. If you don't have access to a welder you can block the rebound holes with epoxy. On that point I understand that the SV rebound is mainly "controlled" by leakage between the fork tube and the damper rod, where it says "Check valve passage" in this diagram https://racetech.com/HTML_FILES/DampingRodForks.HTML

[Adam Ef]

Yep. Most of the fluid leaks through where it's not meant to rather than the rebound holes. Weld them up to get it under control a bit more. Springs for your weight and oil for the compression speed that you want. Air gap can make quite a difference to plushness too.


I did the emulators and I think it took me about four or five times messing with oil and removing them and adusting them before I got near what I was really happy with. That process lasted a couple of months. I'd say most of the effect came from the new springs and oil though.

[aesmith]

I did the emulators and I think it took me about four or five times messing with oil and removing them and adusting them before I got near what I was really happy with. That process lasted a couple of months. I'd say most of the effect came from the new springs and oil though.
Out of interest what was you're process for tuning the emulators? I mean for deciding which way to adjust them. I'm not sure whether to start with them fully backed off then increase the preload until it reduces dive on the brakes. Or go the other way, start with them cranked right up then if that's too harsh try them a little softer. I'm currently on two turns of preload by the way.

[Adam Ef]

I think I read a guide somewhere that said they recommend 2 and half turns in as a good starting point. It took me a while to work out where that started from though. With them turned all the way out or just taking up the slack so that the bolts are just starting to move the discs? I think I went with the latter and found them slightly harsh. But I was mixing different oil in each time I did it. I think in the end I ended up with equivalent of 12.5wt, which is starting to get heavy (esp with the Silkolene RSF I used as that it quite a heavy one anyway .. no two brands are the same no matter what number they put on the bottle). The heavier oil would have been affecting the emulators a bit so I think I ended up with them 1.5 turns in and that weight of oil gave me good controlled rebound too. No pogoing when the suspension bounced back up.


The guy I sold my bike too was blissfully unaware of what I was talking about when I told him I'd done all this. He probably thinks that SVs handle like mine did as standard. I put weeks of work into it though. I did enjoy it though, sort of..

[johnnyrod]

The number of turns is from when the springs are just seated. They are quite soft springs so you have to pay attention to finding that point otherwise you'll end up with the two emus set differently.