Anyone fitted the YSS fork upgrade kit?

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k2apache6.0
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Re: Anyone fitted the YSS fork upgrade kit?

Post by k2apache6.0 »

Good observations there tomtom, especially the one on the damper rod and it's necessary modding with larger holes.
The 5mm shorter springs would explain somewhat how he is able to simply twist the threaded top caps on by hand in the video, the preload adjster could then be applied to 'take out the slack' as it were. The none threaded ones on mine required some downforce before the clip could be installed with the stock springs. If the YSS ones prove to be shorter I'll use a stack of washers or some aluminium pipe to right it. That pic confirms some PCX's had threaded top caps, I just wish bikerzbits did a better job of describing the product, and it's application/s than their (one liner) description job on the listing. Jeez, especially in view of those non-mechanically inclined's likelyhood of installing the PDD valves without modifying the damper rods first!
My PCX mod build here..
http://www.hondapcx.org/viewtopic.php?f=7&t=7113
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

Remember YSS PD Valves are copies of race tech emulators.
They, at least, have insight of what it is. See: http://www.racetech.com/page/title/Emul ... hey%20Work

What i see in the YSS video makes me highly suspicious:

1) they did not disable the damping rod by enlarging it (risk of cavitation) look at the link of racetech for explanation
2) they lower the amount of oil to 95 ml
3) they use a higher grade oil (20W)


The two first points do not make sense. The three combined are not likely to be optimum. This is very strange and goes against install intsructions of YSS themselves.
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Re: Anyone fitted the YSS fork upgrade kit?

Post by WW125EX2C »

Hi All,

I'm in the same process to upgrade my front fork riding and braking comfort.

Bad roads (Belgium) and noisy springs (when braking).

BTW I allready have Michelin City Grips, YSS G-Euro shocks and Brembo Oro brake disk and pads installed.

E-mail answer from Emmet:
Yes the YSS PCX Front Fork Caps should fit on your 2012 Honda PCX 125 eSP (JF28) o_O

Personally, I don't think so.

From what I've read, YSS 238mm PD valves, 15W fork oil (or should I use 20W ?) and stock springs, should give me a nice improvement.

YSS PD Manual says, I have to cut 14 - 17mm (thickness of PD valve) .....
Anyone done this?

Suggestions and advice are welcome ;)
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Re: Anyone fitted the YSS fork upgrade kit?

Post by k2apache6.0 »

Yes, a few of us have, but there's no need to 'cut' anything. The valves are short enough to only compress the springs ever so slightly, if anything its an slight improvement. The only modification you need to make is to the damper rods in each fork lower leg so you'll have to remove them via the allen bolt at the bottom of the legs. After that enlarge the existing holes to 14mm- (5/16") or thereabouts..The idea is to pass enough oil up to the PDD valves to do their job, the stock hole size is too small to accomplish this. Use a step drill if you have one with lands that are thick enough to create clean holes considering the radius and thickness of the steel f you have one, and de-burr after drilling on both sides of the holes before cleaning them up of drilling debris. I used 15w fork oil and can tell you its a big improvement in combo with the valves, especially over sharp edged bumps. The PDD valves need to be adjusted for your clothed weight, I used 2 turns in for 190-200lbs but 1, 1/2 might have been better in retrospect. Both Oyabun and another member who also had pictures did great write ups on the forum on this subject, search 'PDD valves' and take a look.
My PCX mod build here..
http://www.hondapcx.org/viewtopic.php?f=7&t=7113
tomtomclub2005
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

@WW125EX2C

See this thread: http://www.hondapcx.org/viewtopic.php?f=9&t=4877
There is a link to the YSS install guide (pdf) and tips and reports from several of us. No need to shorten your springs, (there is no spacer in pcx forks) the valve will add useful amount of preload by themselves-
Greetings from BXL
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Re: Anyone fitted the YSS fork upgrade kit?

Post by WW125EX2C »

k2apache6.0 & tomtomclub2005,

Thanks for the help.

Brooks Barn is out of stock, Wemoto shows a different PD valve picture (see: http://www.wemoto.com/parts/picture/ys-pd238/ ), specs are correct.

BTW How can I zero the valves and adjust 1.5 turns?
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Re: Anyone fitted the YSS fork upgrade kit?

Post by k2apache6.0 »

"BTW How can I zero the valves and adjust 1.5 turns?"

Hold nut with wrench and loosen allen screw until spring is free to turn. Now turn allen clockwise until spring just makes contact and stop, turn 1/4 turn to seat ..Now its 'zeroed'. Mark allen head with silver marker pen or other visible marking and using this mark as a guide (like a clock hand), turn allen clockwise 1.5 revolutions. Done.
My PCX mod build here..
http://www.hondapcx.org/viewtopic.php?f=7&t=7113
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

Wemoto is probably using a generic picture - don't worry as long as its a 238.
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Re: Anyone fitted the YSS fork upgrade kit?

Post by WW125EX2C »

tomtomclub2005 wrote: 3) they use a higher grade oil (20W)
YSS recommends 20W fork oil, see: http://yss-hamburg.de/media/files/YSS-F ... IST-01.pdf

I still don't know what fork oil and amount (188 or 122ml per side) to use.
15W or 20W as recommended by YSS ?

PDD valve order placed (Wemoto) and waiting for delivery ;)
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

Oyabun (who was the first to fit and report about PD Valves here) and I use 15W, 20W should be fine too. For oil level, i would stick with what is the PCX manual, not the YSS.
If you do not enlarge the holes in the damping rods you will have two damping systems competing one with another with unknown results, i cannot see the point of installing the valves in this case.
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

@k2apache6.0 did you receive your front springs? Any news?
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Re: Anyone fitted the YSS fork upgrade kit?

Post by k2apache6.0 »

tomtomclub2005 wrote:@k2apache6.0 did you receive your front springs? Any news?

Yes, sorry, been a little busy lately. The springs are fitted and I would estimate about a 20% increase in stiffness. At my bodyweight of about 185 pounds they are slightly on the firm side, but its helped the handling especially at higher speeds. I'll be doing an update along with some other mods on my thread shortly, and after I've had time to evaluate them fairly
My PCX mod build here..
http://www.hondapcx.org/viewtopic.php?f=7&t=7113
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Re: Anyone fitted the YSS fork upgrade kit?

Post by tomtomclub2005 »

There's now an "official" YSS installation video
Again, they don't enlarge the holes (!!) and those screw type end caps are nowhere to be found in europe.



and here is the pdf of the whole kit
https://www.yss.co.th/downloads/20170502074933.pdf

Notice how the spring is a straight one, not progressive in the drawing (:good)
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