【YSS】Fork Upgrade Kit Review

It was new but contained used.

There are no performance problems with the product.
I'm glad I bought it
However, there was a slight lick mark on one side of the Initial Adjuster from turning it with a hex.
Obviously, it is used.
Was it for returned goods? View detail

Large changes until you can aim at Setting.

I used it on a CBR650F...Before Impression...although the stock information stated that I would receive it in a short period of time, when I placed the order, the delivery time was extended to several weeks and months, and in the end it took almost 3 months to receive it.
I understand that there are some reasons, such as the product does not sell well, or the distributor does not have it in stock because it is imported, but if it takes time, I wish they would have mentioned that it takes time.

Product Contents include Spring, ForkValve, Color, Top cap (with damping adjustment), Fork oil (small quantity) Quantity:The top cap alone costs about 10,000 yen,
Considering ForkValve 10,000 yen and Spring 10,000 yen, is this what the price is? I think it's about the same price.
In addition to the items shown in the picture (Preload Adjuster, Exclusive Collar, Exclusive Spring, PD Valve, PD Valve is the key of this product), Instruction Manual etc. and YSS Fork oil No. 20 are included. The capacity of this oil is not enough to replace the oil in the Single Body. I would like to see the price of this product lowered a little without including it.
In addition, the viscosity of YSS's Fork oil (40°C) is quite firm, at 99.4mm2.s.
For example, Honda's Fork oil No. 10 as OEM compliant is 34.7, so you can see how hard it is.
In fact, the kinematic viscosity of fork oil varies so widely from manufacturer to manufacturer that it is not uncommon to find that Company B's No. 10 is harder than Company A's No. 20.
I was worried about the hardness of YSS's fork oil because it was too different, and I also thought the fork oil itself was too expensive, so I prepared KYB's No. 15.
...Yeah, I didn't realize I made a mistake here.
When it came time to replace the oil, we realized that one bottle of KYB Fork oil was not enough, as it is 600ml. I ended up having to buy another bottle, which was expensive.
The fork oil comes with only 250ml as an adjustable amount, but of course it is not enough for a full change of 650F, and if you buy yss fork oil, 1 liter is enough.
If so, I'd like to see the price lowered without including this.

Dustcloth becomes pure black.
The valve should be loosened once to make sure it is firmly set to the specified value. 2 revolutions from the beginning of the pre-road engagement is the specified value.

Spring rate is 7.0-11.5N.
Considering that the OHLINS for 650F is 7.5 and the Scuder RearOkumura's MESUPER SPORTS750 is 8.3, the numbers are reasonable...?
It would be best if I knew the NORMAL Rate, but I couldn't find it there.
However, in NORMAL mode, the Front is too soft and moves in a nimble manner, while the Rear is too rigid and does not seem to move at all. (Of course, it does move slightly.)
Therefore, the direction is hard in the front and soft in the rear....

The PD Valve, depending on the model, may require an extra hole in the seat pipe to reduce the resistance on the compression side, but the kit for the 650F did not include such instructions, so I installed it as is.
The PD Valve has a Route, which is tensioned by Orifice + Spring that opens when pressure exceeds a certain level, on the retracted side, and a Shim with a weaker Spring on the extended side.
Since the seat pipe is unmodified, it basically means that the resistance is increased in the NORMAL oil path.
The weight of the resistance on the contraction is the Spring rate. The resistance on the extension side is auxiliary and can be seen as almost unchanged at about the Shim of the PDValve.

On the shrinking side, there is a small orifice that seems to pass through when resistance is weak, but when excessively large pressure is applied to it, the spring is pushed open and released from the center.
It's a way of increasing resistance in areas where it doesn't originally exist in NORMAL.
However, as far as I can see, the orifice has only one hole, and I wonder if this will cause the Spring side to open immediately if just a little resistance is applied...?
Maybe we can raise Spring's Tension...

I actually replaced it and ran it for a bit.

The front seems to have become a little harder due to the change in rate. I have an impression that the front has become a little stiffer due to the change in the rate.
After assembly, we headed out for a test run. We went to Hakone for a test run in the city and for a light winding.
At this point, the fluffy feeling felt by the OEM is gone.
I thought it looked good without bottoming out.

And the other day I ran about 440 km round trip.
I think the PD Valve thickness is offset by the Exclusive Collar........ I think it's either that or the PD Valve thickness is offset by the Exclusive Collar....
But if the Oil is too hard, it seems like the PD Valve shim will open up and flow...
In the meantime, I would like to see Timing and change the Fork oil to something softer.

This product is only Setting parts. It is not something that can be just popped on and done. It is not something that can be simply popped on.
I think since I took the time to decide on the Setting

I think it is not bad if you consider that the cosmetics are good and that there are more parts that can be set. View detail

We hope that GSX-R125User on the Circuit will find it useful!

It is supposed to be for GSX-R150, but I bought it for GSX-R125 because the distributor's website said it was for both 150 and 125. As a result, I was able to install it without any problem.
I also purchased this product as a Circuit Running and am satisfied with its perfect performance.
The installation process is a piece of cake if you have ever done a Fork oil change. Even if you have never done it before, you can do it if you have some tools. We recommend that you change the fork oil while doing the work.
The top cap of the fork is not screwed on like the FOR JAPAN MODEL production type, but only stopped by a C-ring using the force of the fork spring, so it requires a bit of hang, but as shown in the photo, it can be removed quite easily by using a Tie Down Belt and TWrench, etc. However, it can be easily detached by using a Tie Down Belt and TWrench as shown in the photo, or by preparing a 3-way Vise.
The Instruction Manual for the product is very unfriendly, but it seems to recommend an OilLevel of 125mm, so you will need about 200cc or less of Fork oil on the One Side when replacing. Also, although Fork Oil No. 30 is included in the package, it is not recommended to use Fork Oil No. 30. Use this with a Single Body. I don't think that's the case (it's only 250cc so it will run out after only One Side). I think the OEM No. 10 has enough viscosity, so you can mix No. 30 to your liking. View detail

At the same time as Overhaul

As I mentioned in my diary, the installation is done at the same time as the Fork Overhaul, which requires special tools and skills, and takes a lot of gold and time if you do it yourself.
But it works:unlike the OEM's bulky suspension, it has more waist and tracks better on the road.
The performance is quite high.
It would be nice to replace it while doing Overhaul. View detail

Worth the price.

Ninja250SL/The OEMFork of the Z250SL is not the most comfortable to ride on the street, as it is soft and has a thrust to it that comes back to you during cornering. Still, the light weight of the vehicle can be deceiving. "I think I'll leave it as OEM - I'll just add a Preload Adjuster..." However, I took the plunge and purchased the Upgrade Kit, partly because I had replaced the Rear suspension with YSS.

For installation, since the fork cap is a C-ring type, an SST with a portion of the clamp cut off is required, but anyone who can change the fork oil can install it themselves.

In case of PD ValveUnit Purchase, many models require orifice modification, but in case of Z250SL, for some reason, there is no description about orifice modification even in Instruction Manual. Large enough to have little or no damping.

Normally, it is necessary to cut the collar for the PD Valve, but the Upgrade Kit comes with a pre-cut collar, so this work is not necessary. It is a hassle to cut the collars horizontally, so it is good that you can install the collars by yourself as long as you can remove the fork caps.

The kit included 30W Fork oil, and the instructions were to put in 300ml each. However, reading some of my predecessors' blogs, etc., I found that some people were installing the kit with the OEM specified 10-15W and the specified amount (about 350ml), so I tried setting it with the latter for the time being. If I feel it bottoms out or is too soft, I will change it to 30W.

The first thing you'll notice when you install it is It's kind of softening." I thought it would be harder because of the Reinforcement Spring, but it was softer in the beginning, and the thrust when riding on the street was drastically reduced and the ride quality was improved.

I went touring with it and attacked the descent of a certain Tsubaki Pass quite seriously, but it held firm against sudden braking and did not bottom out, allowing me to attack with confidence. Even a high degree of freedom in line taking is now even freer. No one rides this Motorcycle and says it can't turn. Cornering has become so much easier that it seems to be.

I also drove Izusuka after that, and to begin with, Izusuka with 250 is not fun because even if you are always at full throttle, you are left behind by the litters, but even at high speed cornering, the front does not come back during cornering, so the line is perfectly set and very comfortable. Of course, since it is an SL, the line can be changed freely even from full bank, but anyway, the increased sense of ground contact of the front gives me a feeling of security.

Preload AdjusterSingle Body was about 10,000, so 35,000 is a good price considering it includes PD Valve and Reinforcement Spring. I think it is worth it. If you are not sure about the price, you will not regret installing it.

The only drawback is that the PD Valve damping adjustment can only be made by draining the Fork oil and removing the PD Valve under the Spring. Although this is unavoidable due to the system of retrofit damping adjustment, the C-ring type top cap is troublesome to remove and install, so I only do it when I change the fork oil, and I do not feel like removing the fork and adjusting it again just because it is a little different after driving.

If you change the front and rear suspension and put on high grip tires around α13-SP It's hard to fall over on a public road unless you're doing it on purpose. It will be a CorneringMachine that makes you feel like you are a part of the world. It makes touring fun because you have a sense of security that you can definitely turn, and you may think that you have become good at it, but be careful, because just because it is a motorcycle that anyone can turn does not mean that you have become good at it. View detail