Monthly Archives: April 2016

SR 400, 500 dry clutch,to trial run to Nanamagari.

I set a dry type clutch plate, tried running until the road station Mitsu. There is Nanamagari pass near this,The place is touring or drive spot.

It is a distance of 50 km one way from my house and 100 km by round trip.I ate the soft cream at the road station Mitsu,Because it was lunch time on the way home,I ate a hamburger at Route 65.So, the total mileage for this day is about 140 km.

I reduced the number of sheets as the thickness per clutch plate increased.It did not slip and it was OK.Friction Capacity is OK.This SR is 500, so if it is 400 it will be OK further.
That’s great dry type. The clutch is crisp is good, so the mission soon entered.
This was very comfortable.
Wet type has no problems in practical use,Because of the oil film intervening ,It was a little dragging.
Although the clutch did not slip this time,More and more the play  increase,It is reaching the point where the clutch can not be disconnected.
It turned off the clutch, but it became a state that it could not be completely cut.
It is hard to enter neutral while waiting for a signal.
Perhaps because the cause was not hardening the head of the release poppet,I think that  it has been  sharpen.

↓ This is normal.With this,the float the pressure  plate,It is turn off the clutch.

Looking at the color,only the head is hardening.

Although it is hardening,but as I ran distance, the head will dent accordingly.

I seemed to have to harden the head of the release, so I ordered the material of SKS 3 which can be flame hardening.
I roast it with acetylene burner and drop it in oil and hardening it.I will apply the file and check the hardness.

Consideration of SR400 dry clutch clutch plate

For now, I was able to SR500 to dry clutch. I was able to run.
I exhibited it to the Osaka Motorcycle Show.
And then, I was riding around remains of steeped of ordinary oil wet disk.
Clutch basket and clutch boss of the dry clutch is made of our Araki  Funkey Machine. This is an additional pyrotechnic of SR400.


After a while, it began to slide no longer off the clutch of SR500. I saw the clutch plate. It was warped. Distance traveled about 50km.
This is a good data.
This data would not listed also looking for the net.
If you are reading this
“What happens if I use a wet disk dry?”
When asked to someone and,
You are should I replied.
“You are beginning normally can run. But it can not be run only about 50 kilometers. When the running any more, things will get to come to pick a track to your father.”

If this is warped, to clutch slip, it should not expired.
By the way, it is called the side of the iron plate only the clutch plate (here ↑).
Then, the side that is put the friction material is called a friction disk.
So, I learned that I needed dry discs.
I tried disassembling the cover of 3XV TZR and looked at the clutch plate. That is what I had in our factory.


It is slightly smaller than SR. And the clutch spring is five. I look it up in “parts search of Yamaha“. It was a waste number.
Next, I examined the clutch of TZR250SP of 3MA in the parts search of Yamaha.
Clutch spring is the same as the SR in six.
Friction plate for about 1000 yen SR (360-16325-00),
3MA (3MA-16331-20) is 2700 yen.Expensive.
But, I bought.
Clutch plate came as for 3MA is the part number had changed. It had changed in 3AK-16321-00.


This is good.
At the same time, the clutch plate also for 3MA (3J2-16324-00) I bought. This is also perfect.
I had been hooked a while ago, that there is a law for Yamaha’s genuine part number.
I investigated further using it.
Yamaha uses the first three letters as the model number.
For example, in the case of TZR250 is 3MA and 3XV,
In the case of SR is 2J2 and 2H6 and 3HT,
In the case of TZM50 is 4KJ.

Then, what is 3AK?
It’s TZ250 of the 80s!
Until the latest TZ250,Is the same as the friction plate and this 3MA.
To the very old 3MA of TZR and TZ250 common parts of the clutch, but the fact that 3XV and TZ250 parts does not fit anything.
And, there was further discovered in the clutch of the TZ250.


Of the innermost and outermost of the friction plate, part number is different from the other.3YL-16321-01.

I bought it. This.
Maybe,Place in contact with the aluminum is, will the things that use this friction material.
The price is a little cheaper than 3AK-1632-00.


Dry friction disk is different at all wet and material.It is close to the friction material of the brake pads.Glass or Kevlar like a thing or metalic pubic hair like a thing is kneaded.And stench.It smells like Bakelite, or ramen soup.
In contrast, wet disc is made up of something like cork.I tried rubbing the clutch plate and the friction disk under conditions in which there is the oil film.It is, it feels like when chewed the pickles of eggplant.


I tried to measure the thickness.This data is the data that I took spend the time and money.But, to publish so I think there is a value.When I compared them, dry  disk is considerably thick.


Part number  thickness
Clutch plate 168-16324-00 2.3
Clutch plate 3J2-16324-00 2.0
Friction plate 3YL-16321-01 3.0
Friction plate 3AK-16321-00 3.0


name Part number thickness
Clutch plate 360-16325-00 1.17
Friction plate 5Y1-16321-00 2.8

I was ordered to reduce the number than the disk of normal SR.When you buy a number of disks required,It exceeds 20,000 yen.
For now (March 2016) is, all parts from Yamaha you can get.
If, when the supply of parts’ve finished,looking for a place  to sell the adhesive and the tape of the friction material,It will want to manufacture in my company.
Demand of repapering of the clutch of four-wheel is a certain number.So,to try to negotiate a company that is doing such a business  seems that good.Companies that are delivered to manufacturers, I think is probably rejected.

And I tried teamed up to the vehicle body.It was able to run normally.
Next, let’s ride in this specification.
It is completed if there is no  leakage of failure or oil of the clutch plate relationship with this.


By the way, The friction disc which ran 50 kilometers was reduced by 0.1 – 0.2 mm per one.
As a whole, it has decreased by about 1 mm.That clutch should slip.
I measured the friction disc of the SR 500 that ran many times and it was not decreasing at all.The thickness remains 2.8 mm.This is wonderful.The wet clutch is quite excellent.
Until now I have said that “wet clutch is mixed with engine oil and clutch waste”.But,This is not mixed at all.It has not decreased.