Why robvangulik and xpd153 don't buy new motorcycles?

[xpd153]

The reasons are revealed in different thread.

Scotty Kilmer also said 'Why car guys don't buy new cars' at following video.

https://www.youtube.com/watch?v=YVAFnW46-Vw

[robvangulik]

 

[xpd153]

By the way, how many times did you change clutch slave cylinder piston seal of sc21 for 30 years? > robvangulik

 What thing triggered you decide to replace slave piston seal?

My latest vehicle, Aprilia Futura has hydraulic clutch. For me, it is first hydraulic clutch motorcycle. But many people have clutch problems with Aprilia/Brembo clutch. Like leaky slave cylinder, too heavy clutch lever, and Brembo seal supply problems.(Brembo did not sell rebuild kit via Aprilia channel.)

 My Futura has leaky piston seal problem at both cylinders. Currently it is working. But I have uneasy feeling.
 I am considering to replace Brembo master cylinder with Nissin. Because availability of Nissin is far much better than Brembo.

[robvangulik]

Be careful about piston size, as that affects the force necessary to apply the clutch. But go for the Nissin if possible!
I never changed the slave seal of any sc21 clutch, they never leaked and the only maintenance I did was to change the fluid every 3 or 4 years, not following any schedule, just when I thought it was getting too dark, which is usually an indication there is too much water accumulated in the system.

[robvangulik]

I looked in my service manual for the sizes, the slave piston is 35.7mm diameter, the master cylinder is 14mm, so you can compare those with your Aprilia ones.

[xpd153]

I have a replacement plan for only master. Futura and RSV1000 have 12mm at master and 28mm at slave.
Nissin has 1/2 inch,14mm and 5/8 inch for master. I will hunt 1/2inch used one.

Brembo slave cylinder has different mounting bolt positions. Therefore,replacing it with Nissin is difficult.

Usual Brembo slave cylinder is like this.

https://www.makewoodgood.com/wp-content/uploads/2019/08/refit-cylinder-to-bike.jpg

And I think replacing fluid in Brembo slave cylinder by ordinary bleeding method is difficult.
Because bleeder valve and fluid intake are sitting on same bleeder plug. And the cylinder is dead end.

I checked shape of SC21 slave cylinder.  Bleeder valve and fluid intake have each own position.
https://www.picclickimg.com/d/l400/pict/173374873380_/Honda-CBR1000F-CBR1000-SC21-Clutch-Slave-Cylinder.jpg

Even today, Brembo slave cylinder shape is not changed. But I like Nissin shape.

[robvangulik]

Replacing the Brembo with a Nissin slave would indeed be difficult.
But giving the Brembo a separate bleeder shouldn't be too hard, drilling a hole and tapping a thread in an easy to reach place....and then you can use a normal banjo bolt for the fluid intake.

[xpd153]

Your SC21 is 30-32 years old and run over 300,000km. Still using factory set piston seal is far beyond expectation.
How about your brake master cylinder piston seal?

Aprilia Rotax V990 engine has hydraulic clutch. And as I said, many people have problems with their clutch.
Newer Aprilia V4 engine went back to wire clutch. Probably Aprilia also recognized hydraulic clutch problems.

At Honda, basically all over 800cc engines have hydraulic clutch. But I did not hear such problems.

[robvangulik]

Like I wrote, regular clutch fluid change is all I do on that side, I run a 1/2 inch brake master cylinder on all bikes, instead of the 5/8 normal on a sc21, and I always have new rubber o-rings in stock for service on calipers and master brake cylinders. Since owning also a sc24 I had to increase the number of 27mm rings, as the 21 only has those in the rear brake, and 30mm front, but the 24 all round...
I always try to save money, but survival is more important, I'll never save on brakes and tyres!