Topic: Master Cylinder Piston Sizes

[spiritof67]

First, does anyone have a spec on what the m/cyl piston sizes are for 1970-74 CB750's?

Second, what standard looking m/cyl is generally used for street use/double front disc setups? I always used my standard m/cyl - but I heard that a similar Kawasaki one was actually a better fit for street use.

Third, will an 11mm piston Magura m/cyl work OK for a street use/double disc setup?

Thanks to all, and bless the anoraks!

[scottly]

The stock MC piston size is 14mm for all year 750s.
The stock MC works well with '76 and earlier 38mm dual calipers, but starts to get a bit of a soft feel with 77/78 42.8mm calipers for some folks.
An 11 mm piston would be too small, unless it had 150% more travel than the stock piston.

[Djfob]

Piston size is actually stamped underneath m/c

[spiritof67]

Thank you. Have a nice Magura 11mm m/cyl and no bike to use it on. I used stock m/cyl on many double disc CB750's (we really didn't have any alternative in 1971...) but was unsure re: piston size. It was always my understanding that Z1 Kawas had a 15-16 mm piston m/cyl but I never saw proof of that.