Has anyone here managed to make a Blackbird (or any Hydraulic Clutch) a bit more civilised in a BEC? My clutch pedal (more of a switch really) has about 1" of travel and absolutely no resistance whatsoever (although I've improved this a bit with an arrangement of heavy springs).

I'm guessing I just need to change the master cylinder for one with a smaller bore, but If anyone's already been down this route I would appreciate any advice...

Can you move the fulcrom pin up the pedal so the ratio of the lever to actuator is greater? i.e. so you move the lever further per mm of movement in the cylinder.

oh dont get me started on the clutch ...

its like a hyper space button not a clutch

try i master cylinder with a smaller bore i think i have a gsxr 1000 one on mine its still like a button though..

also be carefull to make sure you put a stop on the pedal so when u press the clutch it dosnt move to far mal at yorkshire engines told me the consiqueses are not desirable if this is not done

put the car on the ground in gear then have someone push it and slowly press the clutch till the car begins to move then set a stop behind the pedal.

out of curiosity are you using the origonal shave cylinder iff you are how have you got the prop mounted to the adapter without it hitting the slave cylinder or are you using chain drive?

just noticed you have a fury so its not chain drive..... should really check these things before i open my mouth


so yes out of intrest how have you got round the front UJ on the prop hitting the slave?

tilly

I have used the Westfield arrangement.

It is a gantry with a bike rear brake master cylinder so it is a small piston size.

Can adjust the ratio at the pedel too with holes at different hights from the pivot.

http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=GT-1 Master Cylinders.JPG

Have a look at the above pic in my photo archive to see what I mean. (don't know how to make it come up in the post)

Clutch is still a little sensitive, but very good once used to it.

Cheers

Mike

[Edited on 7/3/10 by Mike S]

Right I have an R1 engine and I have a long pedal.
It doesnt matter what slave you use but as long as when you push the pedal to the floor the slave travels the full extent that it was designed to.
From there you will need to extend your clutch lever to operate the clutch over a longer arc.
Remember to remove any freeplay from this arc. Freeplay is there to allow your hand to gain some mechanical advantage when you pull the hand clutch in. It's not needed when you are using the power of your leg.
My set up uses a wilwood master and wilwood pull slave.
I worked mine out by measuring and transfering the dimensions to paper. Using a compass I drew an arc and worked out where the best place to attach the slave based on the slave cylinder travel. In my case 34mm was the slave full travel.

Before modification:


clutch lever 2

After modification


Description

Description

You will be amazed at how much like a car clutch mine is, not an on off switch with a bolt to stop you pushing the clutch pedal to far


[Edited on 7/3/2010 by nitram38]

You do need a little free play in a hydro system, to ensure the master piston fully retracts and uncovers the hole which allows fluid to leave and enter the cylinder from the reservoir. The 1st and slight movement of the piston covers this hole, before pushing the fluid through to the slave.

I'm talking about the freeplay in the clutch lever arm, not in the slave cylinder. Not removing the freeplay will cause you to waste part of the slave travel and may make your bite point too high up your pedal. Mine is half way on my foot pedal

Not sure about blackbird, but I have a hydraulic clutch on my GSXR1100.

I have used a Kawasaki slave cylinder, and the rear brake master cylinder from a sv650 (although lots of bikes use the same 1/2 inch diameter version).

It has a decent amount of travel and the SVA tester could deal with it in his heavy boots.

Be aware that if you change the ratio so that you get more travel, then you automatically get LESS pedal pressure. It is just a mechanical advantage thing. To add resistance at the pedal end you would need an additional spring. I haven't got one, but I should add one.


Matt

On my blackbird, i have spaced the std honda slave cylinder off of the engine case using studding and alloy tube this gives enough space for the sprocket adapter and the rubber cush drive.

Just using a std willwood mastercylinder at the mo, have a light pedal also but i'll sick with it unless it bothers me.

This is how I got around the problem on the GSXR1100 engine, i'm guessing the blackbird has a similar setup:

quote:

---

Originally posted by tilly819
just noticed you have a fury so its not chain drive..... should really check these things before i open my mouth


so yes out of intrest how have you got round the front UJ on the prop hitting the slave?

It's extremely close!!! The whole assembly is spaced away from the gearbox by about 2cms. Seems to be fine, but as I say it is very close (the sort of this I'd rather not think about while I'm driving it)

tilly

---