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View Full Version : m/c hydro clutch to pedal hydro clutch ?????



bajaBrothers
06-14-2007, 09:08 PM
Hello all
we are finally getting some work done on our cars we should be updateing our log shortly.
soo.. I am starting to work on the pedal assembly and a couple of questions came up.
What size master cylinder should I use to convert the hand operated hydro clutch to a foot pedal operated one?
I have a set of wilwood pedals that are really nice but I screwed up and ordered forward swing pedals. The area where the clutch master cylinder goes is getting alittle close to some body panels but I think I can swing it (get it) [smilie=mhihi.gif]
I have seen some master cylinders that are shorter that others, is this an option?
Also is there anything else that should be done to make the bikes slave cylinder work properly with this new master?
Thanks a bunch.
-O
________
Mexico City Hotels (http://mexicocityhotel.info)

greasemnky
06-14-2007, 09:18 PM
I actually just converted a set of forward wilwood pedals to reverse pedals. I happen to have a wilwood reverse pedal in the garage, its the same pedal as the forward swing! Only diffrence, they bolt a little tab on top of the pedal to "push" the master. You can do the same thing, just weld a tab to the top of the pedal. Flip the bracket over (you have to cut a slot for the pedal to swing) and you have reverse pedals for 1/2 the price! I'll never buy another reverse pedal. Look close at the photos, the reverse pedal I'm showing is from Wilwood, its the same pedal as the forward swing! They modified it the same way I did my other pedals.

I'm running 3/4 master cylinders on mine, and it should be more than enough. I think 7/8 would be too large. If you look at a m/c *master, its really not that large.

Hope that helps.

busasandrail
06-15-2007, 10:03 AM
I use a 3/4 dia cylinders on mine and the only problem that came up was the foot pedal was overdriving the clutch slave cylinder. The clutch slave cylinder on a busa only needs about 3 mm of travel to disengage the clutch, with the foot pedal it was getting double that. All I had to to was build a stop for the pedal that limited it travel to what the cylinder needed.

masterfabr
06-15-2007, 11:22 AM
5/8" BORE WORKS BEST.JUST ONE QUESTION THO ABOUT YOUR MODIFICATION TO THE PEDAL .IT SEEMS TO BE QUITE A BIT DIFFERENT RATIO FROM ORIGINAL AND OUT OF LINE WITH THE CYLINDER.sORRY ABOUT THE CAPS. [smilie=ashamed.gif] .

bdkw1
06-15-2007, 11:59 AM
I use a 3/4 dia cylinders on mine and the only problem that came up was the foot pedal was overdriving the clutch slave cylinder. The clutch slave cylinder on a busa only needs about 3 mm of travel to disengage the clutch, with the foot pedal it was getting double that. All I had to to was build a stop for the pedal that limited it travel to what the cylinder needed.

I have been thinking of doing something similar. Hows the pedal pressure? *Feel?

rowycoracing
06-15-2007, 12:14 PM
The feel on the clutch when converted to a pedal can be a bit touchy. *Very little throw is required to go from full disengage to full engage. *That's not so hard to do with your hand and a small M/C master cylinder but harder to do with your foot and a full size master cylinder. *One one of my builds I made a simple rocker that has a 3 to 1 ratio. *The master cylinder moves a slave that pivots the rocker. *The other end of the rocker moves the stock cable. *The 3:1 ratio (slave moves 3, cable moves 1) improves the feel a lot. *My other buggy is direct (1:1). *New drivers eventually get used to the direct one after stalling it over and over again. *On the ratio'd one they can usually take right off first time. *Both have pedal stops to prevent overextending the cable and cracking the clutch cover/housing. *Both use a 5/8 bore master cyl ... that was the smallest I could find readily available at the time.

greasemnky
06-15-2007, 01:25 PM
The pedal on the left is the one modified directly from Wilwood. The one on the right is a bone stock forward swing wilwood pedal. You should be able to tell just by looking at the photo, you flip the mounting bracket vertically, then turn over the master so its in the correct position. Weld your tab on top, and viola, you have the same pedal as the one on the left.

Another trick I have heard of, but haven't tried, is putting in what amounts to a reducer in the line. Basiclly taking your clutch line, and putting in a "jet" if you will to restrict the fluid movement. No idea how effective it is, but I've heard of that method used on smaller road cars.

Rorty
06-15-2007, 06:06 PM
Try a much smaller M/C and/or a pedal stop as busasandrail mentioned.

boilermaker
06-15-2007, 10:18 PM
I would think that a restriction or a jet in the line wouldn't have much effect on pedal feel or pressure, but might have an effect on clutch releace, might encourage the clutch to be slow to engauge , might be a good thing for some people. I would like to hear from someone that's tried . Does it work like that or ????

LiveWire
06-18-2007, 07:57 AM
A jet won't work for altering the travel. You need a smaller master cylinder or a larger slave cylinder to alter the surface area difference which gives a leverage ratio. A restriction in the line would only slow the fluid transfer.

buggito
06-18-2007, 08:03 AM
It will slow the transfer both way and you don't want that, they have some regulator who work one way, that what I use for the rear brake , look for "flow control without check valve" we use them to control the speed of the cylinder in Hydraulic, but this will not give you "more feeling" as suggested before a smaller master or bigger slave are the only easy option.

masterfabr
06-18-2007, 11:28 AM
You hit the nail on the head there!