Hydraulic Clutch Conversion Basics - Write-up Added

[mrfreeze5]

After getting over some hurdles with the YZF swingarm, and some surprises in the parts themselves, i finally have the damn thing on. In retrospect, Im not sure I would have done it if I had known there would be so many issues, but now that I have them done, its not as bad as I thought. But the process definitely could have gone smoother for me. The kit is great, and almost spot on, but thanks to my setup i had to get creative with it to make it fit. Now, on to the good part.

Here is the installation process for my hydraulic clutch conversion using Modking's adapter kit. As always, the workmanship is fantastic, otherwise I woudlnt keep bugging him to do work for me. Included in the kit is the slave cylinder mount, 2 bolt spacers, and a new pushrod tip.



I did not want to have to take anything off my bike prior to the installation so that I could continue to ride while I waited on parts. This really meant that I needed to get a new clutch pushrod so I could modify it first and then just swap it with my existing one when I install the new stuff. So a few days ago I picked up a new pushrod from a local yard. Its a 3 piece rod, aluminum rod, with 2 hardened steel end. One is just a nub, the other is about 3" long and has a narrow tip. This one has to come off. Clamp the pushrod in a vise with 2 pieces of wood and apply heat with a torch to the aluminum near the long tip. Careful not to overheat, it doesnt take much. Clamp onto the tip with a pair of vise grips and twist and pull until it comes off.




Once it is out, apply more heat to the aluminum rod and push the new tip in as far as it will go. Take the rod out and put the new tip down on the workbench and lightly tap the pushrod with a hammer until the tip is fully engage. No gorilla smashes here! Modking suggested using a piece of angle iron to align everything while hammering. I didnt have any angle, so I screwed the 2 scraps together that I used to hold it in the vise to make a V, but didnt really need it. I used a friends torch but didnt have it to put everything back together, so I used the gas range in my kitchen and stuck the tip in the freezer for a few hours. It slipped about 90% of the way in for me and a few good taps and it was seated.




Now that the pushrod is done and all the parts are here, I can begin the install.

First, I removed the stock clutch lever and perch from the handlebar. Then I removed the sprocket cover and pulled the cable through the bike and set it aside. I really liked my red sprocket cover and I am sorry to see it go. It gave a nice splash of color to the black. Oh well, function over fashion. Now is a good time to clean all the funk out of there. Its surprising how fast this gunk builds up.

Remove the stock clutch pushrod by pulling it straight out. Stand the bike upright while removing the pushrod as oil will want to come out the hole. Install the new one quickly to minimize oil loss.

Next, install the slave mount. There are 2 bolt spacers, a short and a small. Short goes at the top, the long one goes at the bottom. This is where I encountered my first major problem. I forgot to mention that I was running a YZF swingarm and that my front sprocket is offset 8mm outward. With the included spacers, the bracket hit my chain and was nowhere near close to fitting. After taking a break and coming back later more clearheaded, I was able to find a simple method to space it out the necessary distance. I went to Ace and bought a handful of different parts for different ideas. The simplest was the one I chose and it seems to work out OK so far. I used M6x50 screws as well as some shorter ones for the water pump from my hardware bin. I put a hex nut and a jam nut threaded together onto the ends of the screws after the included spacers top and bottom. Or in the case of the 2 bolts that replace the water pump cover bolts, the nuts go between the slave mount and the pump cover. One of the screws for the water pump cover needs to be a full thread screw, and not partial like most M6 screws. The buts have to go all the way down to the backside of the cover so it will sit between the pump cover and bracket. The nuts I have thickness worked out perfectly. The jam nut plus the hex nut=8mm thickness. This way, I did not have to be so precise trying to make new longer spacers, and could evenly space the whole bracket outward easily. I have about 2mm of clearance now with my chain. Its close, but it should work. I dont think I will be able to go up to the 15 tooth front sprocket that I wanted to though, unless I space the thinkg out more. I still might take it back off and shave it down near the sprocket. Its damn close.




The kit includes a new tip for the pushrod that is longer, and it should be the right length for a normal FZR, but on mine, since I spaced it out more, I need to compensate for it at the pushrod. A ball bearing is the common method and I happened to have a few upper stem bearings from some USD front ends that dont fit anything and I have no use for, until now. They use 8mm roller balls, so I grabbed one and popped it in the slave. Theyre also available at Ace. I also applied a healthy dab of grease to the bearing before dropping it in the salve cylinder.

I didnt realize until I got the kit that the Ducati slave cylinder needs the little ears on ends of the mounting face ground off to fit in the bracket. Not a big deal to do, just a few minutes with the grinder. But if I had known prior, I would have sent the good slave off at first instead of the spare one. Once I get motivated one day, Ill grind down and repaint the nice one so it fits.

Now its time to install your clutch master cylinder of choice. I opted for a Brembo radial unit off of an 07 Aprilia RSV1000. After a few coats of paint, its ready to go on my bike. You will need to fab up some sort of bracket to bolt the resrvoir down depending on the type of MC you use. Luckily, mine came with the stock bracket. It wont take much to mount it for me, I just need to drill and tap a small hole on the bar. Not having a clutch cable really cleans the front end up.



Route the hose through the bike. I used a stock Ducati SS clutch line. I think it is for a Monster. There are 2 different kinds of hoses that I have seen, one has almost straight banjo bolts, and one has 90* banjo at the MC. I used the kind with the 90* bend, but I flipped it around and used the 90 at the slave, not the MC, it allows for a much better fitment. Frankly, I couldnt have made it fit the other way. So if youre buying a new hose, I recommend looking for the one with one bent banjo.

Fill the slave cylinder with fluid to the top first and then install the hose and banjo bolt. Then install the slave cylinder onto the mount, over the pushrod. This should push fluid back up into the line so no bubbles are caught in the slave while bleeding. It should make things a little easier. But the components I used, the radial MC especially, make it really easy to bleed.





Fill the reservoir and bleed the system.

After I got everything bled and tested the clutch function with the bike off, it seems to be in proper working order. The lever feel is very soft. The only issue I am having is a lot of free play in the lever before the clutch disengages and is probably a result of spacing it outward. I think I need to add another ball bearing inside the slave, but that might be too much. Im still weighing options on this one. As it is now, so long as I leave my lever on the top 2 or 3 settings its ok, otherwise it hits the bar before the clutch disengages fully. It might be just be that it feels so soft, there is very little resistance to the lever. But my bike decided to die on me yesterday and I am working on the carbs tmrw, so I cannot test ride just yet, or even fire it up and test it out in the yard. Its very angry with me right now, but I think I know why. I blame warm weather in winter.

After I ride on it a bit, I will give some feedback on the setup. I still need to pick up a clutch switch for this MC. Right now I have the connectors jumpered together, so until I get one Ill have to be mindful not to start the bike in gear without my hand on the clutch. I am going to stop by an Aprilia/Ducati dealer once the bike is running again and see if they have one in stock.

Lots of credit to Modking who did great work and hooked me up big. I can always count on his work and cannot recomend strongly enough to someone looking to do this mod. MK is the man to talk to. His hard work has taken all the guess work out of this project. Unfortunately, I dropped the ball a little and forgot to mention my sprocket setup, but since when was anything easy on my bike? I will probably need to make a few more small adjustments here and there to get it exactly how I want, and I will be sure to include any changes I make. For the avaerage FZR owner, this should be a much simpler process than mine was. I ran into a lot of issues and if I had to go through the same again, Id think twice, but I think it will be a good mod, and should help with the stress on my left wrist. Plus it really cleans up the front end. Not having that clutch cable helps me a lot. It would push down on my headlight whenever I turned and move it around. Plus, with stock routing and low R1 clipons, it had a pretty tight bend to it. The adjuster was a pain in the ass, and when I removed it I found my 1000mi old cable was already fraying inside it. Now I just need to get some damn shorter throttle cables and maybe bring the light up a hair and Ill be all set up top.

[mrfreeze5]

Since I spaced the bracket out, the slave cylinder was not engaging at the right spot in its motion, so I had to add a ball bearing inside. Unfortunately, this left quite a bit of free play in the lever since it still was not in the right spot. So I added another ball bearing. To add a second bearing, the pushrod had to come back out, the bearing inserted into the hole, and the pushrod reinstalled. This isnt so easy with the bracket still installed, but a small magnet or a pair of hemostats should do the trick. This is the normal method for extending the pushrod when doing a hydro swap on a stockish FZR. A ball bearing in the slave and inside the engine is about the same as the extended tip I got, which eliminates the need for balls in most cases. But mine has balls Unfortunately, 2 bearings is a bit too much and the bike would roll freely in 1st gear. So I removed the slave cylinder, got some longer screws, and installed a jam nut(~3mm thick) against the backside of the slave to space it out from the mount. I then carefully tightened everything down making sure everything was snug against everything.

After a quick cleaning of my trying-to-foul plugs, the bike fired right up and I was able to test the clutch function at least on the patio and it works so far. I need to wrap up a few things on the bike and then Ill be headed out for the maiden test voyage later. So far, I like the feel of it now that everything is where it should be. It is a little firm, so I may upgrade the slave cylinder later, but its most definately smoother than the stock cable clutch. Going to take some getting used to though.

[mrfreeze5]

Just took the first ride on the highway with it and its pretty nice. The lever throw is shorter now and a few times on a downshift I broke the back tire loose because of it. Time for a slipper clutch huh? The movement is much smoother than the cable was and the pull is lighter, but it takes constant effort to hold the clutch at a light. Not too bad. It really has smoothed out the point where the clutch begins engaging. It was a little harsh with the stock setup and would often cause a slight buck, but thats not an issue at all now. It gives the bike a completely different feel. Gonna take some getting used to, but I like it.

Luckily the engine behaved long enough to get to the dealer and pick up my jets. Now I get to see whats wrong with my carbs.

[thatkid]

Hey, how long was that end piece? I may want to make one for my setup.

[trifgeorge]

i bought a fzr 1000 complete hydraulic clutch to put onto my 1992 600. Did all the fittment and stuff ( took out the cable clutch mechanism from the sprocket cover, enlarged the hole to be able to put in the 1000 slave cylinder,lenghtened the push rod) , the system is air free 100%, BUT the pussing rod doesn't go in as much as it was with cable one and the clutch does not disengage. How can i solve this?? From my point of view, the piston in the slave cylinder is not having enough movement to be able to push the rod all the way in.

[mrfreeze5]

i bought a fzr 1000 complete hydraulic clutch to put onto my 1992 600. Did all the fittment and stuff ( took out the cable clutch mechanism from the sprocket cover, enlarged the hole to be able to put in the 1000 slave cylinder,lenghtened the push rod) , the system is air free 100%, BUT the pussing rod doesn't go in as much as it was with cable one and the clutch does not disengage. How can i solve this?? From my point of view, the piston in the slave cylinder is not having enough movement to be able to push the rod all the way in.

I had to fine tune the spacing on my hydro setup to get proper lever/pushrod engagement. An 8mm ball bearing will fit into the pushrod's bore in the engine, and one can fit inside the Ducati slave cyl I used, but I dont think one will fit in the yamaha one IIRC. I had to use a combination of ball bearings to add some length, and some steel sleeves as spacers to adjust the slave cylinder mount out from the engine. I got lucky and found some pieces of steel tubing the correct size at the mom and pop hardware store near me. I had to cut it to length, so I used some nuts threaded onto the screws first to figure out how much of a spacer I needed, and to have some adjustability in the fiddling process. It took an afternoon of fiddling with the clutch setup before I got it to a point that I liked.

[trifgeorge]

so i should put a 8mm bearing ball inside the transmission before i put in the push rod? should i put it trought the hole where the push rod gets in? wouldn't that be the same thing as adding 8mm to the push rod? which is the part the bearing ball is playing into making hydro work?

[mrfreeze5]

so i should put a 8mm bearing ball inside the transmission before i put in the push rod? should i put it trought the hole where the push rod gets in? wouldn't that be the same thing as adding 8mm to the push rod? which is the part the bearing ball is playing into making hydro work?

Right, you can put it in before the pushrod to add 8mm in length. As is, this will probably be too much, so you will have to space the slave cylinder out slightly to compensate to find the happy medium, but it gives you some adjustment room if you were maxed out before. I have a 8mm ball bearing inside, plus another one inside my Ducati slave cylinder, but it is also spaced farther out to clear my front sprocket(spaced out for YZF swingarm swap). It is possible too that the slave cylinder's throw just isnt long enough though.

[trifgeorge]

i think that, as you said, the cylinder's throw is not long enough, because the rod is moving as soon as i squeeze the clutch handle but it seems like is not beeing pushed inside enough so that it can disengage the clutch. that is why i mounted the slave cylinder onto my OEM sprocket cover, so that it will clear the sprocket when i will do the rear wheel swap.

[yamaha_george]

i think that, as you said, the cylinder's throw is not long enough, because the rod is moving as soon as i squeeze the clutch handle but it seems like is not beeing pushed inside enough so that it can disengage the clutch. that is why i mounted the slave cylinder onto my OEM sprocket cover, so that it will clear the sprocket when i will do the rear wheel swap.

TG,
Its not the slave cylinders fault the M/C pump ratio is not big enough you are simply not moving enough fluid per lever pull to shove the slave units piston & therefor the push rod to disengage the clutch plates.

[trifgeorge]

i think that, as you said, the cylinder's throw is not long enough, because the rod is moving as soon as i squeeze the clutch handle but it seems like is not beeing pushed inside enough so that it can disengage the clutch. that is why i mounted the slave cylinder onto my OEM sprocket cover, so that it will clear the sprocket when i will do the rear wheel swap.

TG,
Its not the slave cylinders fault the M/C pump ratio is not big enough you are simply not moving enough fluid per lever pull to shove the slave units piston & therefor the push rod to disengage the clutch plates.

YG,
...... then if I mount a smaller slave cylinder it will change the power ratio..... I think...
Tomorrow I will go to my machinist and see what i can do.

[yamaha_george]

i think that, as you said, the cylinder's throw is not long enough, because the rod is moving as soon as i squeeze the clutch handle but it seems like is not beeing pushed inside enough so that it can disengage the clutch. that is why i mounted the slave cylinder onto my OEM sprocket cover, so that it will clear the sprocket when i will do the rear wheel swap.

TG,
Its not the slave cylinders fault the M/C pump ratio is not big enough you are simply not moving enough fluid per lever pull to shove the slave units piston & therefor the push rod to disengage the clutch plates.

YG,
...... then if I mount a smaller slave cylinder it will change the power ratio..... I think...
Tomorrow I will go to my machinist and see what i can do.

TG,
that is the hard way of doing it.
You need to Know the bore of the pump on the handle bar and get a larger one .

[trifgeorge]

TG,
that is the hard way of doing it.
You need to Know the bore of the pump on the handle bar and get a larger one .

When you say bore , you mean the inner cylinder where the spring is, or the hole that is marked with red in my picture?

[yamaha_george]

TG,
the bore is the piston diameter of the pump, the actual bit that the lever pushes on and that actually governs what volume of fluid is actually moved when you pull the lever up on the handlebars.
If the diameter is small you move less fluid down the hose to push on the slave units piston. using a bigger bore unit will move more fluid down the hose to shove the slave unit piston & the push rod moving the clutch into disengagement.

There is one minor thing tho the more diameter the handle bar piston has the LESS work it actually does so you the rider have to put more energy into the lever to get the clutch to disengage.

The handlebar lever bore & the slave cylinder bore work like gear ratio's in this respect.

[trifgeorge]

I got it george. but what if i shorten the spring that is inside? wouldn't that make it squirt out more liquid?