Hydro Clutch problem

[wfooshee]

Shortening the pushrod isn't going to help. You're assuming the slave cylinder's piston retracts fully by itself (and I'm assuming it doesn't.) You still need the pushrod to travel as far as it's supposed to, and if you shorten it, the slave cylinder piston will only retract to the point the pushrod works rather than all the way back into the slave cylinder, unless there's a spring on the piston. (Hey, anybody, is there a spring in the slave cylinder? Does it retract by itself, or only under pressure from its load?) If the piston doesn't retract, then you're back to where you started on the next stroke: moving the piston too far. The slave sylinder piston will "travel" forward in the cylinder, same as a brake piston in a caliper as the pad wears. It's rest point will not be what you're expecting.

As for the measurement, that's the kind of info that could be useful to someone finding this thread later, which is why I made the comment about the PM. It's not a state secret, so why a PM???

 

[Nitrotate]

Shortening the pushrod isn't going to help. You're assuming the slave cylinder's piston retracts fully by itself (and I'm assuming it doesn't.) You still need the pushrod to travel as far as it's supposed to, and if you shorten it, the slave cylinder piston will only retract to the point the pushrod works rather than all the way back into the slave cylinder, unless there's a spring on the piston. (Hey, anybody, is there a spring in the slave cylinder? Does it retract by itself, or only under pressure from its load?) If the piston doesn't retract, then you're back to where you started on the next stroke: moving the piston too far. The slave sylinder piston will "travel" forward in the cylinder, same as a brake piston in a caliper as the pad wears. It's rest point will not be what you're expecting.
As for the measurement, that's the kind of info that could be useful to someone finding this thread later, which is why I made the comment about the PM. It's not a state secret, so why a PM???

I guess the way I'm envisioning it, the piston is already "capable" of moving further than it needs to or else it would not have pushed the rod too far so by shortening the rod, the piston's starting position would be in further and end in the same place but with the rod being shorter it won't push the pressure plate so far out that it pops the spring plate backwards.

No the piston does not have a return spring other than the pressure plate pushing it back into place.

Maybe I'm thinking wrong but I'll find out when I tear into everything and see for sure what happened. Maybe I'll post some pics to show what I mean.

Thanks for keeping the thoughts coming though, keeps me on my toes.

 

[nofreeride]

OK, Nitro, I'm sure you've thought of this, and there's reasons why you chose to do it the way you're doing it, but why not run the FJR clutch master cylinder behind the clutch pedal? You could make a suitable bracket and pushrod for it, and place it such that the appropriate pedal travel pushes the rod the appropriate distance.

 

[madmike2]

OK, Nitro, I'm sure you've thought of this, and there's reasons why you chose to do it the way you're doing it, but why not run the FJR clutch master cylinder behind the clutch pedal? You could make a suitable bracket and pushrod for it, and place it such that the appropriate pedal travel pushes the rod the appropriate distance.

I was thinking the same thing today. I came looking for this thread to post the same suggestion.

 

[wfooshee]

Shortening the pushrod isn't going to help. You're assuming the slave cylinder's piston retracts fully by itself (and I'm assuming it doesn't.) You still need the pushrod to travel as far as it's supposed to, and if you shorten it, the slave cylinder piston will only retract to the point the pushrod works rather than all the way back into the slave cylinder, unless there's a spring on the piston. (Hey, anybody, is there a spring in the slave cylinder? Does it retract by itself, or only under pressure from its load?) If the piston doesn't retract, then you're back to where you started on the next stroke: moving the piston too far. The slave sylinder piston will "travel" forward in the cylinder, same as a brake piston in a caliper as the pad wears. It's rest point will not be what you're expecting.
As for the measurement, that's the kind of info that could be useful to someone finding this thread later, which is why I made the comment about the PM. It's not a state secret, so why a PM???

I guess the way I'm envisioning it, the piston is already "capable" of moving further than it needs to or else it would not have pushed the rod too far so by shortening the rod, the piston's starting position would be in further and end in the same place but with the rod being shorter it won't push the pressure plate so far out that it pops the spring plate backwards.

No the piston does not have a return spring other than the pressure plate pushing it back into place.

Maybe I'm thinking wrong but I'll find out when I tear into everything and see for sure what happened. Maybe I'll post some pics to show what I mean.

Thanks for keeping the thoughts coming though, keeps me on my toes.

The length of the pushrod is not what governs the travel distance of the slave piston. The only thing you change is the starting position of the slave cylinder. The master cylinder still pumps the same volume of fluid (unless you change the stroke of the pedal or go back to the stock master) so the slave cylinder still moves as far. By shortening the pushrod, you risk actually pushing the piston out of the slave cylinder. Remember, it still has that volume of fluid behind it, and it will move just as far.

If the slave cylinder had a hard stop, then what you're envisioning would be correct, but I don't thik it does. It will move just as far as before, but do even worse things to your clutch because it's starting from a further extended position.

It was suggested that you go back to the stock master and rig up your pedal to that, but even that may not get what you need. If you bottom out the master cylinder's piston with the force of your leg multiplied by the pedal's lever arm, you might just push the end out of the case.

I think you should find a way to move the attachment to the pedal. The rod that bridges the pedal arm to the master cylinder should be moved towards the pivot of the pedal arm, down towards the floor since your pedal pivots at the bottom. You get two effects: you reduce effort because you increase mechanical advantage with a longer lever, but you reduce the stroke of the master cylinder so you reduce the amount of fluid pumped to the slave cylinder. The closer the attachment is to the pivot, the shorter the stoke is at the master cylinder. All it takes is to drill a hole, and maybe get a longer or shorter piece to make the connecting rod, depending on how it lays out mechanically.

 

[nofreeride]

Excellent thinking, wfooshee. A lot of these trike conversions also go with the stock clutch lever attached to the shifter, such that you both pull the clutch lever and shift with your right hand. I'm assuming that most of these setups had cable-operated clutches, though, and I think I would prefer the traditional left foot clutch. Let us know how this all works out, Nitro.

 

[Nitrotate]

Thanks for all the replies everyone. I'm probably headed out this morning sometime to go ahead and pull the clutch cover off and figure it out. I'll let you guys know what I find.

also to wfooshee's comment above; actually I think there IS a hard stop for the piston, that's why I was thinking that way. I'll have to check for sure but when I was looking at it the other day it appeared that it was built so that the case would stop the piston before it came completely out of the cylinder. Now the weird thing is that although it's built to stop the piston before coming all the way out it's not built to prevent it from pushing the rod too far in and popping the spring plate backward. :huh:

My original thought was to maybe just shim the piston from moving so far or to shorten the rod but it might just be easiest to limit the pedal movement, that way I won't be screwing with oem design of the bike.

I'm going to take some measurements and see if my theory is correct and then I'll let you guys know a little later on today.

 

[Nitrotate]

Ok guys I figured it out! So first off the spring plate was sort of the problem like I had though only it didn't get popped backward. What happened is since the pressure plate got pushed too far out it managed to get wedged up on top of one of the "teeth" for lack of a better word therefore keeping the clutch disengaged.

So I got it put back into place and bolted everything back together.

Now for the solution to the problem... The solution was MUCH simpler than I had anticipated! Safer, more reliable, and very quick and easy. I simply limited the pedal movement with some washers... done!

Thanks for all the great input and keeping me thinking because now I haven't messed with any of the bikes original designs!

 

[madmike2]

:yahoo: At least the repair was simple and not costly. :yahoo:

Good thinking on a pedal travel-stop. :clapping: