airfruit Posted April 1, 2009 Report Share Posted April 1, 2009 I'm going to be replacing some clutch plates! The clutch has gone far out enough that I don't have any lever adjustment to bring it back in (04 rev 3). I'm just wondering if I should be doing friction plates and steel plates together or just friction plates... I am not exactly sure how to tell if the steel plates need to be replaced too? don't remember the original thickness and don't know how far they can wear! Is there some sort of dirty rules of thumb? like how many sets of friction plates per set of steel plates? This is the first time the bike is getting its clutch done. My brother bought it brand new and has about 2 yrs of riding on it... he was away for a while and is just getting back into it again! Me being the home mech guy... I have to work on his bike haha! I'm just wondering because I'm ordering some parts and I need to figure out what to order! Thanks all! Quote Link to comment Share on other sites More sharing options...
chewy Posted April 1, 2009 Report Share Posted April 1, 2009 I shall watch this with interest. Surely an hydraulic clutch is simply a column of oil/fluid being pushed and as such is infinitly "adjustable?. When somebody with more experience comes on I hope they can shed some light on clutch drag and patterened steel plates (to break the oil stiction I guesse) Quote Link to comment Share on other sites More sharing options...
zippy Posted April 1, 2009 Report Share Posted April 1, 2009 Well if it is your brother's bike then he is paying for the parts right? So just order all new plates (friction and metal) and give him some story about "optimum performance and just replacing friction plates will actually wear them out faster as they will have to bed in with the old metal plates." That way it's easier on your brain and you don't have to do much research just order and throw in. Just a thought Quote Link to comment Share on other sites More sharing options...
dave dix Posted April 1, 2009 Report Share Posted April 1, 2009 Its always best to replace both friction and steels together thou you can usually get away with just friction but worn out already? I would check the hydraulics for air etc just in case Dave Quote Link to comment Share on other sites More sharing options...
tombo46 Posted April 1, 2009 Report Share Posted April 1, 2009 I'm going to be replacing some clutch plates! The clutch has gone far out enough that I don't have any lever adjustment to bring it back in (04 rev 3). I'm just wondering if I should be doing friction plates and steel plates together or just friction plates... I am not exactly sure how to tell if the steel plates need to be replaced too? don't remember the original thickness and don't know how far they can wear! Is there some sort of dirty rules of thumb? like how many sets of friction plates per set of steel plates? This is the first time the bike is getting its clutch done. My brother bought it brand new and has about 2 yrs of riding on it... he was away for a while and is just getting back into it again! Me being the home mech guy... I have to work on his bike haha! I'm just wondering because I'm ordering some parts and I need to figure out what to order! Thanks all! buy a whole new clutch pack with the steels and fibre's. They are measured to very very fine tolerances to make sure the pack height is perfect. Hydraulic clutches are not infinatly adjustable, all the hydraulic system does is push against a series of "fingers" which in turn puts pressure on a spring which allows the clutch plates to slip, if the clutch pack height isnt right, these "fingers" can sit too low in the clutch basket and they will not put pressure on the spring when the "top hat" of the slave cylinder pushes on them. All the best Tom Quote Link to comment Share on other sites More sharing options...
chris morris Posted April 1, 2009 Report Share Posted April 1, 2009 (edited) maybe you've adjusted the lever so much that the master cylinder won't auto fill anymore. The piston in the master cylinder has to come nearly all the way out to allow the brake fluid reservoir to top up the system. on my 06 rev 3 i added some spacers behind the bolts on the clutch plates to give the clutch springs the gripping pressure they had when they were new, think i made them 11.5mm bore, 15mm outside diameter and 2mm thick, it just allows the clutch to grip a bit better Edited April 1, 2009 by Chris Morris Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 1, 2009 Report Share Posted April 1, 2009 (edited) Unless you've ridden the thing almost every day it would be unusual to wear a clutch so far it needs a full replacement after only four years. Can you tell us what the symptoms are? As pointed out, if the clutch is slipping or dragging it's possible you have the lever adjuster in too far so the reservior port isn't being uncovered at the end of the lever stroke. This causes the hydraulic system to be a "closed" system where either not enough fluid is in the system to completely disengage the clutch or the fluid heats up, expands and causes the clutch to never fully engage. Look at the master cylinder with the lever not pulled in. If the piston has not come back all the way to the snap ring you either have to back the screw out that pushes against the piston or you have to back out the screw that acts as a lever stop to allow the piston to come all the way back in the cylinder. It is also possible to have a weakened spring in the master cylinder due to a crash that smashes the lever in too far. The comment about clutch pack height and fingers and such is true for a "new style" Gas Gas clutch but not the Beta. Edited April 1, 2009 by Dan Williams Quote Link to comment Share on other sites More sharing options...
airfruit Posted April 2, 2009 Author Report Share Posted April 2, 2009 (edited) The symptoms are... I have the clutch adjustment screw on the lever backed all the way out, which let the piston come all the way back out... so that's not an issue... hmmm, I bled the system forwards and backwards... didn't see any bubbles... With the adjustment backed all the way out, his clutch engages almost the end of the lever throw, so all the way out. I basically can't back it out any further to bring the friction point back in a bit towards the bar! I am clueless! could there be something lose somewhere? need some spacers somewhere? ARGGGHHH haha I talked to some of the local guys here and they said they've only seen the problem the other way which you guys describes! that due to a crash the spring's weakened and the piston won't come back out all the way; thus, people screw the adjustment screw in... but my problem is totally the other way Edited April 2, 2009 by AirFruit Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 2, 2009 Report Share Posted April 2, 2009 The throw on a trials clutch is very short which means the range for adjustment is very small and any minor issue with the system can really mess up the works. Forgive me if this seems too simple. I'm not trying to insult. One thing I learned as a tech writer is start at the very basics as more advanced readers can skip over but novices need to be given enough info to get started. OK to make sure we're on the same page here. Is the clutch slipping when it is fully disengaged? Is the clutch dragging when it is fully pulled in? All I can understand from your post is that the engagement point is too far out. Fair enough. There are two adjustments on the lever. The first is the stud type screw that is in-line with the master cylinder piston. This screw adjusts the engagement point of the clutch. Screw it in towards the master cylinder and the clutch engagement point moves closer to the grip. Once that's adjusted to taste the lever stop screw that determines where the lever sits at rest must be adjusted out far enough to let the master cylinder piston come all the way out. That's pretty much it for adjustment. There is one other adjustment that is often forgotten and that is the position of the lever perch on the handlebar. Most trials guys run this fairly far from the grip to get more leverage. There have been reported instances of things like water being absorbed by hydraulic fluid and improperly drilled master cylinders but that sort of thing is extremely rare. Aside from assembly issues like leaving the ball bearing out that acts as a bearing for the push rod there's not that much to it. It helps to have the documentation, motor http://www.betamotor.com/system/attachment...t_04_motore.pdf chassis http://www.betamotor.com/system/attachment...0cc_veicolo.pdf On my last two Betas I've done a modification to the clutch fiber plates where I take them out and clean off the excess glue between the fiber blocks and smooth and polish the sides of the tabs. This makes a world of difference in the behavior of the Beta clutch. Details here. http://www.trialscentral.com/forums/index....15689&st=0# That's all I can think of at the moment. Quote Link to comment Share on other sites More sharing options...
airfruit Posted April 2, 2009 Author Report Share Posted April 2, 2009 Sorry if I am a little confused here... the stud type screw inline with the master cylinder, does screwing it in move the friction zone out? from my experience, if you have long fingers and want your clutch to disengage earlier when pulling the clutch lever in or engage later when you are letting the clutch out, you screw the stud screw towards the master cylinder. Using relative motion, by holding the stud in place and turning it (righty tighty) the lever will move out. Still hold the stud in place, and you turn it left, the lever comes towards the bar (looking from the lever side towards the bike). By having the stud extended more towards the master cylinder means it will actuate the cylinder earlier, meaning disengaging the clutch earlier in the lever travel. Sorry if I sound mean haha, I've been doing my engineering project for too long!!! Almost exam time... anywho Thanks anyways! Quote Link to comment Share on other sites More sharing options...
airfruit Posted April 2, 2009 Author Report Share Posted April 2, 2009 It would be so funny.................. if my brother bent his lever out slightly without telling me... HAHAHA. Good thing I got some new levers for comparison! Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 2, 2009 Report Share Posted April 2, 2009 No you're not confused. I'm an idiot. Got it backwards and as punishment I'll leave it there for all to enjoy. Only excuse it was past my bedtime. Quote Link to comment Share on other sites More sharing options...
airfruit Posted April 2, 2009 Author Report Share Posted April 2, 2009 It's ok! I'm a little confused about the whole clutch actuation with a hydraulic system. What are some signs for clutch wear? bigger friction zone? friction zone moving out? If it is anything like hydraulic brakes it should auto fill fluid if there isn't enough and the lever position should not change. And why would the fiction zone become bigger? You don't get squishier brakes when your pads wear? I worked as a bicycle mechanic for sometime... know them brakes but the clutch mechanics is a little confusing for me! Are the above just signs for a cable clutch? I'm too busy to think about it so someone feel like spoon feeding me with info? hehe Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 3, 2009 Report Share Posted April 3, 2009 Clutch plate wear usually just shows as slipping. Wear of the hydraulics usually shows up as inconsistancy of the actuation. Trials clutches do tend to actuate fairly far out since they try to make the pull lighter by having a longer lever throw then an enduro bike. Quote Link to comment Share on other sites More sharing options...
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