OzVMX Forum
Marque Remarks => Yamaha => Topic started by: POM on October 23, 2014, 09:57:08 pm
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All fibre plates measure up good so do steel ones,adjustment is good all the way back to lever,have tried numerous different fibre plates (none new) tried various oils.....any ideas?
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And the springs are well within tolerance......
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Try scuffing up the steel plates
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got an genuine yz465H myself [in an it250k] but never had the misfortune [yet] to get into the clutch--but--you say everything measures up so run out of ideas before i start. Not possible that for some strange reason the pressure plate [where it splines onto the center] is bottoming out on the clutch center & not compressing the plates up? or 'just' compressing then lightly. Perhaps add another steel at the back or put two together anywhere across should work [or prove a point--fix or not fix]. Has freeplay on the clutch adjuster? [on pressure plate]--it'll have more after adding another steel of course. I imagine they have straight cut primary gears but back in my RT2 days with helical [or what ever they're called] primary gears which had a bit of play between bearing on the mainshaft behind the clutch & the circlip holding it into the case, so that when the power was on the angled gears would pull it all sideways & make it slip if the clutch adjustment was too close [not enough free play]. Thanks.
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just found a parts pic of one & don't suppose someone put a extra thick nut holding the center on & the step on the mushroom thingy's coming up against that!!--ignore that idea, beer talk.
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Have tried extra steel plate (in different positions).....still no good.
All the steels are like new.......
All the fibres are old.....but as i said measure up ok...all very odd
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The fibres haven't had a dose of friction modified oil at some stage ??
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im thinking additives, try giving the fibres a good wet and dry scrub with about #400 or even #320 grit. get a flat surface like a glass plate and tape a sheet of wd paper down and give them a light scuffing to try and remove any FM's on the plates. give the steels a light scuff as well...then wack in some ATF -F the borg warner auto oil. it should help clean them up a bit. change it regularly.
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these clutches are normaly bullet proof. Gotta think outside the square [being silly here] had a Mk8 Pursang new & got a flatty during the race & had rim pins instead of security bolts & spun the rim inside tyre & couldn't climb a hill to finish line--Damn. [not that?--ok]. Carry on.--get new fibres in desperation no matter how good they look. As i say, strong clutch. When i had my 465G new in "80 i actualy did a 5th gear start in the soft wet muddy grass--maybe it was 4th but always thought 5th--filled them in to the first corner anyway. Poor clutch.
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Ok!...seemed to have sorted this...fitted extra steel plate in the middle of the pack.....
After looking closely the extra plate would not have worked at either end of the clutch pack, the pressure plate had a little wear on it and did not sit well with the steel plate.....same at the rear end of the pack.
Still doesnt explain why it slips when set up standard ????
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I know they are different type of thrust lever than the early DT-RT set up but I would be looking at actual free travel of the thrust rod, regardless of whether the cable has free travel.
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Pressure plate and/or basket worn, doesn't take much.
K
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how can you install an extras steel? somewhere there would be a steel against steel or am I missing the obvious?
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Was thinking the same Doc.
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Missing the obvious, due to the internal splines the steels always turn together, they never spin against each other.
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Having an extra steel (Which is wrong) without an extra fibre (which is also wrong) would be the same as having the correct amount of steels except one would be double thickness of the others ;)
Which would have the effect of tightening up the clutch pack therefore preventing slipping, This would fix the problem but not the cause, Something is wrong or worn with the adjustment, assembly or the plates themselves :)
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Steel against a steel is fine, done it before.
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Has the basket got wear grooves in the fingers?
Binding/restricting the plates from correct movement?
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Missing the obvious, due to the internal splines the steels always turn together, they never spin against each other.
yup..missed the obvious Geoff, if it were a snake it would have bitten me ::)
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Basket is very good condition.....pressure plate does have a bit of a wear lip on it hence the extra steel plate did not sit well against it....
Cable,operating lever,and push rod assy all seem good also......all a complete mystery.
However it seems to be ok now with the extra plate.....several clutch abusing starts up and down the street proved that.....neighbours just love me lol
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If there is a lip on the pressure plate etc then that gives less contact area which could be your problem, having to use an extra plate just doesn't sound right
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Have tried extra steel plate (in different positions).....still no good.
All the steels are like new.......
All the fibres are old.....but as i said measure up ok...all very odd
yer but what are the spring free length lengths are they in tolerance?
if the spings have lost length and preload, there's ya problem
pressure plates not worn?
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Steel against a steel is fine, done it before.
Fine maybe, If it gets you out of trouble,But not correct ;) A clutch is designed to have x amount of plates, any more or less to make it work means something is wrong ;)
The only exception to this is some aftermarket kits have one each extra but they are all thinner to still achieve the same stacked height, Only available for moderns I think though,something to do with giving better feel or hookup from memory :)
What may tell us more is details such as, Did the clutch slowly start slipping over time when previously all was good & untouched or has the motor been apart & rebuilt or the clutch assembly been removed & replaced or any part of the clutch from the lever down, one example is, Some bikes have a ballbearing inside the mainshaft between the pushrods if it is left out the clutch will not disengage, If the ball is too big it will hold the pressure plate too far out & the clutch will slip,I have also found two balls in there in some motors :o, Only one of many things it could be though along with what others have said :)
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The pressure plate has to go in one way other wise there is a gap between the last plate and pressure plate.
I found this out when putting a Yamaha one back in you have to turn the pressure plate around on on the diffrent studs for it to drop right down , because I through i left a plate out but it was the pressure plate sitting In wrong.
This might be the prob or not. That's why you can fit an extra plate in because the pressure plate is in wrong.
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Yep, That is another one that catches a few out,some bikes have a dot on the inner basket & an arrow or dot on the pressure plate to line them up,otherwise you just have to keep trying & turning the pressure plate on each one until it goes all the way on ;) :)
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Buy a new genuine set up.
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HERE IS THE ANSWER........
The clutch pack in this bike is very generic between models 250/465 from 77-81...I knew that...and wrongly assumed every part was the same.....ohhhhh nooo......after a lot of head scratching i read the fine print in the parts list.......the springs are different between 250 and big bore.....it seems i had some 250 springs in it ( which measure up the same as 465)....some decent springs and all good.
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the fine print..... >:(
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Have tried extra steel plate (in different positions).....still no good.
All the steels are like new.......
All the fibres are old.....but as i said measure up ok...all very odd
yer but what are the spring free length lengths are they in tolerance?
if the spings have lost length and preload, there's ya problem
pressure plates not worn?
now do you believe me