clutch questions... *technical*

[benHallowes]

hi guys,

my clutch has started slipping and making a slight whirring noise when really spanking it (on track and accelerating hard off the lights and slipping it slightly to keep the front down!)

Also the bike has done 24k miles...

So, do i need to replace:

- just the clutch plates & springs
- the whole clutch basket inc plates & springs (how will i know if the basket is ****ed?)

OR

is it worth buying a used basket, springs and plates for £83 with 7k miles on it (from r6parts) or just new friction plates and springs for £53 (patternparts.net) - s'pose i could go for uprated (kevlar) friction plates & springs for £70... (dunno what difference that would make?)

The thing is, i've been told that the steel plates (?) may be warped and/ or the basket may be scored! - wtf?

OE baskets *new* (inc. plates & springs) are £385 from Yamaha - what a nightmare!

arrrrrgggggghhhhhhh!

[Amanda M]

It's a yamaha - they all do that sir :wink: Seriously - yamaha clutches are rubbish. I've had to replace the clutch on my yam and put heavy duty plates and springs in it and that's helped. It's still rubbish but it helped.

[benHallowes]

cheers amanda!

up til recently its been faultless, but its all of a sudden started slipping... :roll:

[454697819]

My best Geuss would be,
up rate springs and plates as you do use it for the track, buy them in ready to fit, when its apart, if the basket looks damaged then replace it with ta second hand one.

my 2p
Alex

[zx6man]

and use semi-sythnetic oil. Fully synthetics can cause slip, especially if its a bit old.

[Sid Squid]

First off, if the clutch is slipping it will make all sorts of duff noises so don't worry until you're sure that there is nothing that can be done with the adjustment, and be certain that the lifter and cable are working perfectly.
If that doesn't get you anywhere, then you'll need to get the clutch case off to see what's up, first check the friction plates, these are the ones with the driving tangs on the outer edges, you'll need to measure them with a vernier or micrometer at several points to see if they're worn below their minimum thickness, replace if necessary.
Even if they are worn it may not be the only problem, the plain plates, the ones with the driving tangs on the inner edge, rarely wear, but if they've got very hot they can warp, if they do, even if you fit new friction plates the clutch won't work right, (judder and uneven drive pickup is a common symptom).
Measure the clutch springs too, they can settle quite quickly, especially if the clutch has got hot enough to warp the plain plates
The clutch basket can wear where the tangs of the friction plates engage with it, if there is wear you'll see a series of scalloped markings along the driving face of the basket, minor wear can be dressed with a file but only if it really is minor, check the centre hub for the same sort of wear where the plain plates engage on it, the plain plates are thinner so if hub's worn dressing the faces is not viable. This sort of wear makes the clutch drag or disengage awkwardly, if you're not having that sort of trouble it's most likely just the plates.
Give the basket a wiggle while there are no plates in it, it will move a little back and forth, just enough that you can feel it, but if it rocks perceptibly from square, or moves radially at all the centre bearing and/or bush need a look.
Check the release bearing carefully, these are usually pretty cheap, so if it's not perfectly smooth, bin it.
Yamaha clutches are a known weak spot, so to avoid trouble I'd spend the money for a new Yamaha parts rather than pattern bits, or second-hand, excepting if you find parts from one of the premier makers, Barnett for example.

[benHallowes]

cheers guys!

Sid, that's a pretty comprehensive breakdown! :!: Thanks!

Best call is to take it apart and drive the poxy car for a while, to give me the chance to examine it and get only the bits i need, rather than forking out for bits that may not be worn!

btw - is anyone able to offer an insight into what advantages/ disadvantages the kevlar fiction plates might offer - some people have said to me on another forum that they're harder wearing and better for heavier riders, is this true?

Cheers again!

Ben

[Sid Squid]

Kevlar friction plates do wear better, as far as heavier riders go I can't see how that would help, they just last longer, in my experience they don't 'work' any better.

[johnnyrod]

Sid squid has it alright. I believe a trick with the original FZR600 was to add an extra plain plate to make the clutch work better, when it got a bit of hard use like on the track or whatever. Defintely check the surfaces of the basket and hub where the plates bear on them, if you've not been too careful with gearchanges and got on the gas a bit early while letting the clutch out then the plate edges could have rubbed a bit of ally off. I had this on an old GPX750 (what the hell did I ever have one of those for?).