Lifespan of clutch plates?

[Velox]

Does anyone know roughly how many k's you should get out of the metal clutch plates (as opposed to the fibres) on a 1991 250? I know - it's a pretty rough guess because it depends on a lot of things. It's done 83,000k's so far. I need to replace the fibres at least and maybe the metal plates but I haven't taken them out because my bike needs some special tool to let go of the plates, and I can't have it off the road for ages while I wait for them to be ordered in.
Might have to end up forking out for both but it would be stink if the metal plates were actually still ok.

[Milky]

I'd hazard a guess at the lifetime of the bike. As you say it depends on how hard you use the clutch... The pressure? plates shouldnt need replacing as I assume they will only wear noticably once it is metal on metal.

I had the clutch out of PTs R65 - about 70000ks on it and there was very little wear noticable on the pressure plates. Given, it is a dry plate clutch and yours will likely be a wet plate clutch, so there may be some difference. Hopefully someone more knowledgable can help out...

[Bonez]

Does anyone know roughly how many k's you should get out of the metal clutch plates (as opposed to the fibres) on a 1991 250?

The '76 cb550 has done 145,000kms on the original plates. Must get around to putting in heavier duty clutch springs sometime.

[bungbung]

Give the wheelies a rest Velox, yer clutch will last a lot longer.

[Sniper]

On the same note, my CBR250 clutch seems to be on the way out, it only seems to "slip" around 16000rpm when I change from 1st to second and second to third using the clutch. If I dont use the clutch, it doesnt do it.

Is this the clutch plate, or is it just me granny shifting and being a nana rider or am I wanting too much out of the bike??

[F5 Dave]

The metal plates are unlikely to wear. In MX bikes with ally plates they need to be replaced at the same interval as the fibres but steels don’t really wear out.

However they can warp which requires replacement.

This is unlikely though so a set of fibres should see you fit.

Sniper, usually clutches slip when there is a large torque requirement/change like when they are asked to do a lot of work say accelerate up a hill in a non advantageous gear. However the change from 1st to 2nd is a large change in ratio.

At 16k the power has probably well fallen off (peak on these screamers is often well before redline) & then the revs drop down to likely where peak power is & you are asking the clutch to accept more power with the largest change in ratio in the gearbox.

Either way new fibres are in the future.

Velox, I’m surprised your bike is still running on that same clutch if it has been slipping that long. I suppose the diminutive weight & only being a 250 has done some favours here.

[scroter]

i dont know the answer to this but i had a TL-S with about 50000 on it when the clutch started to slip. i thought the same thing do the metals really need replacing. so i didnt. i just did the fibres and put heavier pressure plate springs in and this worked sort of, it still slipped when i first got on the bike but when i wound it up it would grab and then it would be sweet, slowly it got worse, suzuki suggested that the back torque limiter might be buggered(popular problem with that bike) but i decided to replace the steels instead and sweet bike fixed no more problems. once again this is just one experience i had so it might be different for you.

[F5 Dave]

Yeah the TLs do have clutch issues & another thing is we are talking a whole heap more power, it may be the steels had warped so they ‘cone’.

This can cause clutch drag as a side effect, but it also limits the effective area bearing on the frictions - if you see what I mean. So they weren’t necessarily worn any, but deformed.

[Paul in NZ]

Dunno if it applies to your bike but on a old pommie bike I stack up the steels and hold them up edge wise to the light. If I can see too many gaps they are warped and rooted.

Heat kills them quicker than anything else.

Paul N

[Velox]

Thanks for that guys.
Dave - it was only slipping at real high revs when I first told you, but now it's doing it a bit more, esp when it looses a little bit of traction (not the whole front end Bungbung ) at a particluar point on our road, but mostly just when I whack the throttle on pretty hard. All good though, it still does the trick!