Wet clutch question

[slob]

Who's had experience of repacing plates on one of these beasties?
I've started to get clutch slip at about 8500RPM in top, when I'd really have been expecting to be hitting the limiter. Also in lower gears from about 7500RPM if I whack the throttle open too quickly.
Bike is a '02 620ie Dark with just over 12K on the clock.
My question is,
is it just the fibre plates that generally need replacing?
so I can assemble the parts before draining oil and stripping clutch.
Obviously I can measure the thickness of the metal plates once they're out but then I'll be without a bike while I order more parts.

[JMo]

Hi Slob - I had problems with my clutch slipping too - twice - replaced under warrenty... it was happening at much lower revs that yours, about 5-6000rpm in 4th gear typically, but only while the engine was heating up (between about 70 and 100° C typically, then it would be ok again...)

Originally I wondered if it was because I'd got the bike really hot once or twice (157°C no less! in summer traffic), as it first started slipping the day after that happened - but when they changed them the first time they said they found nothing wrong with the plates (which is why they did it under warrenty), and the same with the second time - although ProTwins put an extra plate in the second time which they felt might cure it...

If you give ProTwins a call they might be able to shed some light on it for you...

xxx

[Duncan]

Might seem a daft question but what oil you using in it?

Make sure its a motorcycle specific oil as these do not have the friction reducers contained in car oils. The friction reducers will cause clutch slip.

If the problem started straight after the 12,000 service then it could be odds on its the oil they use.

[slob]

I've noticed the low rev/fast throttle before but today is probably the hardest sustained thrash I've given the bike so far(Oil reached about 130c although it's been hotter in town in Summer). Ive only ever topped up with Shell Advance Ultra4. Service was just done by DLS, so I'd guess the same but I'll check with them. Methinks I'll observe a little longer before disassembling things.

[slob]

It's definitely getting worse. I had a chat with Ray at Rosso Corse yesterday, he reckons fully-synth. oil accelerates the wear on the clutch and recommended dropping the oil, flushing it out with cheap sh*t from Halfords, then doing a full oil and filter change with semi-synth. when I replace the plates, which weren't as expensive as I feared. I'll let you know how it goes.

[peteS4]

i changed the plates on chappers bike, was very straight forward and took about 1 hour 15 mins start to finish, didnt use the bike for a day or two though to let the liquid seal go off before i did the case bolts up real tight, also many people say never use fully synth oil anyway as dukes drink it, also told to use semi otherwise it gets past the rings,

[Lost Again]

I've noticed that my clutch is slipping too. when i wind on the throttle hard at low revs it'll start to pull a little bit then when the revs rise to about 4000 it'll start slipping. anything to do with the fact that I'm using fully synth. Only used it because the haynes manual said to use fully synthetic 5W/30. so thats what i used. have i knacked me clutch now? also noticed that it does indeed drink oil, odd seeing as i rebuilt it with new pistons, rings and barrels back in august.

[Spike]

If you can get it 50 weight oil is good for Dukes

[Pedro]

Oil burning may be a sympton of worn valve guide oils seals. If compression is OK (150psi ish) then this will likely be the cause of the oil burning.

[slob]

The bike 'drinks' about a litre every 3K miles, DLS reckoned this was normal. Plugs and (lack of)smoke don't suggest this is excessive.

[Ewan620]

I am also having clutch snags. As the revs pass 7000 on full throttle the clutch slips the revs to about 8500. The situation improves as the engine heats up but remains at all temps. Also under hard (well as hard as a 620 gets) acceleration the clutch also slips if you hit a bump in the road ie cats eyes etc. Is there anyway to adjust the clutch or any ideas what to do? The bike has done just under 7000 miles and the problem seems to have got slightly worse since the service. :mad:

[slob]

the clutch also slips if you hit a bump in the road ie cats eyes etc. sound like the back wheel spinning up(tyre slipping rather than clutch)
I changed my plates at 13K and switched to Rock Oil fully synth from Shell Advance. 2K miles and one trackday all is still good.

[Unit 18]

A good fully synthetic to use is Rock Oil Synthesis 4 Racing, its a 15/50 so is much better for the dukes than most which are normally 5/40's.