hello, new here, just got myself a 748, the clutch drags a little and its difficult to get into neutral. i've checked the clutch stack, its 38.5. i'm only seeing 1.45-1.50 mm of clutch lift measured at the pressure plate springs. this seems like its not quite enough? its got an oberon slave cylinder, the correct length push rod, i've bleed it several times, including at the banjo at the master cylinder. I've also removed the master cylinder from the bars, and tipped it to allow any bubbles exit etc. no leaks or loss of pressure overnight. it might be the case that i just need to ride it, and bed the clutch in a bit better, but in the absence of any dry weather i'm just playing with it on the drive any thoughts/ tricks? colin
The Oberon slave cylinder has a shorter travel than the stock one. You could revert to the standard slave to see how that goes. Make sure the master cyclinder is bled. I also run a little lithium grease on the steel plates when assembling it.
If everything is bled properly and there is definitely no leak I would check that the span on the clutch lever is set at maximum with a couple of millimetres of free play. Maximum travel at the lever gives maximum disengagement at the clutch. Stack height is 38 plus minus 2 in the manual so that should be fine. I wouldn't grease any plates, steel or otherwise! Isn't the Oberon slave a larger diameter than standard? If so it will have less travel for the same lever travel and it may not be enough to disengage fully.
thanks for the prompt replies. lever is set to 1 for max travel. i've had the plates in and out several times, they dont seem warped, although the convex plate doesn't seem very convex. i dont have the original slave, so cant try that out unfortunately. if anybody has a oberon slave and could measure the lift you are getting, it would help me understand if i need to play with the stack height or if i still have something not quite right in the hydraulics thanks
You are right, 1.5mm is on the low side, but can be enough depending on plates. You only need 2mm generally. with clutch cover off, and hand lever pulled in, can you detect play when you grab one of the clutch plate tangs and wiggle it - e.g. - can you make it "jangle"? This can give a clue as to whether you have enough travel for adequate disengagement. Without going through the usual suspects, just a long shot - have you tried testing with clutch cover off? If you have std steel cover but haven't also fitted the std rubber "gasket" then this can produce your symptoms.
it almost jangles, it does if i rotate the pressure plate backwards and forwards, but if i try to spin it, it stops as soon as i stop apply force. i do have the rubber gasket, but the cover and gasket have been off throughout. thanks
@johnscol1, just found the reference document I was looking for and it refers to the slipper clutch not the standard clutch, apologies for the red herring. Andy
as someone else has said, when you have all the plates out, do they all sit perfectly flat? And also do you know if you have one or two dished plates in there? If you had a couple of dished plates in there (one is standard) and they were both new-ish, then this could make a difference. Most dished plates naturally end up flat after a few thousand miles anyway, so probably isn't relevant. also as already said, when you go to pull the clutch lever, is the play minimal, approximately 10mm at the tip of the lever?, i.e.- does it feel like there is too much slack/it still needs bleeding?
38.5mm is on the thick side IMHO, especially with a larger slave cylinder. Both mine have larger slaves (Oberon & Evoluzione) and work perfectly but with a thinner pack. I set mine so that I can spin the clutch by hand whilst the lever is pulled in and it should run on a little, if it stops immediately you let go then you will have problems engaging neutral at standstill, this gives me around 37mm IIRC. I like the 1.5mm plain plates as they allow a better 'fine tuning' than the standard 2mm, allowing you to drop 0.5mm off the thickness without losing any frictions infact if you fit a few of them you can actually get an extra friction plate in the pack for the same overall thickness, especially if you don't fit 2 plain plates in the bottom of the pack (1 only works fine). Also (controversially to some) I don't use the dished plates, I see no benefit in doing so and my clutches both work perfectly and progressively with flat plain plates only. Of course if your clutch is a little thick and finding neutral is tricky, it will improve as it wears.
To add: My Monster (Oberon slave, RCS master) has around 1.5mm of lift and the 916 (Evoluzione slave, OEM master) has around 1.8mm. The Monster clutch setup is lighter than the 916 due to the master/slave combo and, IIRC the Oberon has a larger diameter than the Evo slave, so your travel sounds about right.
thanks guys, this is very helpful, i'll play with the stack height and let you how i get on. if i want some 1.5mm plates, is there a good UK source for these cheers
to close this out, and to thank those that gave advice. original problem was on a newly bought bike that had been stood for a good few months it was hard to get into neutral with the motor running. It was improved by restacking the clutch, and giving the drive plates a good clean and a bit of a polish, but it was still not perfect. after lots of clutch bleeding and staring at the Oberon slave cylinder i was no further forward. After getting advice here it seemed the 1.5mm of clutch lift was about right, so i looked at the clutch stack again. Swapping 2 of the drive plates from 2mm to 1.5 has brought the stack height down from 38.5 to 37.6. now it all seems to work normally, with just the slightest bit of freeness when you spin it by hand. The free float of the lever at the very end is about 11-13mm, and it feels great when trying it out on the drive way. just need to get a dry day to get it hot and give it the beans. many thanks for the assistance colin
