Hydraulic clutch feedback please

[Richard Negus]

Roger S is experiencing clutch drag with his hydraulic kit and I'm having difficulty diagnosing it from half-way round the world.Those others with hydraulic kits :.can you engage 1st gear when cold without a 'clang' or lurch forward? (ME - yes, no problem).can you select neutral with a running engine when stationary, hot or cold? (ME - yes, every time, hot or cold).how many miles have you done since the kit was fitted? (ME - 17,000).what grade of oil do you use in the primary? (ME - SAE10W-30 engine oil).what master cylinder do you have? (ME - Yamaha FZ750 type 1AE)Thanks,R.

[rustynuts]

.can you engage 1st gear when cold without a 'clang' or lurch forward? Yes.can you select neutral with a running engine when stationary, hot or cold? Yes.how many miles have you done since the kit was fitted? 2000; it was only fitted a few months ago.what grade of oil do you use in the primary? ATQ transmission fluid - on the reccomendation of I forget who.what master cylinder do you have? Yamaha Thundercat - dont know the type numberThe installation of the kit on my IP2 has completely cured the clutch drag. Has he dismantled and cleaned his clutch? In the past I found that removing the years of sludge build up from the clutch basket grooves with a cotton bud helped with disengagement.

[bodgerbloke52]

Thanks Richard for filing this one, good idea.To interested parties this is the situation as advised Richard. Master cyl is the correct Yamaha 5/8 item. Ajustment at the slave cylinder is a bit tighter than I prefer, no significant play. I extended the push rod slightly from M/C lever to piston to arrive at the very least lever play as possible. With 10/30 oil the clutch is unmanageable cold, somwhat better when hot but not acceptable.With ATF, much better but cold starts still have to be made with first gear engaged to avoid the subsequent big crash from neutral in first. The first few miles require carefull thottle control to match engine to transmission speed in order to be able to change gear. After the oil temp is completely up after about fifteen miles the situation becomes border line acceptable. Nuetral can be found with care at a stand still and gear changing is fairly reasonable.If the clutch is dropped moderately hard with some revs on the clutch is just slightly slow to become fully engaged and marked by a notable grab as clutch gets fully engaged. When fully warm this situation does not exist, the clutch operates as it should in take up of drive.I do not think it is a lack of lift or warped plates. If it was either of these causes the clutch would not improve as it gets fully warmed up.I am completely unfamiliar with a multi plate all steel clutch like this but do have many years of hands on experience with "normal" clutches ancient and modern.The symptoms suggest to me that the clutch drum is clogged with oil, perhaps due to any drain holes, if they exist, could be blocked up. In other words it is not a mechanical problem, it is a hydraulic problem where by plates are oil logged. This would explain why the very thin ATF fluid is much better and high heat will thin it out further.I am reluctant to dive into it without a better understanding of what to look for and what parts I should have on hand. Parts take a long time to arrive here and nothing can be sent back because of horrendous shipping costs.Any advise most welcome.Roger

[Dell Boy]

Please read previous posts I have put up regarding clutch drag.I have fitted Diversion clutch levers to both my Commanders which lift the diaphragm spring over centre allowing the plates to seperate.I did this to a horrendous clutch that would not do anything a clutch should do except drive the bike forward.Without stripping or cleaning the clutch it was sorted by fitting the Diversion lever.Took 21 years to find this solution & many, many clutch strips & cleaning.Derek.

[andygbsmith]

My clutch works fine with no drag or slip.Yamaha clutch master cylinderThe only complaint is the action of the gearbox being notchy.Andy

[bodgerbloke52]

Thanks fellersLooks like clutch drag can be a on going issue on some bikes but not others. Mine is unmanagable with 10/30 oil, only border line acceptable when hot on ATF, has to be started in gear when cold. Slave piston lift is .095" (2.41mm) which is a bit lower than Richards 2.57mmWhat is a "Diversion" clutch lever??? Is this for Hydro clutch or cable? Mine is hydro. If for hydro, where do I get such a thing??Roger

[Dell Boy]

For cable operation. Gives extra lift compared to the original lever.The Diversion is a later Yamaha than the XJ900.Derek.

[bodgerbloke52]

CURED ITThis dragging clutch was driving me nuts. Pulled out the plates, all seemed in perfect order. With nothing better to do, I removed the glaze on the bronze plates by hand with light touch emery on block backing.The steel plates I carefully touched up on my belt sander.Reaasembled, perfectly free on the bench. Then added F grade ATF which is designed for Ford automatics with bronze clutch packs. After 10 miles, the oil had soaked back in resulting in the customary drag nightmare.I had noticed that this clutch had a .033" spacer ring situated between circlip and diaphragm spring that did not exist in the parts catalogue. Back in again to scrutinise the "does not exist" spacer. Studying the lift action I spotted the diaphragm was not reaching the required "flat" area. Deduced that the spacer ring should be placed further in, between pressure plate and spring. This did have desired effect of compressing the spring just shy of flat zone with clutch fully engaged. At full lift, the spring was slightly past the flat zone into negative dish, it just looked and felt right.Back together with same ATF but slightly lower level. Cured it, I am a happy camper. Question, should the spacer ring be in there at all???, why not in parts book?Roger

[Dell Boy]

This has been a mod tried over the years to cure clutch drag.I tried it some years ago but it didn`t work for me.Derek.

[bodgerbloke52]

I take it that the spacer ring is supposed to be there and situated next in from the circlip?I understand that generally, diaphragm springs need to operate in the flat zone. This is usually achieved by clutch plate stack height adjustment, adding or subtracting plates.In our case it seems the spacer ring acts as stack height adjustment if placed between pressure plate and spring. It certainly made the clutch tolerable in my case. It is still on the heavy side and requires a full pull on lever for clean gear changes. I am however used to much better clutch action. Ariel Dry clutches, AMC clutches, BMW dry single plate and my muti plate wet clutch on H---A Deauville which is the sweetest clutch that sets the standard.As Richard suggested, come winter I may have a go at a hybrid clutch combining Commando and Commander plates, the Commando frictions are thicker which could result in correct stack hight with less plates.Roger