Can anyone explain this?

[Guest]

So as many of you know I have a Yammie FZ 750 that has either clutch or transmission issues that I'm having problems diagnosing. I found it hard to shift into 2nd and higher and had real difficulty finding neutral. A common consensus here and on other board is that I had a dragging clutch. Checking it, I found all the fiber disks to be out of spec and the steels to be badly scorched. I changed the whole pack for one totally in spec and good shape. That was about a month and a half ago.

I was also advised to change to some 5 weight oil and when I road tested, the bike did shift a bit better and I could find neutral but it wasn't anywhere near a 100%. I rode it around for about 20 minutes with no issues other than the sloppy shifting. On additional advice, I changed the oil to 15 weight but didn't get the opportunity to test it. I lost interest in it and just parked it for that month and a half. Nothing more was done to it.

Getting my enthusiasm back yesterday I hauled it out for another road test. The bike fired right up and once warm I dropped it into gear and it just died. I couldn't restart in gear so I tried to put it back in neutral but, once again, I couldn't find it. The bike would only shift between 2 gears but I couldn't tell what gears they were. with no neutral, I held the clutch in, rolled it back in to the garage and left it in disgust again.

I'm at a loss to understand this. The bike worked somewhat a month and a half ago, it wasn't touched until yesterday and it immediately went to crap again.

I will be tearing into it again on the upcoming long weekend but I just can't fathom what has transpired. Its one of the queerest things I've ever experienced.

Anyone with any ideas at all?

[Nessism]

Did you add the thicker oil since you last parked the bike? If so, maybe it's causing extra clutch drag. Other than that, get a GS.

[rustybronco]

A common consensus here and on other board is that I had a dragging clutch. Checking it, I found all the fiber disks to be out of spec and the steels to be badly scorched. I changed the whole pack for one totally in spec and good shape. That was about a month and a half ago.


Anyone with any ideas at all?

I am having the same issues with my '80 850. I found a few of the frictions and a coup of the steels out of spec. I replaced the frictions I had with another set (used) and installed the best steels I had as well. All the replacement pieces were well within spec, but used. It still drags, not as bad as it did when I first started, but none the less it's still dragging. No, there is no damage to the clutch basket or the hub.

I am of the opinion that once the frictions become sticky for whatever reason, be it old oil, or some other unknown reason, there is no way of undoing the damage and the frictions should be replaced with new. Preferrably with OEM pieces if possible.

One thing else you might consider trying is Amsoil. It helped the clutch drag on my '82 '850 considerably.

As always, for what it's worth.

BTW, "Yammie" sounds so metrosexual.

That's what I call Window 8's start screen; the metrosexual page.

[Steve]

Definitely sounds like the clutch is dragging.

Not sure if it is also a problem on the Yamahas, but check the clutch basket to see if grooves are being worn in the basket by the disks. Specifically, look in the channels in the basket where the tangs of the fiber disks ride. The inner surfaces of those channels need to be smooth to allow the disk tangs to slide sideways when you pull the clutch lever. If there are little notches for each disk, they are preventing the disks from sliding sideways to release pressure.

.

[Nessism]

If the clutch plates are not flat they will drag. Problem is you need a surface plate to properly measure flatness.

Resolved a difficult to find neutral issue on my second S by installing a fresh set of OEM fibers, and measuring and selecting some good steels out of the spares bin. Several were warped and worked fine other than the neutral business, but getting some properly flat clutch plates installed made all the difference in ease of finding neutral.

[spyug]

I did check all of the replacement disks and .as mentioned, they were all in spec for thickness. The steels were exceptionally clean almost like brand new. The basket was in good shape too with no signs of grooving. I will admit that I didn't check the disks for flatness other than by eyeball. I will pull them and check them on a glass plate.

The part that really confuses me is that a month and a half ago things were working, nothing else was done to it and then yesterday in a matter of a few minutes and with the bike not even moving, it goes to hell once again.

Thanks for the input folks.

[BigD_83]

Just throwing it out there, but the combination of heavier oil/having sat for six weeks...couldn't your plates be stuck together? Seems to me that problem has shown its head around here before.

[spyug]

oil/having sat for six weeks...couldn't your plates be stuck together?

It very well could be I suppose.

I did just put the bike up on stands and turned the back wheel and lo and behold, I was able to get it to shift once again and to find neutral. I'm not sure what that is telling me as I guess I'm having trouble understanding how a dragging clutch causes difficulty in shifting. I need to find a vid or animation of how things work together to see how it could cause these shift hangups and especially the difficulty in finding neutral. I can't picture it in my mind's eye. I'll keep thinking about it and maybe it will come to me.

Thanks again guys.

[GregT]

If you're doing your testing by hand then the clutch condition has no effect on shifting. By hand, rocking the back wheel while operating the shift lever you should be able to go through the gears and back to neutral.
Having the engine running just confuses the issue.
Rocking the back wheel back and forward will assist the dogs to line up and the shift should go through.

If it doesn't or you still can't go up past 2nd, than as suspected previously, you've got a selector fork issue.

[GateKeeper]

Getting my enthusiasm back yesterday I hauled it out for another road test. The bike fired right up and once warm I dropped it into gear and it just died.

Well this has me scratching my head, why did the bike die once dropped into gear ? did it lurch forward at all, or it didn't move and it just stalled ? It just don't make sense....

.

[spyug]

Well Greg, I did as you suggested and I can get all gears and neutral so it would seem the tranny is ok and its down to the clutch. A guru on the local board has been guiding me too and based on previous information I provided, it is very possible that the clutch hydraulics are not functioning correctly (specifically the clutch slave cylinder) and this is causing a dragging clutch. I'm going to dive into that tomorrow.

Thank you for the suggestion and method of checking. I'll let you know what else I find out in the coming days.

[spyug]

I'm not sure if it lurched when it died GK but it may well have as my man jac down here seems to think my hydraulic slave cylinder is the problem. He suspects its leaking and not throwing the clutch open when the lever is fully pulled. I'm going to dive into that again as I suspect he could be right. I tend to think it was leaking a tad before and may need a new seal kit.

Now with my luck that is likely to be the issue. I'll let you know what I find out tomorrow.

[GregT]

Well Greg, I did as you suggested and I can get all gears and neutral so it would seem the tranny is ok and its down to the clutch. A guru on the local board has been guiding me too and based on previous information I provided, it is very possible that the clutch hydraulics are not functioning correctly (specifically the clutch slave cylinder) and this is causing a dragging clutch. I'm going to dive into that tomorrow.

Thank you for the suggestion and method of checking. I'll let you know what else I find out in the coming days.

If it was a Ducati, that's the first thing I'd have suggested...lol.

Yeah, the hydraulic clutches just get forgotten about. They need fresh fluid just as often as the brakes.

[spyug]

Well I did clean and rebuild the master and slave when I first got the bike and I did change out the stock tube for a stainless one but I just reused the rubber seals which seemed ok.

There may have been some fluid weeping around the seals and air getting back in we now think. If this is the case, it may be that although the slave will push the rod out to disengage the clutch disks, the springs in the clutch over power it and push it back causing the disks to drag again.

I haven't pulled the slave off yet to check but I am suspicious of it as it didn't work at all when I first got the bike and I'm sure I did see some fluid around it where it sits in the side cover. I think, for peace of mind I should put in a new seal kit anyway as what's in it now is likely original.

I'll let you know what I find later today.
Cheers.

[spyug]

The slave's seals were leaking so I did order new seals which I expect the dealer to have in anytime now (they get their delivery at noon most days). When I ordered them I did speak with the shop manager and he confirmed our thinking about the clutch drag and went on to say its a common issue with bikes that have hydraulic clutch systems as people tend to ignore them and the seals wear out in 5 years or so.

I should be able to get it back together and tested this afternoon or evening and I'll let you know what I find.

Thanks for all the input.