Clutch resistance

[Manxkiwi]

So it seems my thought could still be a possibility? The slip/assist ramps might be sticking slightly (stiction). Did you try rocking her back in gear then seeing if you get the same feeling?

[petshark]

17 hours ago, Manxkiwi said:

So it seems my thought could still be a possibility? The slip/assist ramps might be sticking slightly (stiction). Did you try rocking her back in gear then seeing if you get the same feeling?

Sorry I forgot to get back to you on this. I can't replicate the issue by this way, it's still a smooth lever pull, I tried first and second gear and pushed the bike both forward and backwards against gear.

Side-question: Is it normal that the clutch does not let go when pushing against a gear and then pulling the clutch (engine off)? I have to push past a barrier and then it starts rolling again but hesitantly. I guess it's normal and to do with the fact that the oil is cold and the plates are sticky but just checking (and learning).

17 hours ago, thewrenchbender said:

Jet world is a little different as the sole technician, I perform “line maintenance” only-and travel with the aircraft to larger maintenance facilities once a year for scheduled inspection events. Have to be able to troubleshoot literally every system at the very least to determine if it’s a job I can accomplish in-house or make arrangements to have repaired at a facility with more capabilities (I.e. special tooling and/or more techs).

I have never noticed the bump/s on decel, it just feels like a slipper clutch to me (most experience with one is on an ‘08 R1).

I have been sorta randomly experiencing it on accel since I did the first service on it and started riding it like I stole it. Until reading your post, honestly never thought about it, just figured it was an Tracer thing. If I am going to feel it, is during moderate accel, typically when increasing throttle while clutched-shifting. Balls-to-the-wall I’ve never felt it, but then again, most of the time just use the quick-shift feature.

Real interesting to hear what goes on behind the scenes of air travel. I hope you get paid well for all that responsibility.

It still sounds like you have the same issue with your Tracer. I've always used the quickshifter for balls-to-the-wall acceleration so there's another test I can do but apart from that normal shifting during fluid constant acceleration always causes the bumps. If I just let go of the throttle and grab the clutch 2 seconds later there are no bumps.

I'm really just learning how this all works but my guess is that the reason for the above is that the forces of the engine and the rear wheel have to slam into each other for the clutch to behave this way.  The moment where I let go of the throttle to shift and the wheel starts dragging the rpm down... if I pull in the clutch at that exact moment that is where it happens and nowhere else.

If you have the time when you're on a ride perhaps you could also try these tests:

-At cruising speed. Stay on the gas when you pull the clutch. The RPM skyrockets but no bumps on mine
-Preload the gear; gently push up with your toe and hold and they pull the clutch, the gear just slides in to the next smoothly and no bumps (and you only need to pull the lever a few millimeters)

I'm sure this all means something but I know too little about the clutch to figure it out. @Manxkiwi suggestion sounds like it's in the ballpark of what's happening. I'm willing to take mine apart but I need a clear idea of what I should be looking for.

 

Edited March 7, 2021 by petshark
Readability

[skipperT]

@petshark everything you’re describing is normal for a slipper type clutch. it’s designed to absorb the shock/abruptness when rear wheel speed doesn’t match engine speed, and also provide better engagement under acceleration. What happens is on the inside of the clutch (pressure plate, clutch plates, etc) rotates slightly on ramps which also causes the plates to open up slightly and overcome the pressure of the clutch springs. This briefly allows “slip” and absorbs some drivetrain shock before wheel speed and engine speed match again and everything engages as normal (when lever is disengaged). The whole assy fits inside the primary gear, which does NOT have springs on the back side (I’m still mystified as to why Yamaha didn’t use springs there which is more typical than not, but I’m guessing it was an engineering decision. )

Some riders may be sensitive enough to feel some of this happening at certain times while shifting, which I think-now that you’ve replaced your cable- is probably what’s going on.  
If you want to still take it apart, by all means - it will only cost you time and a clutch cover gasket. 

(I’ll go find a decent visual explanation and post it here in a second which may help. )

This video was shot before Yamaha released the FZ/MT09 however our clutch works the same way.

and 

(The first style he shows is KTM design but the assist and slipper one he talks about second is pretty much our exact clutch, notice the pressure plate allows for 3 springs).

Oh and it’s normal when the engine is not running (pushing around the garage or rotating the rear wheel by hand) to not have the shifting action engage positively all the time. when the engine is off there are too many parts not moving, that would normally be moving, to help shifting engagement.  It’s common to have it only “1/2 shift” or “get stuck” between gears as well.  No oil pressure affects this as well.

-Skip

Edited March 7, 2021 by skipperT

[PhotoAl]

@petshark your posts have been interesting and have stired a lot of good discussion that has been educational for me.  

[petshark]

4 hours ago, skipperT said:

everything you’re describing is normal for a slipper type clutch. it’s designed to absorb the shock/abruptness when rear wheel speed doesn’t match engine speed, and also provide better engagement under acceleration. What happens is on the inside of the clutch (pressure plate, clutch plates, etc) rotates slightly on ramps which also causes the plates to open up slightly and overcome the pressure of the clutch springs. This briefly allows “slip” and absorbs some drivetrain shock before wheel speed and engine speed match again and everything engages as normal (when lever is disengaged). The whole assy fits inside the primary gear, which does NOT have springs on the back side (I’m still mystified as to why Yamaha didn’t use springs there which is more typical than not, but I’m guessing it was an engineering decision. )

Some riders may be sensitive enough to feel some of this happening at certain times while shifting, which I think-now that you’ve replaced your cable- is probably what’s going on.  

Thank you for this, very educational indeed. 

This all makes sense but the thing that bugs me still is that I bought this bike with 7300 km (about 5000 miles) on it. I rode it for more than a month without anything like this happening. This all started right in the middle of a 2 hour ride. At first every couple of gear-shifts, then maybe half the time. I arrived at the destination where I asked a mechanic to check the cable. He found nothing wrong with it and suspected the after-market lever. On the way back I noticed it happened almost all the time and I remember hoping the clutch would hold until I got back. It really felt like something was about to break before I got used to it.

I got a new piece of the lever sent to me under warranty and that didn't help. The seller was stumped and sent me a complete new lever. When that didn't help, I installed the OEM lever again and found out that it was not related to the lever after all so I started this thread.

 

@thewrenchbender
I tried balls-to-the-wall acceleration without the quickshifter and indeed, no bumps! (because of high RPM?)
I also tried abnormally short shifts, not going higher than 2000 RPM and also no bumps. So I think we can establish that it only happens within a specific powerband, unfortunately that powerband is very wide.

[Manxkiwi]

A great couple of videos there. Very clear in showing how those/our clutches work.

I just went out and rolled the bike around in gear with clutch pulled in (obviously), there is no undue resistance from my clutch, backwards and forwards the same. I wonder if you have an issue with your plates? Given what you say about its resistance to being moved in gear..

[petshark]

2 hours ago, Manxkiwi said:

A great couple of videos there. Very clear in showing how those/our clutches work.

I just went out and rolled the bike around in gear with clutch pulled in (obviously), there is no undue resistance from my clutch, backwards and forwards the same. I wonder if you have an issue with your plates? Given what you say about its resistance to being moved in gear..

Could this be an oil thing? I use semi-synthetic which is less slippery. 

[Manxkiwi]

I doubt that would be the issue, as semi synth is recommended by Yamaha. Sounds like you have unusually high drag in the clutch. Could it be the fibre plates deteriorating? That would be unusual, but not impossible..

[petshark]

1 hour ago, Manxkiwi said:

I doubt that would be the issue, as semi synth is recommended by Yamaha. Sounds like you have unusually high drag in the clutch. Could it be the fibre plates deteriorating? That would be unusual, but not impossible..

Did you test with cold oil? I redid this test after a ride and I could walk around in gear and the clutch in without any resistance.  
 

Another thing that troubles me is a kind a bang or thump in the engine mostly felt in first gear when letting the clutch out either for acceleration or engine breaking. There is a small delay, then I feel this bang in the footpegs and then  the energy of the engine and wheel are in sync. I checked the chain and it is exactly ik the middle of the spec. 
 

Does this sound familiar? If not it could also be part of the problem. My Versys felt a lot more robust engine wise at low speeds. Characteristics of this engine or is something broken? I honestly have no idea, I’m going to try to find another GT to ride and compare.

[Manxkiwi]

Yes, cold. Bike parked in the garage. Temps around 20c here at the moment.

I must say, all the things you are saying makes me think it might be worth a look inside the clutch. That 'bang' you mention doesn't sound right. I'm still thinking ramps and/or plate issue? Without an inspection it's all a bit of a guessing game.

Cheers and good luck.

[Ride365]

On 3/7/2021 at 7:01 PM, petshark said:

Could this be an oil thing? I use semi-synthetic which is less slippery. 

 

Synthetic isn't more slippery than conventional …..total old wives tale and oil folklore.  

[petshark]

15 hours ago, Ride365 said:

 

Synthetic isn't more slippery than conventional …..total old wives tale and oil folklore.  

I hear oil thread alarms going off somewhere. 😅 Just relaying what the dealer told me 2 days ago. Not saying he is right. He does not recommend full synthetic for this engine and he's a stickler for following Yamaha guidelines. He gave me a complete technical explanation that I can’t remember 100% so I won’t write it down.

But your point suits me. If different oil types shouldn’t make a difference to the clutch response when the oil is cold and @Manxkiwi has no resistance while I have a lot I may finally have a clear clue to what is going on.

I've gone ahead and created a poll to get more data.

 

Edited March 9, 2021 by petshark
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[Ride365]

If I had a dollar for every bad piece of advice that a dealer service rep gave us riders/owners, I would be a very wealthy man and could retire. 

[petshark]

So that poll is a dead end. Most bikes have the same clutch resistance so it’s no indicator that there is anything wrong.

Does anyone recognises the “bang” I describe above? If that is normal too it would put my mind at ease.