Vibration While Letting Clutch Out

[John d]

The only way to determine is by the symptoms you describe. That bearing is always inactive except when the clutch is activated. A worn out clutch bearing would cause the pressure plate to vibrate when the clutch is released. The bearing itself is probably a cheap low speed bearing that you could find at any bearing supply shop. I'm not sure if the bearing is pressed in or not, but that is likely.

I'm going on theory and the fact that I don't have a second guess.

 

[RossKean]

With the clutch lever pulled all the way, there is no vibration. With the lever fully released (in neutral) there is no vibration. It is only from the time the lever is fully pulled in to perhaps 1/3 of the way out and only in gear.

 

[John d]

I still think it's the bearing.

You can do the clutch bleed first, I doubt it will make a difference, but at least it's cheap and fast and you may be due anyway. An oil change can't fix your problem.

 

[RossKean]

Thank you for this contribution. I will report back when I know more (possibly not until the weekend).

 

[Mihalis fjr]

My Gen 1 does the same thing for many years.I mean does the same thing,vibrations ''while letting clutch out'' about at 1/3 out.

I think that it caused from dry plates.When i did an oil clutch bath the problem dissapeared for some km,about 2-3000.

Then the problem came back...

 

[Fred W]

My first guess would be a worn out clutch bearing - Part 15 in the diagram.

Will do the oil and hydraulic fluid first. Next stop is to open the clutch to examine the guts. Any way to determine a bad bearing short of dismantling to that point?

I've had bad throw-out bearings on manual transmission cars several times in the past. The principle is the same as the thrust bearing on the back side of the pressure plate of a motorcycle clutch. When the throw-out / thrust bearing is bad it would vibrate strongest when the clutch lever is fully pulled in and holding the clutch fully disengaged against the pressure plate spring. You would get vibration in the pedal or lever in that state.

Your symptom (the one that I have felt before, and what seems somewhat common on FJRs from several reports now) is only happening when the clutch is partially disengaged (or as the optimist would say, partially engaged). This indicates that it has something to do with the slipping action of the clutch's friction discs against the steel plates.

A change in oil may affect that friction and slipping for the better (or worse?). If not for the better, my next action would be to disassemble to do a clutch soak and closely scrutinize all of the clutch plates, and also the friction surfaces of the clutch basket and pressure plate, for any surface wear or patterns.

Edit - It just occurred to me that the symptom I remember on my '05, which I never did resolve, was always most noticeable when the engine was cold. Is that true on yours? If so, that may give even more credence to the idea of the oil change helping.

 

[Constant Mesh]

Remember, this bearing is not turning when you're sitting still in gear with the clutch lever pulled in. The pressure plate is splined to the transmission input shaft via the clutch boss. On a car the pressure plate is attached to the crankshaft so it always turns at engine speed. On the FJR when you're in gear but not moving the release bearing is not turning.

When you're in neutral with the engine idling and the clutch lever released the transmission input shaft is turning at engine speed. When you pull the clutch lever now the bearing spins at idle rpm. But it spins slower and slower as the input shaft comes to a stop with the clutch disengaged.

 

[RossKean]

My first guess would be a worn out clutch bearing - Part 15 in the diagram.

Will do the oil and hydraulic fluid first. Next stop is to open the clutch to examine the guts. Any way to determine a bad bearing short of dismantling to that point?

Edit - It just occurred to me that the symptom I remember on my '05, which I never did resolve, was always most noticeable when the engine was cold. Is that true on yours? If so, that may give even more credence to the idea of the oil change helping.

Probably a little worse when cold but doesn't goes away when the engine heats up. Again, it isn't awful but it isn't normal and I want to address it before it gets bad. Maybe I can eliminate oil and clutch bleed tonight and save the surgery for the weekend...

 

[John d]

Remember, this bearing is not turning when you're sitting still in gear with the clutch lever pulled in. The pressure plate is splined to the transmission input shaft via the clutch boss. On a car the pressure plate is attached to the crankshaft so it always turns at engine speed. On the FJR when you're in gear but not moving the release bearing is not turning.
When you're in neutral with the engine idling and the clutch lever released the transmission input shaft is turning at engine speed. When you pull the clutch lever now the bearing spins at idle rpm. But it spins slower and slower as the input shaft comes to a stop with the clutch disengaged.

That makes my theory wrong. So it may not be the bearing.

 

[Fred W]

Remember, this bearing is not turning when you're sitting still in gear with the clutch lever pulled in. The pressure plate is splined to the transmission input shaft via the clutch boss. On a car the pressure plate is attached to the crankshaft so it always turns at engine speed. On the FJR when you're in gear but not moving the release bearing is not turning.
When you're in neutral with the engine idling and the clutch lever released the transmission input shaft is turning at engine speed. When you pull the clutch lever now the bearing spins at idle rpm. But it spins slower and slower as the input shaft comes to a stop with the clutch disengaged.

Good points. I missed that difference. That bearing will do very little rotating under any circumstances since the clutch boss is splined to the transmission input shaft and that is what is on either side of the bearing. Not even sure why they have a bearing in there.

 

[Constant Mesh]

Don't believe the long clutch push rod rotates. It appears to have a friction fit into the slave cylinder piston. At the end of the push rod is a large ball bearing which some have forgotten to re-install when working on their clutch. That ball is the transition device between the long push rod and the short push rod.

The short push rod is a bit mysterious. As you're riding down the road I don't know if the short push rod is spinning or motionless. The bearing outer race appears to be pressed into the pressure plate so it's always turning with the plate. Don't know how the short push rod interfaces with the bearing inner race? Are they essentially locked together or does the short push rod back away and lose contact when the lever is not pulled?

Maybe someone can study the behavior of the short push rod and explain how it works!

The bearing speed would appear to be highest when the transmission input shaft is turning at a high speed and you pull the lever to disengage the clutch.

 

[Fred W]

Short pushrod has an o-ring that fits in the bore through the transmission shaft, so it should be spinning at the same speed as the shaft. That's why I don't really know what the thrust bearing is there for.

 

[Mihalis fjr]

Repeated post,my fault..

 

[RossKean]

Oil change today and it MAY be a bit better. I only had Rotella 15W40 on hand but I figure there is probably an effectively greater difference between old oil and new oil than there is between new dino and new synthetic. The oil on the clutch plates doesn't exchange quickly so I'll give it 30 miles or so before I move on to the hydraulic fluid. (I will still do the hydraulic fluid but want to see if the engine oil was the main issue or not) Clutch bleed/flush next and open up the clutch as a last check disks etc. (but only if necessary). Stay tuned...

 

[RossKean]

Got it out for a half hour run. I would say there has been a 90% improvement. It is, perhaps, to the point where I might not notice it if I was not looking for it. It may get better or I may eventually have to see if Fred is still looking to unload his low mileage set of used disks from his '14. It is a high mileage clutch and having to replace wear items (friction disks) at this stage wouldn't be a surprise.

I checked my oil change records and I either forgot to write down the last one or I missed it! I was getting close to due for the next change, within the next week or so anyway. There is a possibility that this oil had 9,000 miles on it instead of 4,000. While that wouldn't disturb me if it was on a long highway trip, this was mostly short distance day trips last fall and this spring. (Normally, the oil would have been changed and recorded at 5,000 miles or within 1,000 miles of when the bike was going to be put away for the winter) Mind you, I have forgotten to write down maintenance stuff before and have had to add to the records with estimated mileage a week or two later. This shall remain a mystery.

I'll give it a couple of weeks (and do the hydraulic fluid too) before I call it cured. I have had old beater cars that told me when they needed fresh oil (noisy top end) so maybe the FJR can tell me when its time to change as well.

I will go back to synthetic after this.

 

[Harald]

If it makes you feel better, my 07 with 122,000 miles on it has done the shuddering clutch engagement a few times in the last year or two. It's always been on a cold engine IIRC and I've run Rotella 15w40 for the bikes whole life except for maybe a couple changes when I had another oil available. Due to the very intermittent occurrance, I've not bothered with any troubleshooting. I'll be interested to see your resolve in case mine gets worse.

 

[RossKean]

For now, I am attributing to oil combined with 166,000 miles. Do you recall if yours improves when you change oil?

If it stays better for a little wile and then starts to go "off" again, I will pull the clutch apart and have a look to see if the friction disks (or other stuff) need to be replaced. Perhaps it just prefers the synthetic oil I have been using for most of the bike's life (Rotella T6 5W40).

 

[Fred W]

My clutch engagement and shifting notchy-ness was not improved by Rotella T6. I think it was actually better with the Rotella T 15W40 conventional oil than it was with the T6. After switching to Mobil 1 15W50 because it was (and still is) less expensive than the Rotella T6 per quart, it was better still.

While doing an oil change is a good first indication, especially since you felt a difference, I'd encourage you to go ahead and try the Mobil 1. I'm sure that it isn't that hard for you to find even north of the border.

 

[RossKean]

Canadian Tire currently has the Mobil 1 on sale. I am planning on picking up a jug for the next change. You mentioned that you are running the 15W50 so I will try that. I think they have the M1-110 Mobil 1 filters on sale too.

Edit: Crap! They don't carry the 15W50. Walmart didn't have it either!

There is no question that most (but not all) of the shudder/vibration is gone.

 

[Harald]

I didn't notice if an oil change had any effect on the shuddering. It's not happened very often, so I haven't really investigated a fix.

Not that it would prove anything in my case, but the next couple oil changes will be with Mobile One 15w50 because the May rebate made it cheaper than my usual Rotella 15w40. This oil change will only tell me something if the problem reoccurs due to its intermittent nature.