Sunbeemer wrote:Holding the clutch lever in for a long time will tire your hand out and, I suspect, put more wear on the clutch slave-cylinder push-rod bearing, but it shouldn't wear the throw-out bearing since that is not spinning when the clutch is disengaged.
This IS the throw out bearing (although BMW doesn't call it that) or allows the shaft to spin when under pressure and will as long as the clutch lever is pulled in. When bearings spin there is wear.
Last edited by kirby on Thu Mar 01, 2018 8:34 am, edited 1 time in total.
The clutch plate is always spinning as long as the engine is running, engaged or not engaged!
When you let the clutch leaver out it just relieves the pressure on the shaft and the shaft will stop spinning. The plate is splined and slides onto the trans input shaft.
Thanks for the response, but I still don't understand...if the clutch plate is always spinning whenever the engine is running, and it is splined to the input shaft of the transmission, how do you disengage the clutch to shift gears?
If this is going too far afield of the original topic we can move it to another thread.
The clutch plate is pressed against the fly wheel by a pressure plate so that it doesn't slip when the clutch lever is not pulled in. This is the only connection between the transmission and the engine, in other words the splined input shaft is not connected to the engine, Its connection is only thru the clutch.
When you pull the clutch lever in, it hydraulically W/a piston presses a rod that runs thru the input shaft (hollow) and pressed against the pressure plate diagram (springs) and relieves the pressure on the plate and it allows the plate to slip and unloads the transmission.
The plate doesn't move but a fraction (tiny if at all) of an inch and really just relives the pressure on the plate that runs against the flywheel.
This is related to the op's question because holding the clutch leaver in while in gear does heat up the plate depending on how long its done, and puts pressure on the throw-out bearing.
Kirya - back in the days when these dry-clutch bikes were current models, Berlin-Spandau unequivocally advised AGAINST holding the bike in gear with the clutch lever held in, for longer than was absolutely necessary.
Despite kirby's comment that after 250K miles of slipping or holding-in a dry clutch in that manufacturer's unadvised way, he has no noticeable clutch wear ( not 'ware' ), the danger is that the pesky Clutch Slave Cylinder will go west sooner than it normally does. With the clutch lever held in, the actuating rod inside its tube has its rear end spinning in the slave cylinder's inadequate bearing at engine speed. Quickly leading in a few short years to collapse of the bearing, as witnessed by a brief Chis Harris graphic video.
Decades ago when I was a "schoolboy creeping reluctantly to school" ( Shakespeare ) one early Spring morning, I witnessed an unforgettable rear-end shunt to a motorbike.
A guy on a sparkling new Vincent HRD 'Black Shadow', the fastest and most costly production motorcycle available in the 1950s, was sitting astride his stationary mount at a red light just past a sharpish urban bend.
As I crossed the road in front of him with my little pals, reaching the far pavement, I saw, careering round the corner up to the lights, a battered old Bradford van. The driver's face showed his horror as - too late - he stood on his brake pedal and closed his eyes. Smacking the Vincent smartly in the rear and flirting it out from under its burly rider, who remained standing.
Without batting an eyelid under his pork-pie lid, the guy watched his precious mount topple gently to the ground 20 feet in front of him. Instead of stepping forward to pick it up, he turned back to the van, walked up to it, ripped the door open and dragged the driver forcibly out of his seat, smashing him in the face with one heavy blow, laying the guy out unconscious in the middle of the road.
He then calmly returned to his fallen steed, picked it up, swung his leg over and rode off.
During the entire incident, not a word was spoken.
I must not have made myself clear !?
"Despite kirby's comment that after 250K miles of slipping or holding-in a dry clutch in that manufacturer's unadvised way, he has no noticeable clutch wear ( not 'ware' " .
Sykospain quote.
Thanks for the correction, I didn't catch that, must have been the auto correct
Post by kirby » Mon Feb 26, 2018 7:35 pm
Probably not if you only do it on hills, not often no?
I always go to neutral a when stopped for more a few seconds. I figure if someone is coming up fast behind you, depending on their closing speed, being in gear won't do you any good, more likely to panic and stall the engine.
Almost all my vehicles have have standard transmissions w/dry plate clutch same as the beemer, and I ALWAYS shift to neutral when stopped at a traffic light or when standing.
I have never had to replace a clutch on any of my vehicles used for normal ops.
Yes kirby I definitely think that's the method to adopt - knock into neutral and leave the clutch lever alone whenever you're at a stop.
The issue about being rear-ended while stationary, like the tale of the Vincent Black Shadow rider, seems to me to be one of those possibilities that doesn't negate the approved method with a dry clutch of trying to avoid any unnecessary clutch-lever-held-in whilst in gear situations.
The adviseability is well-documented for these dry clutch vehicles.
As guru Chris Harris has said very often in the past, use the clutch lever like a switch - in or out as fast as you can conveniently manage. That method most certainly prolongs the life of your transmission.
Incidentally, I notice that some Spares people have now run out of stock of the Thailand-made longer-hub friction plate that beats the old OEM Sachs plate hands-down. At least Moto-Bins in the snowy London area has recently commissioned a new batch from Italy of all places.
Yeah, when I did my first separation on the rockster I had bought a new plate just in case. With 169K on the clock the plate (original) measured .290 and the new (OEM) plate was .310 so I did not replace!
Some folks just have to ride the clutch in autos or bikes and hold when stopped. pity
Our MSF instructors are the blame here in the states by telling the beginners and the old hands alike to stay in gear. Duh!
Where are you supposed to go if you detect an oncoming vehicle? Unless you the first in line there is no place to go, and if you bolt out into an intersection!!
Just back from two weeks in Austria skiing. Fun!
Where are you supposed to go if you detect an oncoming vehicle? Unless you the first in line there is no place to go, and if you bolt out into an intersection!!
You know Kirby, not all old-timers necessarily agree with you! I am preparing to sign up of Social Security soon myself and I still contend, all clutch wear issues aside, that there are usually some escape paths available and being aware of them is part of my riding routine. Both stopped at lights and on the interstate for that matter. Actually, on the interstate, I do that driving the cage too!
You might call it paranoid but I just call it being prepared. There are enough inattentive drivers on the road. I try not to add to the number.
That said, I do go into neutral as soon as I have a couple of vehicles behind. Only takes one, it its a big one!
'02 in black - the real BMW color! (Now gone to a new home)
Vann - Lifer No. 295
With the powered brakes it's easy to hold the bike stationary on a hill, in neutral, on the front brake. And my hand does get tired holding the clutch lever for more than a few seconds. I've rarely stalled doing hill starts and it doesn't seem onerous to engage gear and let the clutch in while letting the front brake off.
That whining of the brakes really gets my goat though.
