Clutch Noise.

[steven]

Hi,
I started up my 4L0 tonight for the first time after its rebuild.
I had given it a couple of quick runs with no radiator on for a minute or two, just to make sure it started.
It now has coolant in it and is all ready for its mot.
I noticed a bit of a rumble from the clutch, which disappears when you pull the clutch lever.
It has a new center steel bush, but not the sintered bronze bush, plates are all ok.
I have a few clutches, and used the best one I had, and the backlash figure is spot on.
It has all new genuine Yamaha damper rings fitted.
As I was doing a few heat cycles I noticed that the clutch noise actually got less as the engine warmed up.
All the gears engage fine, and finding neutral is not a problem.
I have just trawled through all the posts I can find regarding this, and it seems to be a common problem.
I have got Halfords 10/40 part synthetic 4 stroke motorcycle oil in the gearbox, I'm sure I read somewhere that putting a slightly heavier gearbox oil in seems to quieten it down a bit, but I cant find the post.
Can anyone comment on whether a slightly heavier oil may help?
If it comes to it I will pull the side casing off, get a billet basket and new sintered bronze bush etc, but I would much rather just put some slightly heavier oil in.
thanks in advance for any replies.
steven.

[Delbert]

Hi
I use comma 75/90 gl5 semi syn in mine & found it a lot quieter & smoother with out any problems with clutch slip

[steven]

hi delbert, thanks for the reply, was yours noisy too with "standard" oil in it?
I'm just reluctant to pull the casing off, again, but i will if i have to.
iv discovered that once you paint or powder coat something, taking it back off and on a few times usually ends up with it covered in spanner rash or chipped paint or scratches or something.
i bought a new billet basket ages ago, but i decided not to use it, as i did not like the idea of 4 off m6 screws holding it all together.
i looked into using normal cap screws and lock wiring them, but there is not enough clearance behind the clutch to do this, so it would just have to be locktite and nothing else.
I'm sure someone will be able to tell us that the shear load or whatever its called on 4 m6 bolts will be more than enough to take the load/torque, but I'm sure that every time my front wheel was in the air, id be thinking "those 4 m6 screws are going to shear"........or come loose or something,,,, so i just shoved it in a drawer and used my best "old" clutch basket, going on the assumption that the one with the least wear in the damper rubbers, will have done the least miles???
iv also read of people replacing the sintered bronze bush etc and the noise still being the same, anyway...... i might try some heavier oil and see what happens, but i fear I'm just postponing the inevitable, and ill have to pull the casing back off for a wee look..... i could have done it in the time iv sat here typing all this waffle
steven.

[Bozzy]

my 31k had a new billet basket and changed the centre bush to copper one to take play out but in fact I found the play still there. Had to take out the dampers as I fitted upgraded plates. had no backlash in the basket. but It rumbles and rattles quite a bit but now got used to it.

At one time it was quiet just think its character! good thing it does not slip.

My suggestion is unless is realy sounds very bad like its going to explode if it works ok leave it.

[Delbert]

hi Steven you sound much like me as in you like things right but
I have to agree with bossy ,, unless it sounds like it might exploded I would leave it .
I spent forever chasing a noise around , casing on off etc. changing baskets & the like & it was never quiet although it didnt alter by pulling the clutch in . I did find the thicker oil certainly helps .. My motors at its quietest around 6000 rpm. So thats the answer ;D

[steven]

hi, thanks for the replies, ill give the oil a go first and see what happens.
iv had a few LC,s over the years, but its been a while since iv heard one running close up, i just dont ever remember any untoward clutch type noises/grumbles in the past...mabey im just listening to it through rose tinted.....ears

[steven]

Hi, Last night when i was doing the heat cycles, and hearing noises from my clutch... the bike was on the centre stand.
As I was going up and down the gears while the engine was heating up, the back wheel was obviously spinning, with the engine revs at more or less tick over revs, this was when i was hearing the noise, and it went away when i pulled in the clutch.
If you put the bike in top gear and rock the back wheel back and forward, there is the combination of the play in the rear wheel cush drive rubbers, the gears in the gearbox, the play in the clutch basket dampers and the play in the primary drive.On there own these components I would say are within tolerance, but added together, this equates to a fair bit of backlash at the back wheel.
I notice that sometimes the momentum of the back wheel spinning forward when it was running, seemed to take up all the backlash in the various components, and make the noise.
I took the bike off the centre stand and started it on the side stand tonight and did another heat cycle....i am delighted to report that there is no noise, there is a VERY slight noise when its cold, that disappears as it heats up.
any thoughts on this theory? does anyone elses clunk a bit when running at tick over on the centre stand....
steven.
PS...can anyone remind me what is "normal" on the temp gauge? is it the first "notch" or the second one? or is normal between the two?
PPS, i re-torqued the head today also after 3 heat cycles, and got about an eighth of a turn on each head bolt.
thanks again for the replies.

[marsbar350]

hi steven
mine runs most of the time at the first notch.heats up a bit in traffic
the 1/8th turn for the head is pretty much what i had aswell
seems youve got it all sorted ;D

[Delbert]

Does the centre stand touch the exhausts when in use ?

[steven]

hi, no the centre stand doesnt touch the exhausts, they are standard exhausts.