Clutch problems

[erik]

The bandit isn't changing gear nicely, it's sticky and clunky. Finding neutral when stopped can be a pain. It gets worse when it's hot. With the bike on the centrestand and in gear, when the clutch is pulled in there's still quite a bit of force turning the back wheel, not enough to make the bike roll forwards when it's on its wheels, but enough that I've got to apply a fair bit of force to stop the wheel from spinning when it's on the centrestand. It changes gear smoothly if the rear wheel is allowed to spin with the bike on the centrestand.

I've had the clutch apart a couple times, measured the thickness of the friction plates, they're all within spec. Checked the steels for warping on the granite benchtop, 2 were warped and one was maybe, so I replaced the 3 plates. It seemed to help a bit maybe, but it's still dragging. I haven't checked the friction plates for warping, the manual doesn't mention checking them and as I understand it it's the steels that warp.
I think the bike has overheated a bit in the past, I've had to fix the radiator fan and replace the thermo switches, I don't know what that might've done to the clutch.

Could the other steel plates still warp when they get hot even if they're perfectly flat when at room temp? Should I replace them too?
Do friction plates get more draggy if they've been overheated?

I was worrying for a while that the clutch might not be getting enough oil because the friction plates looked fairly dry when I pulled it apart, but when the engine is running and the oil cap is off, a decent amount of oil is being flung off the clutch. Plus I pulled it apart and pulled the sump off and checked the oil pump pickup filter and couldn't see anything wrong.

I'd rather not throw money at it for new clutch plates if that's not going to fix it, but I really need to get this sorted. I'm getting a sore clutch hand after riding for a couple of hours, I think it's from holding the clutch open slightly longer than normal during gear changes to try and get them smooth because it's dragging. After the last ride I did down SH22 my hand was so sore I had to try to operate the clutch by pulling the lever back with the palm of my hand which was a bit of fun trying to get away from the lights smoothly, but I'd rather not have to do it again.

[98tls]

Does it have a worm drive to adjust clutch pushrod........?

[98tls]

Just a thought......when installing new plates/steels on a TLS the last plate in is off-set a notch to all the others......if you dont do it clutch doesnt work properly......not sure if its the same on your bike etc........just thinking if it is the same you may have missed that when putting it back together

[Paul in NZ]

To check your steel plates place them all togther in a stack and look through them edge on towards a strong light source - you will soon see if they are warped.

Careful adjustment of the clutch with the cable slacked off is the go...

Cheers

[T.W.R]

Just had a look at a schematics diagram for the GSF400 clutch assembly

Couple of questions:

1) Is the washer that sits between the inner hub and outer basket in place? is it there at all?

2) The screw on the screw assembly adjusted properly with the right amount of free play?

3) Between the inner most friction plate & hub there is supposed to be a wave washer (ring same diameter as friction plates) and a wave washer seat (same size) are they in place? and the right way around (seat against the hub then washer & the 1st friction plate) ?

[T.W.R]

Here's a link to the schematic diagram, so you can see what I'm talking about

http://alpha-sports.com/spst/1993%20GSF400/07.htm

[erik]

It's got a worm drive and I've tried adjusting it as the manual suggests, the clutch outer plate moves about 2mm which should be heaps, the clutch doesn't engage fully till the lever is near the end of it's travel when releasing, which I think might be contributing to my sore hand, so I've given the cable a bit more slack and will see if that helps my hand.

The manual doesn't mention anything about notches. There's a thin cork plate and a washer and spring washer on the inner side, then 5 paper plates, then a thicker cork plate on the outer side of the clutch. Looking at the photo below, there's a notch in the inner cork plate but I can't see if there are or aren't any in the other plates.

I forgot to say, I read (Kwaka Kid posted it ages ago) that blipping the throttle can help when trying to get it into neutral and that if it does, it might mean the carbs need to be balanced. I don't understand how the carb balance would affect it unless it's similar to how twins and big bang inline 4's get better grip in the wet than standard inline 4's. So that's something I should check tomorrow, but I think there's got to be more wrong than just the carb balance.

[erik]

To check your steel plates place them all togther in a stack and look through them edge on towards a strong light source - you will soon see if they are warped.

Careful adjustment of the clutch with the cable slacked off is the go...

Cheers

I checked them on the granite benchtop by trying to slide a .1mm feeler gauge underneath them at several places around it, like in the manual (except they say use a surface plate instead of a granite benchtop).

I'm thinking I might pull it apart for a 3rd time tomorrow and check it your way.

Just had a look at a schematics diagram for the GSF400 clutch assembly

Couple of questions:

1) Is the washer that sits between the inner hub and outer basket in place? is it there at all?

2) The screw on the screw assembly adjusted properly with the right amount of free play?

3) Between the inner most friction plate & hub there is supposed to be a wave washer (ring same diameter as friction plates) and a wave washer seat (same size) are they in place? and the right way around (seat against the hub then washer & the 1st friction plate) ?

1: Yes, it's there. See additional photos below.

2: yep, it was adjusted correctly. just today I've tried giving it a little extra free play to make the clutch engage with the lever closer to the handlebar. This doesn't seem to affect the clutch drag.

3: yes they're there. it's not a wave washer, it's a sort of conical spring washer, but it's there.

[erik]

I just went and did some testing, took the bike for a short ride to warm it up.

When the bike is cold, the clutch doesn't drag much at all. It's easy to find neutral when stopped and there's very little force on the wheel when it's in 1st with the clutch in.

I let the bike idle for a bit, the radiator felt warm, but the clutch still seemed not too bad, not too much dragging. So I took it for a bit of a ride to get it warmed up. The fan thermo switch comes on around 95°C and the fan came on a for a bit when I stopped.
Stopped with the bike warm, it's impossible to find neutral or even get it out of first (well, maybe if I really stomped on the pedal but I don't want to try that).
But, blipping the throttle works like a charm to help it change into neutral. Even holding the bike at slightly higher revs (approx 3000-4000rpm) helped it change gear, although with much more of a clunk when going from neutral into first since it's spinning faster.
Also, with the bike on the centrestand in first gear with the clutch in, giving it some revs reduced the force required to stop the rear wheel spinning.

So it seems there's two things happening:

1. As the bike heats up, the clutch drag gets worse.

2. With higher revs, the clutch drag is reduced.


I don't think the carbs could be that out of balance, I know I've balanced them before, a few months ago I think. Anyway, I'm still skeptical that the carb balance or lack of it could cause the revs to affect the clutch drag that much. But I should check it tomorrow anyway.

Whether the carbs are out of balance or not, I guess either the steels (or friction plates?) must be warping with the heat for it to be ok when cold and dragging when hot? The oil isn't going to be affected by heat enough to cause that kind of difference, right? (it's silkolene semi synthetic 10w40)

[Kwaka14]

Try a different brand of 4t oil (I went from motul to mobil 1 4t and it made the changes smoother straight away) and make sure the chain tension is correct, too much slack makes for clunky changes and a hard time finding neutral as things jump around a bit sometimes..

[T.W.R]

1: Yes, it's there. See additional photos below.

2: yep, it was adjusted correctly. just today I've tried giving it a little extra free play to make the clutch engage with the lever closer to the handlebar. This doesn't seem to affect the clutch drag.

3: yes they're there. it's not a wave washer, it's a sort of conical spring washer, but it's there.

Ok, well going by a fault diagnosis chart and what you've described it leaves possibilities of:

Clutch spring issues (uneven tension, sagged springs, or broken)
Engine oil (deteriorated, or viscosity too high (too heavy))
Clutch housing binding on the shaft
A defective release mechanism
Loose hub nut

Looking at the pics you've posted the oil residue in the casings does look very tarnished. what's the oil smell like? sweet or burnt.

[sAsLEX]

Looking at the pics you've posted the oil residue in the casings does look very tarnished. what's the oil smell like? sweet or burnt.

Just drop the oil and filter and do a change, aint going to hurt anything doing it a bit sooner!

[erik]

pulled it apart again today. The steel plates look ok. The innermost friction plate might be a tiny bit warped, it's hard to tell. I checked the carb balance, it's as good as I can get it.

The clutch springs are all within about .1mm of eachother in length. The clutch hub nut was actually loose the first time I pulled the clutch apart several months ago, but I've since tightened it. I think the release mechanism and housing are ok.

The discoloured engine casings is I think from when the thermoswitches and fan weren't working, it must've overheated the oil that was in it at the time.

I think I'll try a different brand of oil and new filter. It's only at about 3000k's since the last change (and less than 6 months).

One good thing I realised I could change the clutch plates without draining the oil by tipping the bike a bit further over by putting a block under the front wheel with it on it's side stand.

[erik]

The "clutch problem" is sorted!

All it took was changing to a different brand of oil. I was running Silkolene 10w40 semi synthetic and assumed it was reasonably good stuff. Mark at Mt Eden Motorcycles suggested I try the repsol 15w50 mineral oil 'cause he reckoned it helped his bike and what do you know, it worked! The gear changes and finding neutral are much improved.

My hand is still getting sore from using the clutch though. I'm starting to wonder if my dririder nordic gloves might be the problem, too much padding?...

[FilthyLuka]

My hand is still getting sore from using the clutch though. I'm starting to wonder if my dririder nordic gloves might be the problem, too much padding?...

lube your clutch cable