Check clutch slip

[roeme]

I recently had my clutch slipping on the highway, after I switched gears for an overtake maneuver. The bike took a long time until the clutch properly "grabbed". I actuated the clutch quite quickly, road was slightly uphill. Can't remember for sure how far I let the rpm's dip and how well load/selected gear/rpm was matched (the tach has the well-known problem displaying high rpms), but it all seemed a bit too slippery. The clutch cable is adjusted to disengage/engage "late" (maybe gotta check the screw gear as well).

I have new plates and springs in storage, but how do I verify beforehand whether I need to replace them at all? Do I need to open her up and measure anyway?

Bike has ~35k km, bought and "rebuilt" it a few hundred km's ago.

 

[Redman]

Do you need to measure?
Yes and no.

You know it is slipping under this certain condition. I suspect is slipping some under other conditions, just that it not as noticable. Or that was my expereince. I noticed slipiiing under some situations. I replaced the clutch friction plates....and... oh, man... what a differnce.

Measure? Yes and No.
Manuaul will list service limits for thickness of the clutch plates, and yes, if less than that will need to be replaced. But if not less than that, I say still needs to be replaced because you know is slipping so the frction material is hardnended.
Manaul also list service limits for the spring "free length". If springs are worn out the "free length" goes longer, so if the "free lenght" exceeds the spec, then yes they need to be replaced.

Other thought: If clutch friction plates and the springs are still original, Yah, the probably need to be replaced.

.,

 

[Guest]

loads of info here, but, if it were me, I would do the springs first and see if that fixes things. Easy enough to go back in after the plates if it is still no good, like 6 bolts and a cheap gasket. I wouldn't even take the clutch pack apart to measure without trying this first. But.....i am pretty lazy....

 

[roeme]

I just went for a short jaunt, and had noticeable slippage when cold and/or uphill after shifting. Interestingly enough, the yank whenever the clutch grabs again varies a lot; sometimes it's obvious, sometimes it's hardly noticeable.

I'm gonna dig in. Since I had the oil changed just a few kms ago, in order to keep oil lost to a minimum, you reckon I can tip the bike to it's side for that? (Sidestand is currently not on the bike for various reasons)

 

[Guest]

Since I had the oil changed just a few kms ago, in order to keep oil lost to a minimum, you reckon I can tip the bike to it's side for that?

Dirtbikes have clutch covers pulled like this all the time to prevent oil spillage and it works fine. Can't see why not on your GS. Put a piece of wood or something under the bar to support it and watch out for fuel leaks.


Mark

 

[Cipher]

follow the oem manual and adjust your clutch.

 

[Gorminrider]

I have new plates and springs in storage, but how do I verify beforehand whether I need to replace them at all?

That's a question to ask BEFORE buying new parts but:
First see Cipher's^
But my first thought was:
You've got new parts! Why not enjoy them? what are you saving them for? the day your clutch needs work? That's now... and why worry about "oil loss" and tilting the bike yadayada? Drain the oil, put new parts in. Clutches are pretty easy. Save the old ones for spares if they have any life in them . Check your cable while you're at it.

 

[Guest]

if it only slips right after shifting ....
check if your clutch cable is seizing ( or lever worn out)
it should be practically friction free when disconnected from lever and clutch arm

 

[roeme]

Clutch has been replaced, found the drive plates still in spec (2.9mm), as the springs (measurement not handy at the moment). Now clutch is super grabby, but the issue still persists somewhat.
The gremlin must be somewhere else. Doing that in a different thread though.

 

[roeme]

Clutch has been replaced, found the drive plates still in spec (2.9mm), as the springs (measurement not handy at the moment). Now clutch is super grabby, but the issue still persists somewhat.
The gremlin must be somewhere else. Doing that in a different thread though.

...creating another thread has become moot. I've since tracked down the issue to bad contacts on the primary side of one coil. Built a replacement cable which connects the coil to the wiring harness, and the bike pulls very well since. No pictures unfortunately.

 

[Gorminrider]

aha! I bet that feels g-o-o-d!, especially as it's so far off the beaten path per a feel of "clutch slip" ... must be just a little surge gives the bad wire a wiggle ?

 

[roeme]

aha! I bet that feels g-o-o-d!, especially as it's so far off the beaten path per a feel of "clutch slip" ... must be just a little surge gives the bad wire a wiggle ?

You bet. Much joy was expressed under the helmet on the ride home.

It's quite a chunk added to my personal knowledge about these bikes. The aforementioned clutch slip did feel a little bit weird for that, as it didn't properly correspond to load, but rather a mixture of rpm (= current on primary side of the coil plus vibration) and ride situation (= vibration plus bad contacts killing current carrying capacity). Of course, as I'm a comparably novice rider, I couldn't diagnose this right off the bat, though the issue wasn't easily reproduced to begin with. Those are always a b!tch to track down...

 

[Chuck78]

Clutch slip on highway would feel like the bike is revving up all of the sudden when you really get on the throttle. You will experience it at highway speeds more than anywhere else due to the extreme amount of force the wind resistance has against the bike. This is more force than a spirited take-off from a stop, in my experiences with clutch slippage. A weak spark would not allow the engine to rev up as if it was in neutral (sorta), it would just not accelerate or rev up/ Clutch slippage at highway speeds would give you the engine revving up but no acceleration taking place.

The first big thing I thought here was this - YOU JUST CHANGED YOUR OIL! What oil did you use? Is it approved for wet clutches? has the manufacturer changed the oil additives formula since the last batch of this oil that you used?????
Secondly, where I think my issue was with this same problem - did your carbs flood, resulting in oil getting into the gas? A faulty petcock or one left in the prime position with the bike parked will end up dumping some gas down into the cylinders, which will make it's way past the piston rings and into the oil pretty readily, and GAS IN OIL will do the exact same thing as Energy Conserving / Resource Conserving automobile rated oil on a wet clutch - it will get into your friction linings and make your wet clutches slip badly under the heaviest loads!!!

When replacing the springs, the EBC "10% stronger than stock" springs feel like 60% stronger than stock, and it is commonplace to only replace every other OEM spring with the EBC aftermarket stiffer springs in order to not have a ridiculously tough to pull clutch lever... FYI. Perhaps it was advertised 15% stronger? It is a SUBSTANTIAL difference, whatever they claim, feels like far more spring at the lever than before, and uncomfortable to pull.