clutch slipping

[Jon Burke]

81 GS850G. I'm experiencing clutch slippage in 3rd and higher gears under medium to heavy acceleration. Slippage seems lessened after riding 10 to 15 miles. Have been riding in weather that is in upper 30's to low 40's. That's all we have here in Michigan this time of year. Have adjusted the clutch cable per service manual. Am I overlooking something, or is the next step clutch disks and springs?

[Steve]

I'll bet you could go half way and be happy with the results. Chances are that you will only need springs (and a gasket). They are cheaper than the disks, too. 8-[

One other thing to check ... make sure you are NOT using oil that is marked "Energy Conserving" in the API seal on the back. They have friction modfiers that, well, they modify friction, which really upsets what a clutch is supposed to do. Fortunately, most of those oils are 30w and thinner. I have not seen any 10w-40 or 20w-50 oils with that designation.

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[Jon Burke]

I'll have to check on the oil. I'm using Suzuki 10w40 oil. Would think it's correct for a wet clutch. I'll have to read the back of the jug. The clutch springs weren't too bad. Didn't think about just doing the springs. If it didn't work and i had to replace disks later, would only be out the gasket. Might have to source some SS allen head screws to replace the philips while i've got the cover off.

[tkent02]

Springs WILL fail with time they are compressed at all times and will eventually lose their tension, plates only wear with use, or abuse.
Replace the springs, measure the plates, specs are in the manuals.
Mostly the plates are fine unless you bike has had it's clutch slipped a lot.

[Steve]

I agree with you, I would think that Suzuki would supply the correct oil, but as mentioned, I have not seen a 10w-40 with the EC rating.

The springs may not seem to be bad, but have you measured them? I am in the process of getting my son's 850 going. The bike was a "daily driver until parked" last fall. I have heard it run, but not well, and have not used it to move itself, not even in the driveway, so I have no idea if the clutch slips or not. However, we removed the clutch cover to polish it, and I am trying to teach my son about the inner workings of his bike, so I said "let's check the condition of the clutch" and we proceeded to measure the plates and springs. The plates are all near the upper end of specified thickness. (This is on a bike with 34,638 miles showing on the odometer.) The springs have a specified length of 40.4mm with a service limit of 38.8mm. Ours are all right near 38.0mm, which is about 2.5mm shorter than they should be. It is possible to apply a 'band-aid' and shim them with washers, but they are relatively inexpensive. I found the best price ($2.12 each) at Motogrid, but most of the other suppliers were not much more: Flatout, 2.19; Parts-n-More, 2.67; Bike Bandit 2.71; Babbits, 2.97. Alpha Powersports, at $3.66 was the most expensive one that I saw. You will need 6 of these little guys and your gasket and you will be set.

Just for your education, the price for the friction disks ranged from $6.00 at Partsnmore to $15.02 at Alpha, and you need eight of them.
Doing the math here, it will be $48-120 for disks or $13-22 for springs. Your choice.

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[Jon Burke]

This bike was also a daily driver, but parked 8 years ago. Bought Labor day last year and have been working the kinks out. So far, lined tank, new fuel petcock, carbs cleaned, intake boot o-rings, spedo cable, grips, oh yeah, new pair of avons last fall too. It's got 23k on the odometer. You're probably right about the springs being out of spec. I'll pull the cover and check. Might as well put them in if i've got it apart to check it.

[Dogma]

Don't forget to use a torque wrench on the clutch spring screws (they're pretty cheap at Harbor Freight). The screws uh, pop off too easily. It's all but impossible to feel them tighten correctly with the spring load on them, and the torque spec is pretty low anyway. I read somewhere that these screws also have a special heat treat on them. I don't remember which manual said that. I went ahead and replaced all six with OEM parts when I got my springs. They're also pretty cheap.

[Steve]

I know that someone has been inside the clutch cover at some time in the past on our bike.
One of the clutch bolts has the right threads, but only has an 8mm head, where the rest of them are 10mm. :shock:

Since we are going to be ordering one, we might just as well order the other five, too. Thanks for the tip, Dogma.

[Dogma]

Hah! I figured you knew all that and forgot to mention it to Jon! I just posted it because I wanted to make him aware of that particular mistake I made, and the time penalty on the project.

OT: How on Earth am I a senior member already?

[bwringer]

All you need is new OEM springs. The clutch disks last almost forever in these things.

Springs are about $2 each. Add in a new clutch cover gasket, and you're looking at a $20-$25 repair and 30 minutes of time, if you're slow.

Put it on the kickstand, and you won't even need to drain the oil.

Easy-peasy.

[Steve]

How on Earth am I a senior member already?

Happens to motor-mouths quicker than others. 8-[

You achieve that 'status' when you have 100 posts to your credit.

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