Clutch questions

[Guest]

'79 GS 850, 39,000 miles.

My clutch slips pretty badly between gears if I'm really jumping on it, so it needs some work.

My question is how would one determine if its just the springs that need replacing, or clutch plates or pressure plates.....or maybe its best to just do it all.

I've taken the clutch apart on my practice motor, doesn't seem to hard to work on....

I just don't know how to evaluate what needs replacing or what my options are....stock, aftermarket etc. Any help would be appreciated.

Thanks.

[rrsteve]

If you're going into the case might as well do the whole enchilada... Buy a gasket, new springs ( I ended up with Beckett springs although I ordered "normal" springs)and friction plates. I reused the "steels" and everything is fine. Maybe slightly stiffer clutch lever due to Beckett springs, but not too bad. Definitely no more slippage. I fell for the "use motorcycle only" argument, modern (my bike is a '78 GS750E) oil may have friction modifiers not present in '78 style oils leading to clutch slippage.

[mark]

Thanks, I guess I knew I should buy everything. Might as well buy the bolts too, it seems that some folks are breaking them pretty easily. I can't tell by looking at the schematic how many friction plates to buy, guess I'll have to take it apart first and see.

[Road_Clam]

Generally speaking the springs loose "free height". there is a spec (my 1100's spring spec was 1.5") If you are close to this spec, toss the springs in the trash. My new springs measured 1.75". I thought my fiber plates were bad, but in hindsight my plates were only .006" under the "new" spec, and well within spec. I replaced them anyway, as I had the whole clutch apart and my bike had 17K for milage. I have Barnett fiber plates, and a fresh set of factory Suzuki springs, and I also had to replace the large bronze thrust washer behind the clutch basket. Now my clutch action is perfect. Before, accelerating up to 7500 rpm's would be fine, than all of a sudden my engine would violently overrev.

[Redman]

Mark,

Some comments from my two clutch replacments:
- clutch plates are sold in a kit, includes how many you need.
- manual states a service limit for the clutch friction plates in terms of the thickness of the plate (includiung friction material). I have found that the clutch can be slippping more due the friction material getting hard/brittle than the fact that it is worn down.
-manual also states a service limit of the springs, in terms of the free length of the spring removed out loose. My experince is that if the clutch is old enough to need replacing then might as well do springs also (unless replacing clutch due to abuse and springs are realtivly new.) Basically if springs are original or 10-15 years old, might as well replace them too. Unless you want to take apart to check springs then wait to get the replacments.
- When I replaced the clutch plates and springs, I realized that the clutch has been slipping much more than I realized - both times. Almost like I have to operate the clutch much different than I had been, because it then fuctions so different - better, like getting a new bike for $150.

.

[mark]

This is really helpful. I found a Barnett dealer so I think I'll get those plates....rest of the stuff OEM probably. Info on the sight goes in my 3 ring binder as usual.

[Redman]

Here, I'll look up a few things in the microfische:

- Drive plates (with friction material), Qty 8

- Driven plates ("steels"), Qty 8

- Springs, Qty 6

And from the manual:

- Drive plate thickness: 0.106- 0.114, service limit 0.094

- Spring Free length: 1.59", service limit 1.53
Hum, now I am not certain if spring is worn out if greater than or if less than thsi limit. Wording in Zuki manul doesnt specifically say.

[RacingJake]

Stick with oem Suzuki, Barnett fiber's will cause all sorts of problems.