Slipping/worn clutch help

prudolph · April 12, 2009, 08:02:05 PM

Hope everyone had a nice holiday,

So I think im having problems with my clutch. Had a long ride today and noticed my clutch was slipping. After about 20 mins into the ride I go to do a take off and after fully engaging the clutch the engine is still reving high then comes back down. Felt as if I was holding the clutch lever in like halfway. So, later on I crank the throttle doing about 50~ and it revs up and has a similar effect as if i were holding in the clutch but i wasn't.

Im on a 03 M620 (wet clutch) with about 12.5K miles. i picked it up fall 08, im not sure when/if the prev. owner had any thing done to it.

Ive searched around a bit and found info about the springs being weak.

So my main questions are:

How to diagnose that it is the clutch and not something else?
What parts am I going to need ( I already have the plates from the previous owner)? I am pretty set on doing the work myself.
is there any tutorial on a changing a wet clutch that i have missed?

Thanks in advance guys and gals.

ducpainter · April 12, 2009, 08:08:13 PM

Have you done any mods recently...like different levers?

prudolph · April 12, 2009, 08:16:32 PM

nope, no mods

everything is stock to the best of my knowledge.

ducpainter · April 12, 2009, 09:25:19 PM

Just checking.

The symptoms you describe pretty much point to the clutch itself.

If you used car oil the problem could be friction modifiers in the oil. If you had changed levers it could be that the bleed back was adjusted incorrectly.

Assuming you didn't use car (energy conserving) oil, it is probably the plates. Once they start slipping it would be easiest and least time consuming to replace since you have new ones already.

Make sure you soak the new plates in oil before installing.

prudolph · April 12, 2009, 09:52:41 PM

I think my problem is the oil, i recently did an oil change and was told car oil would be fine.(guess not) Oh well, live and learn.
So, are my clutch plates doomed or can i revive them by switching out the oil?

Howie · April 12, 2009, 09:58:45 PM

Quote from: drenalinejunki92 on April 12, 2009, 09:52:41 PM
I think my problem is the oil, i recently did an oil change and was told car oil would be fine.(guess not) Oh well, live and learn.
So, are my clutch plates doomed or can i revive them by switching out the oil?

Depends on how much damage was done and if the oil was the culprit. You should change the oil anyway, so give it a try.

ducpainter · April 12, 2009, 10:00:36 PM

Quote from: drenalinejunki92 on April 12, 2009, 09:52:41 PM
I think my problem is the oil, i recently did an oil change and was told car oil would be fine.(guess not) Oh well, live and learn.
So, are my clutch plates doomed or can i revive them by switching out the oil?

They lied.

I'd try an oil/filter change first.

If it hasn't been going on too long and you haven't glazed the plates it may come out of it.

Keep in mind that it may take a few miles after the change to get the car oil off the plates. You could speed it up by leaning the bike to the right slightly with the clutch lever pulled.

..and howie beat me to it.

Langanobob · April 13, 2009, 12:46:37 AM

Having an M620 myself I of course pay attention to M620 threads and there are a lot of them reporting M620 slipping clutches. I was pretty sure you had an M620 just from reading the post subject. I remember one thread, maybe on another board, where a guy was having trouble with his M620 clutch slipping using Mobil 1 Racing 4T 10W-40 synthetic motorcycle specific oil and his dealer told him the Mobil 1 was the problem and to switch to Castrol semi-synthetic blend. The discussion from the forum oil guru's was that the Mobil 1 was no way causing his clutch problem. But the guy posted back that after switching to Castrol synthetic blend his clutch problems went away.

My point is that although conventional wisdom seems to say that motorcycle specific full synthetic oil should be OK in a wet clutch, there is something different about the M620 clutches and they may work better with a motorcycle specific synthetic blend and when you change out the car oil the Castrol blend might be worth a try rather than a full synthetic. Don't think I'd go all the way back to a non-synthetic unless I was in a cool climate area, especially with no oil cooler.

Just passing these comments on for what they might be worth. I use Mobil 1 Racing 4T in my M620 without a problem so far, but I do a lot of highway riding and probably use the clutch less and also, being on the back side of 30 I'm not the adrenalin junkie that I used to be and don't ride as fast and hard either.

ducpainter · April 13, 2009, 05:19:06 AM

Quote from: Langanobob on April 13, 2009, 12:46:37 AM
Having an M620 myself I of course pay attention to M620 threads and there are a lot of them reporting M620 slipping clutches. I was pretty sure you had an M620 just from reading the post subject. I remember one thread, maybe on another board, where a guy was having trouble with his M620 clutch slipping using Mobil 1 Racing 4T 10W-40 synthetic motorcycle specific oil and his dealer told him the Mobil 1 was the problem and to switch to Castrol semi-synthetic blend. The discussion from the forum oil guru's was that the Mobil 1 was no way causing his clutch problem. But the guy posted back that after switching to Castrol synthetic blend his clutch problems went away.

My point is that although conventional wisdom seems to say that motorcycle specific full synthetic oil should be OK in a wet clutch, there is something different about the M620 clutches and they may work better with a motorcycle specific synthetic blend and when you change out the car oil the Castrol blend might be worth a try rather than a full synthetic. Don't think I'd go all the way back to a non-synthetic unless I was in a cool climate area, especially with no oil cooler.

Just passing these comments on for what they might be worth. I use Mobil 1 Racing 4T in my M620 without a problem so far, but I do a lot of highway riding and probably use the clutch less and also, being on the back side of 30 I'm not the adrenalin junkie that I used to be and don't ride as fast and hard either.

My only point was that 'energy conserving' oil was a bad thing for certain with regards to a wet clutch.

He should probably go back to whatever was in there prior to the slipping.

Langanobob · April 13, 2009, 07:26:58 AM

QuoteMy only point was that 'energy conserving' oil was a bad thing for certain with regards to a wet clutch.

He should probably go back to whatever was in there prior to the slipping.

Didn't mean to sound like I was counterindictionating anything you said, just adding some more thoughts on the subject. Also, I got the impression that he hasn't had the bike long and doesn't know what oil the PO had in it so he would have a hard time going back to whatever it was

.

Norm · April 13, 2009, 07:54:13 AM

Just for another oil opinion: I've always used car oil (both dino and synthetic) without problems on any brand of bike. However, I've always avoided the "star" oils. I've switched and have been using tractor dino oil for about a year now.

Langanobob · April 13, 2009, 10:14:54 AM

QuoteI've switched and have been using tractor dino oil for about a year now.

+1. I've used Shell Rotella T synthetic and it works fine.

ducpainter · April 13, 2009, 05:01:50 PM

Quote from: Norm on April 13, 2009, 07:54:13 AM
Just for another oil opinion: I've always used car oil (both dino and synthetic) without problems on any brand of bike. However, I've always avoided the "star" oils. I've switched and have been using tractor dino oil for about a year now.

Are the "star" oils the ones that are also called energy conserving?

My understanding is the friction modifiers are what affect the clutch.

If it wasn't the same source as the engine I'd say use TDH.

Howie · April 13, 2009, 10:44:46 PM

Quote from: ducpainter on April 13, 2009, 05:01:50 PM
Are the "star" oils the ones that are also called energy conserving?

My understanding is the friction modifiers are what affect the clutch.

If it wasn't the same source as the engine I'd say use TDH.

Energy conserving oils will have either "Energy Conserving I or II in the API doughnut symbol. All the starburst means it is API certified. The oil would have to be 10W-30 or thinner to be energy conserving. Certainly any energy conserving oil is not acceptable for a wet clutch and is too thin for our Ducs except for maybe some of our friends in the Arctic Circle. Car oil was not a problem for dry clutch bikes, but could now be a problem since oils rated higher than SJ have greatly reduced zinc and phosphorus content, needed to protect cams, rockers and transmission gears. Some oils may have other additives to protect those parts, some may not. This is one reason why many foreign brand cars are demanding oil that meet their specs. In short, use higher than SJ oilsin your bike at your own risk.

Back to wet clutches. There are two JASO specs for motorcycle oils. JASO MA is for wet clutches. JASO MB has friction modifiers. So do API SL oils, energy conserving or not. These oils can cause wet clutches to slip. Pre APC 620 clutches are more prone to slipping than the 750s since the springs are weaker APC clutches? Dunno.

Norm · April 14, 2009, 07:16:30 AM

Weren't the "good ol'" oils SG?

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Slipping/worn clutch help