• 4 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    TE = 4st Enduro & TC = 4st Cross

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Sudden clutch slipping

Tom H

Husqvarna
B Class
Guys,

I've got a 2011 SMR511 with under 5000kms on the clock. Today I went riding and was getting some pretty massive clutch slip in all gears under hard acceleration.

This is the first time I've felt it on this bike. I rode it to work all week and had no issues. Last week I was practicing clutch wheelies but didn't see any slip at all. And then of course I rode it to work all week and didnt see it.

Any ideas? I don't think the clutch can be worn this early into its life? And I don't think I've worn the plates out doing wheelies because I rode it alot since.

I did see some oil under the bike at work the other day but I assumed it was from hard riding again? Low oil levels can't do it, can they? Do I need to bleed the hydraulic system? Neither of those seem to make sense! I'm sure this is a quick fix!
 
Fooling around practicing wheelies can burn some clutch plate, low oil level can't help...
Drag racing my street bikes, I have toasted a clutch or two, sometimes while I was abusing it,
Sometimes later, just riding around....at 5000 mi., the way we drive these bikes, if your
Having slippage, remove the cover, check/replace plates, check, measure springs/replace...
Bleed, check for,leaks, and be good for awhile....
 
There are two clutches in the Kymco engine. Your manual clutch and your torque limiter. Just curious, what brand of oil do you use, which weight and how much do you add?
 
Yeah, I understand it could be the plates. But I just wonder why it wasnt slipping until a week later?
 
There are two clutches in the Kymco engine. Your manual clutch and your torque limiter. Just curious, what brand of oil do you use and which weight?

I've just been using 10W40 Mobil. Could it be the torque limiter then? What could be wrong with it? I'm going to replace the oil and bleed the hydraulics this morning and see if that makes a difference. Do you think that would help? I'm going away for six weeks and goddamnit, I want to enjoy my bike today before I leave tomorrow!
 
It's easier to test the clutch first. It seems early for the clutch though. Many of us run Mobil 0w40 which is a little better for the clutch. As far as the TL goes, there is no set time on that, Ty has blown them up in one race before. Best way to guard against TL destruction is the breather mod, etc.(sorry for the infomercial there). After you drain your oil, the clutch is easy to get to by just removing the round clutch cover.
 
Yeah, fair enough. But then of course Id need replacement plates which isn't likely to happen today or get me on the road today. Sigh.
I'll throw some 0W40 in and bleed it and see if it stops slipping. Do you think that's likely to work?
Is the breather mod the TC airbox?
 
No, what happens is that hot gasses flow from the back of your piston through the TL before exiting. This anneals and weakens the pressure plates in the TL causing it to loose pressure and slip. By venting these gasses out the valve cover, they bypass the TL and it remains cool in a larger bath of oil. But, it may be your manual clutch and you wouldn't know for sure until a tear down can be preformed.
 
Do you know what would cause the clutch slipping to have started so suddenly? It just doesnt seem to make sense that the wheelies could have done it. It was fine on Thurs and shit on Sat. It just doesnt make sense to me!
 
It could start suddenly if the basket on the clutch is grooved/notched enough to hold the clutch plates from engaging
Completely. I have no experience with the torque converter, other than looking at the diagram.
Tinken is probably right in his thoughts, hope you have luck, let us know. If it's not the converter, remember to check
For a failed spring, more than once I have seen, this cause cocking of the plates, which in turn decreases the area of
Engagement...
 
No, what happens is that hot gasses flow from the back of your piston through the TL before exiting. This anneals and weakens the pressure plates in the TL causing it to loose pressure and slip. By venting these gasses out the valve cover, they bypass the TL and it remains cool in a larger bath of oil. But, it may be your manual clutch and you wouldn't know for sure until a tear down can be preformed.

I hope this isn't off topic, but I'm interested in the details of the TL. I assume the pressure plates are aluminum if they are annealed by hot crank case gasses, because 600+ degrees would be required to anneal aluminum and steel plates 1500+degrees. A vent hose of a very high heat rating must be used? Just curious:thinking:
 
Do you know what would cause the clutch slipping to have started so suddenly? It just doesnt seem to make sense that the wheelies could have done it. It was fine on Thurs and shit on Sat. It just doesnt make sense to me!
If you are only running 800cc of oil like Husqvarna instructed everyone to do (50% less than originally recommended was colossally ignorant imo, just to solve the oil in filter issue), then when flat, your clutch was really only getting oil once your bike was hot and only when it was level. Any kind of hill climb or wheelie upward would slosh the oil backwards and into the dry sump starving the clutch and the TL for sure and possibly oil pumps too. There are no springs in the clutch, it uses a pressure plate on top (7707035). It may of worn over time or the clutch plate went. If it is your torque limiter, the whole thing is one part, around $220 last time I checked.
 
I hope this isn't off topic, but I'm interested in the details of the TL. I assume the pressure plates are aluminum if they are annealed by hot crank case gasses, because 600+ degrees would be required to anneal aluminum and steel plates 1500+degrees. A vent hose of a very high heat rating must be used? Just curious:thinking:

Not only 600 plus, but hours at sustained temps.
 
Well, I changed the oil and bleed the system. No change.
So Tinken, does that mean that if I'm doing wheelies frequently I need to add more than 800cc of oil? That might have been what did it, I guess.

Is there a way to put heavy duty clutch plates in thatd last longer?
 
I started a new thread on the torque limiters here:
http://www.cafehusky.com/threads/449-511-torque-limiter-failures.32792/

Well, I changed the oil and bleed the system. No change.
So Tinken, does that mean that if I'm doing wheelies frequently I need to add more than 800cc of oil? That might have been what did it, I guess.

Is there a way to put heavy duty clutch plates in thatd last longer?

What I suggest you do is add the breather vent to your valve cover and also a breather bottle. This will bypass the hot gas from the TL and push it out the top. We have found this eliminates more pressure too. Any oil that blows by is collected and cooled in the breather tank and then returned to the engine. This allows you to use a full quantity of 1150cc of oil which will aid in the cooling and proper function of your clutch as well as the torque limiter. Wheelie all you want, there will be sufficient oil to cover the Eaton pump #2 which sprays oil on the clutch, RH crank bearing and the torque limiter.
 
So the parts are running at 600+- degrees (the minimum temp required to anneal aluminum) for hours?

Some would have us believe so , I personally don't. (that's if the plates are Al, I don't know what they are, but if steel as I suspect, we talking much higher temps)
 
Some would have us believe so , I personally don't. (that's if the plates are Al, I don't know what they are, but if steel as I suspect, we talking much higher temps)
Well if they are steel, there is a major problem regarding temperature. Like 1000 degrees. Wouldn't you say?
Edit, I'm asking questions to try and learn something here. There is probably a reason clutches have always been run off the primary drive?
 
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