clutch slipping... coincidence?

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I'm wondering if it's oil related. 18000km on my vulcan 900, I ride two up, hit the throttle fairly hard every now and then and have some performance mods. Still, the dealer says that 18000 is premature.

The bike has had it's oil changed for the 5th time. First 2 changes were Motul Full Synthetic, this is what the selling dealer preferred. Oil change 3 was Kawasaki S4 Full Synthetic. Oil change 4 was Motul semi-syn. This was done in a pinch at another dealer's service dept, I was pressed for time, they weren't Kawasaki and they wanted waaaay too much for a Full Synthetic oil. Oil change #5 was last week, back to Kawasaki S4. And that is the day that the clutch started to slip, on the highway, while passing, under hard throttle.

It is at a Kawasaki dealer and I got the phone call today: "Hi, did you by any chance put car oil in the bike?"

- no, why?

"because the mechanic working on it wants to know, says the friction discs look weird and it looks like there's car oil in the bike."

- nope, Kawi S4, purchased at your parts department and changed by me, no car oil, no way.

"okay, I'll let him know".

Did I create a witch's brew on the clutch plates or is it one really big coincidence? That's part 1.

Part two is I got another phone call saying mechanic prefers to a)discard the fresh oil in the bike because he didn't like what the clutch looked like and b)refill with mineral oil to brake the clutch in. I said, sure, go ahead. Any validity to this and how long should I wait before running Kawi S4?
 
ummmmm.... motorcycle oil?

seriously, no idea on the motul synthetic. All I know is that the selling dealer... not the one that the bike is at, used bulk motul. I stopped going there because poorly written work order almost cost me an engine. Anyway... bulk motul synthetic motorcycle oil is the best I can do.

The semi-syn was motul 5100 4T
 
and HERE it is... someone else's bike didn't like 4T

""Verified Purchase
made my transmission shift easier. all the motorcycle shops in this area carry it. good selection of weights, unlike other synthetics

UPDATE: Do NOT use this in motorcycles with wet clutches. Clutch will slip, even long after it's been changed out. May require replacement of your clutch basket. Container should have a warning.""
 
Originally Posted By: otterhead
and HERE it is... someone else's bike didn't like 4T

""Verified Purchase
made my transmission shift easier. all the motorcycle shops in this area carry it. good selection of weights, unlike other synthetics

UPDATE: Do NOT use this in motorcycles with wet clutches. Clutch will slip, even long after it's been changed out. May require replacement of your clutch basket. Container should have a warning.""



A 4T oil is made for bikes,so I've gotta call bull on this one.
And motul is top shelf oil,one of the best money can buy,so it's not the oil,unless the factory has made an error in bottling.
I use rotella t in my Harley's primary,and even at close to double stock power levels I've got no slip whatsoever and I'm still on the stock clutch too.
Only once did I get clutch slip and that was after using Mobil 1 15w-50 in the primary. Almost immediately I felt it slip passing on the highway.
I'll never pay big bucks for a bike oil ever again. Rotella does just fine and since I just can't run past 3000 mile intervals on my bike anyways there's absolutely no point using a synthetic oil,not for me anyways.
And the only oils that ran quieter than rotella were motul and royal purple 20w-50 automotive oil,which cost almost as much as a 5 gallon pail of rotella for 2 oil changes,which is insanity in my eyes.
 
If your clutch has been heavily slipping for long it may be too late.

Usually mild slippage caused by an oil, you can revert to a known strong clutch oil and it will take care of the issue.

There really is no stronger clutch oil than Rotella, I don't care for the stuff, but if it slips on that your not going to fix it with oil.
 
Technically speaking there is no car oil that can not defeat a wet clutch
in good working order... what is confusing the issue is the fact that
all motorcycle wet clutches will reach a point in their life and start
to slip... no one complains about clutch slip when the bike is new...
but on about the 27K to 57K range is when containment may build up to
point where the clutch begins to loose its grip... this is usually
discovered by the owner during WFO (Wide Fooking Open)throttle like at
a track day... in error one can blame the oil but its really the
contaminants on the clutch plates...
 
Technically speaking
oem Clutch strength varies by model even brand new, some models are far more susceptible to oil slickness than others.

Example is when Honda came out a few years back, when people began having issues with Hondas moly oil, not to use it other than for specified models.

A motorcycle with sub 50,000 mile clutch life is probably better off with a stouter grip oil.
 
Last edited:
Originally Posted By: otterhead

UPDATE: Do NOT use this in motorcycles with wet clutches. Clutch will slip, even long after it's been changed out. May require replacement of your clutch basket. Container should have a warning.""


replacement of the clutch basket???????

HA HA HA HA HA

o m g!!! i guess someone does not actually know how the clutch in a motorcycle works.
 
I made the mistake once of putting castrol syntec into my ATV and it started to slip the centrifugal clutch under high loads in high gears. Changed it out to Rotella 15W40 and the slipping went away after a few hours. That was ~200 hours ago and the clutch still doesn't slip and functions like new.
 
clearly the castrol syntec exposed your worn clutch.

and now the SRT is doing everything it can to prevent that slippage.
put the calipers on those clutch plates, they wont be in spec.
 
Originally Posted By: sunruh
clearly the castrol syntec exposed your worn clutch.

and now the SRT is doing everything it can to prevent that slippage.
put the calipers on those clutch plates, they wont be in spec.

Hmmm, I don't know, it had probably done 400 hours when I put in the syntec, now it still clutches fine 200 hours later. If the clutch went out of spec in 400 hours, what are the odds it still gripping with 50% more hours? Seems unlikey to me.
I probably won't bother to check until it starts slipping with the rotella in it. I only use it at home and 1st gear in super low requires nearly no hp to move the atv to limp it back to the shed.
 
Solved! Not the oil. Picked it up today. When the bike was new, I found that the clutch was a bit "high", would start to grip with the lever 7/10's of the way out. Mentioned it to the selling dealer... they're all like that. 2 years later it was in for service, mentioned the high clutch again, this time at a non-kawi dealer... all ok.

Rode it today... clutch starts to grab at about 2/10ths. I guess it died a slow painful death.

Repairing dealer did refill with conventional 10w40 oil and said leave it in for 1000. I ride about 5k a year, mostly highway... is synthetic even worth it? rotella T?
 
Last edited:
Originally Posted By: otterhead
is synthetic even worth it?



100% synthetics maybe worth the extra cost if you value these advantages...

1 Little or no VI (viscosity improvers) to shear down between the gears...

2 Less internal friction and heat which equals more rear wheel HP...

3 Ability to lubricate quicker at start up...
 
Last edited:
Originally Posted By: IndyIan
I made the mistake once of putting castrol syntec into my ATV and it started to slip the centrifugal clutch under high loads in high gears. Changed it out to Rotella 15W40 and the slipping went away after a few hours. That was ~200 hours ago and the clutch still doesn't slip and functions like new.


You never mentioned what viscosity of Castrol Syntec was suspect???
 
Originally Posted By: BusyLittleShop
Originally Posted By: otterhead
is synthetic even worth it?



100% synthetics maybe worth the extra cost if you value these advantages...

1 Little or no VI (viscosity improvers) to shear down between the gears...

2 Less internal friction and heat which equals more rear wheel HP...

3 Ability to lubricate quicker at start up...



And every point you've made is only partly true,if at all.
In my experience with my shared sump bikes 10w-40 synthetic bike oil sheared faster than rotella, which became obvious by how the bikes shifted and how noisy the bikes became.
To imply that a synthetic reduces friction over a conventional is a total and absolute lie. To imply that heat is reduced is also absurd. Oils of the same grade shed heat in the same way,so to imply that shows your knowledge about oil in general.

To imply that there are less viscosity index improvers can be argued both ways. It's grade and basestock specific,as well as brand.

So basically your incorrect with every comment. Stick with turning a wrench because if you are actually telling your customers this stuff you should be ashamed of yourself,especially with all the info available in this forum that you obviously choose to ignore because it doesn't fit your model of synthetics.

Synthetic oils don't reduce friction any more than conventionals do. The reduction of friction is based in the friction modifiers contained in an oils additive package.
Synthetic oils do have advantages though,only you haven't mentioned any of them.

They are more oxidatively stable,able to withstand more heat before breaking down,which translates into longer drain intervals.
They tend to produce less deposits as they break down,however they are less able to remove deposits as well,as indicated by industry professionals in white papers posted on this site.

So OP yes synthetics do have advantages however think about whether you require these advantages and whether they are worth the extra money.
Conventional rotella works great for me and I'll tell you why.
I'm not interested in extended drains in my bike. 3000 miles is the max I'm going,which is an utter waste for a synthetic.
I'm not spinning the engine at 12000 rpm. My Harley maxes out at 6200,the shadow at 8000,iirc,my venture is a cruiser so 7000 at the very most.
Your bike is liquid cooled,so oil temp is going to be better controlled and will tend to be lower than an air cooled engine at low speeds.

Now if I was riding a high rpm street screamer then maybe a high priced syn will make sense however I'm not. And unless your going to take advantage of the extended drain ability why bother.
A shared sump bike accumulates all the combustion bi-products,and the clutch disk impurities so in my shared sump bikes I change the oil as soon as shifting gets notchy,at around 2500-3000 miles with rotella.
When I used Mobil 1 10w-40 4t motorcycle oil shifting was notchy before 2000 miles,amsoil was a bit better at 2200 miles,but neither resisted shear better than conventional rotella in my shared sump bikes.

Busy little shop. I suggest using this sites vast information to your advantage and absorb it,because I recall you saying these same things last year,and you were wrong then,just as you are now.
You are spitting out the old wives tales that were disproved years ago,however you either didn't get the memo or are choosing to ignore it. Either way if your going to "help" with information try truth and stop pushing wives takes we all here know to be false.
 
When talking synthetics we have to remember that in the USA Group III basestocks are considered synthetics and are often sold as so, where as in other nations only Group IV and Group V can be called synthetics.

Group III "synthetics" do tend to shear down faster than a group IV/V.
 
Originally Posted By: Clevy
Originally Posted By: BusyLittleShop
Originally Posted By: otterhead
is synthetic even worth it?



100% synthetics maybe worth the extra cost if you value these advantages...

1 Little or no VI (viscosity improvers) to shear down between the gears...

2 Less internal friction and heat which equals more rear wheel HP...

3 Ability to lubricate quicker at start up...



And every point you've made is only partly true,if at all.
In my experience with my shared sump bikes 10w-40 synthetic bike oil sheared faster than rotella, which became obvious by how the bikes shifted and how noisy the bikes became.
To imply that a synthetic reduces friction over a conventional is a total and absolute lie. To imply that heat is reduced is also absurd. Oils of the same grade shed heat in the same way,so to imply that shows your knowledge about oil in general.

To imply that there are less viscosity index improvers can be argued both ways. It's grade and basestock specific,as well as brand.

So basically your incorrect with every comment. Stick with turning a wrench because if you are actually telling your customers this stuff you should be ashamed of yourself,especially with all the info available in this forum that you obviously choose to ignore because it doesn't fit your model of synthetics.

Synthetic oils don't reduce friction any more than conventionals do. The reduction of friction is based in the friction modifiers contained in an oils additive package.
Synthetic oils do have advantages though,only you haven't mentioned any of them.

They are more oxidatively stable,able to withstand more heat before breaking down,which translates into longer drain intervals.
They tend to produce less deposits as they break down,however they are less able to remove deposits as well,as indicated by industry professionals in white papers posted on this site.

So OP yes synthetics do have advantages however think about whether you require these advantages and whether they are worth the extra money.
Conventional rotella works great for me and I'll tell you why.
I'm not interested in extended drains in my bike. 3000 miles is the max I'm going,which is an utter waste for a synthetic.
I'm not spinning the engine at 12000 rpm. My Harley maxes out at 6200,the shadow at 8000,iirc,my venture is a cruiser so 7000 at the very most.
Your bike is liquid cooled,so oil temp is going to be better controlled and will tend to be lower than an air cooled engine at low speeds.

Now if I was riding a high rpm street screamer then maybe a high priced syn will make sense however I'm not. And unless your going to take advantage of the extended drain ability why bother.
A shared sump bike accumulates all the combustion bi-products,and the clutch disk impurities so in my shared sump bikes I change the oil as soon as shifting gets notchy,at around 2500-3000 miles with rotella.
When I used Mobil 1 10w-40 4t motorcycle oil shifting was notchy before 2000 miles,amsoil was a bit better at 2200 miles,but neither resisted shear better than conventional rotella in my shared sump bikes.

Busy little shop. I suggest using this sites vast information to your advantage and absorb it,because I recall you saying these same things last year,and you were wrong then,just as you are now.
You are spitting out the old wives tales that were disproved years ago,however you either didn't get the memo or are choosing to ignore it. Either way if your going to "help" with information try truth and stop pushing wives takes we all here know to be false.


Well, that answers my questions. Thanks.

What I do know is that on previous bikes, I would have to top off conventional oil after a few day long highway rides. Never had to top off synthetic. To me, synthetic resists heat better than conventional oil... but what nags me is the guy that rebuilt my clutch doesn't like full syn, he runs semi-syn in his bike... which I find weird and makes me question his preference.
 
Last edited:
Originally Posted By: BusyLittleShop
Originally Posted By: IndyIan
I made the mistake once of putting castrol syntec into my ATV and it started to slip the centrifugal clutch under high loads in high gears. Changed it out to Rotella 15W40 and the slipping went away after a few hours. That was ~200 hours ago and the clutch still doesn't slip and functions like new.


You never mentioned what viscosity of Castrol Syntec was suspect???

It was 5W50 but back then it had the VW 502 or 505 spec, which I seem to recall reading somewhere isn't a good spec for a wet clutch.
My atv is a 01 suzuki kingquad 300, so it might have 20hp, but then it also spends alot of time moving 2000lbs of quad, rider, and trailer up my hills.
 
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