Slipping Clutch on King Quad 300

[Valkman]

Hey all, new to the forum.  I just bought a 2001 King Quad, and the clutch is slipping. I adjusted the play with no improvement, so before I go through the trouble of replacing the clutch disc, I want to see if motor oil in it is the problem.  My question is Rotella T4 ok to use? I run in my motorcycles with no issues but I thought I'd get your input.

[basmn]

Check your oil. If you have a wet clutch  you require Jaso approval on the oil

[Mech]

I'd doubt the oil is the problem. The clutches aren't too fussy about the oil as long as it's an engine oil of the correct viscosity.

Unfortunately it's really hard to differentiate between the centrifugal clutch and the multiplate clutch when you are trying to diagnose them. You can use the shift lever to slip the plate clutch momentarily as you are accelerating at a rev above centrifugal clutch lockup speed and sometimes they will start slipping bad then, which suggests it is the plate clutch, but it's far from conclusive.

If the problem only happens at take off, and then seems fine once the revs are up, it tends to suggest it's the centrifugal, but again it's  not conclusive.

Luckily the two clutches are both together in the one side case, which can be got off in place, and are components we can inspect and measure once they are apart. That is really the only way to be sure you are fixing the right clutch.

[JustRandy]

2 hours ago, Mech said:

The clutches aren't too fussy about the oil as long as it's an engine oil of the correct viscosity.

That isn't true at all.  The additive package is the reason they make special oil for atvs and motorcycles.  And I've noticed from my own experience that using regular automotive engine oil immediately resulted in a clutch that didn't grab as well.  Auto oil is too slippery for wet clutches.

On 1/28/2023 at 4:49 PM, Valkman said:

My question is Rotella T4 ok to use? I run in my motorcycles with no issues but I thought I'd get your input.

I can't comment on that specific oil but it seems to me unless you're romping on your motorcycles (street bikes?) maybe the atv requires more friction which could give you a false sense of security regarding the oil you're using in your motorcycles.  The differences in friction requirements between machines is something to to think about.

But once the wrong oil is used there is no going back, so even if the oil is the cause of the slipping you'd still have to replace (or clean very well) the clutch disks.  You could try to wash the inside of the engine with kerosene then refill with proper oil, but who knows if that would work.

Every wet clutch is engineered to work in tandem with a lubricant with specific coefficients of friction.  That's why every automatic transmission requires a certain oil.

Another cause of clutch slipping is low oil, so I'd first check the oil level before proceeding.

The way to differentiate the clutch pack from the centrifugal clutch is to ride at a constant speed then suddenly gun it.  If it starts slipping then it's the clutch pack.  Another way is to gun it right after shifting into a higher gear and before letting off the shifter.

[basmn]

Reg engine oil contain friction modifiers.

JASO oils DO NOT.

Wet clutch packs do not like friction modifiers.

[JustRandy]

 

Looks like you are correct.  Although some JASO oils do contain the modifiers.

Quote

Japanese Engine Oil Standards Implementation Panel (JASO)

Modern passenger car engine oils contain more and more friction modifiers. While this is the good thing for those segments (reduces wear and fuel consumption) it's bad for the motorcycles. At least for those motorcycles which use engine oil to lubricate their transmission and wet clutch. JASO introduced the MA and MB specification to distinguish between friction modified and non friction modified engine oils. Most four-stroke motorcycles with wet clutches need a JASO MA oil.

JASO MA

Japanese standard for special oil which can be used in 4-stroke motorcycle engine with one oil system for engine, gearbox and wet clutch system. Fluid is non-friction modified.

JASO MB

MB grade oils are classified as the lowest friction oils among motorcycle four-cycle oils. Not to be used where a JASO MA grade oil is required.

 

https://www.oilspecifications.org/jaso.php

So you want JASO MA oil.

 

[Gwbarm]

Is rather confusing because the Rotella is T4 and the Suzuki oil is 4T 

[Mech]

There's different grades and brands of 4T..

The book says...

"Use only a high quality detergent IOW/40 motor
oi l with an API classification of SF or SG.".

 

 

[JustRandy]

I use this

Can't find it anymore though.  I bought cases of it in 2017 from amazon so I'm stocked for a while.  Walmart used to have it for $2/qt, but that's ancient history now.

[Jim Denton]

Shells advertising suggests to me that oil has a high blend of friction modifiers. I'd break it down and clean the dickens out of the clutch pack myself. I'd wash em in acetone to get rid of as much of that oil as I could and then do as this video suggests. 

 

 

[basmn]

I use rotella T6 full Synthetic in most all my toys and cars....NEVER had an issue...and it's JASO  rated...

[Jim Denton]

[JustRandy]

30 minutes ago, Jim Denton said:

Shells advertising suggests to me that oil has a high blend of friction modifiers. I'd break it down and clean the dickens out of the clutch pack myself. I'd wash em in acetone to get rid of as much of that oil as I could and then do as this video suggests. 

Good video.  Thanks for posting.

The guy said he tried brake cleaner but every brand of brake cleaner has different solvents or different ratios of fillers, propellants, and solvents.  Toluene is what you want and Walmart's super tech brand has the most of that according to the MSDS and from what I can tell by using it.  Hate to let the secret out of the bag especially since that brake cleaner had been fairly hard to find during the pandemic, but if any chemical is going to work it would be that.

But if I went to the trouble to tear it down I'd probably just buy new disks.  Actually, I have a set that's been soaking in oil for the last 4 years.  It turned out that the slippage was from being low on oil so I didn't need to change them yet.

[JustRandy]

37 minutes ago, basmn said:

I use rotella T6 full Synthetic in most all my toys and cars....NEVER had an issue...and it's JASO  rated...

Looks like that might be ok.  I'm not sure what all those specifications mean though.  But it does say JASO MA/MA2

[Jim Denton]

I learned the hard way about wet clutch certified oils. One fresh oil change and Shazam no clutch hookup. At the time I washed em and the used 120 grit sandpaper. Juat a light bit. 

[JustRandy]

1 minute ago, Jim Denton said:

I learned the hard way about wet clutch certified oils. One fresh oil change and Shazam no clutch hookup. At the time I washed em and the used 120 grit sandpaper. Juat a light bit. 

What oil do you use for wet clutches?

[Mech]

Gee you guys. We've had wet clutches for more than a hundred years, and the manufacturers know quite a bit about their design and operation...  What do you think we were doing for oils before the jaso standards were set ? We were doing what suzuki and every other bike manufacturer was telling us..  Using a suitable oil. They recommend a suitable oil, but it was never any jaso standard.

Now that we have modern cars and modern oils to choose from and a lot more additives than we used to, then sure we need to be careful what we do put in our bikes, but it doesn't mean that only the jaso certified oils are safe.

Just because some of you put some sort of car or truck engine oil in your bike and then had a slipping clutch, it doesn't mean we are all going to put the wrong oil in... If we follow the manufacturers recommendations and read the oil's label we will be right.. Old suzuki's do not have to have jaso certified oils in them.. There was no jaso oil spec when they came out...  They ran fine for years with common old mineral oils.

Please stop insisting that we have to use jaso certified oils..  It's not true. There are heaps of oils out there that are of better quality and imminently suitable, and cheaper, than some of the bike shop oils that have a jaso rating.

[Mech]

Anyway Valkman, unless the oil you have is totally unsuitable for a wet clutch, which seems unlikely given you use it in your bikes, I think you are going to have to take the side cover off and inspect and measure both clutches. I'd recheck the clutch adjustment first though and perhaps try adjusting it with a bit more play than suggested just to make sure there isn't a bit too much stiffness in the cable or gear change linkages or anything.

[Valkman]

Thanks for all the replies everyone.  I'm thinking either way I'm going to have the pull the cover off and replace something. Let me tell you what my atv is doing , because I'm not that familiar with centrifugal clutches.  It shifts fine and accelerates fine but when I upshift it starts to slip when it gets loaded. If downshift (removing the load) the clutch will fully engage again. Any ideas as what actually happening. 

[Mech]

Ok, if it's made worse by shifting up but not down then it sort of points to the plate clutch. The shift lever has some linkages that operate the plate clutch. The clutch gets operated before the gears begin to shift, so the first bit of lever movement up or down is only operating the clutch.. If an up shift causes the clutch to slip, but after a downshift the clutch feels fine again, even if you are accelerating in that lower gear after a shift, then I'd say your lever, or the linkages, aren't coming right back to center after an up shift, so the clutch is being held slightly on(slipping). I'd disconnect the shift cable at the box and check it's free and then I'd feel by hand whether the shift lever on the side of the box seems to self center fully after an up shift...

Then, if you are sure the upshift is making it bad, and the downshift fixes it(test it by doing a downshift from fifth to forth and then accelerating hard), I'd inspect the internal linkages operating the clutch.. as I was inspecting the plate clutch.

[Mech]

Actually, there's a better way to test your clutch..  The first bit of movement of the shift lever operates the clutch, and then the gears move. If you change down a gear and keep your toe on the lever you will be holding the clutch in, and if you then let the bike roll down to a lower speed and then rev the engine before letting your toe up, that plate clutch is going to get dropped  with the engine revving and it should try to rocket you forwards. If the slippage is caused by a worn out clutch then dumping the clutch like that is going to make it slip badly. If the clutch is good still, and it's only the non-self centering that's the problem , then dumping the clutch like that after a down shift will hopefully make the clutch grab and rocket you forwards as it should. 

 

You could try the same technique on a down and an up shift and compare the results to try and decide whether it's a worn clutch, bad linkages, or a bit of both.

[Mech]

Also... the standard test as set out in the manual, testing first engagement revs, and then  full lock-up under load revs, should give a good indication of centrifugal clutch wear..  and allow us to deduce if the plates are the culprit.. sometimes.. maybe..  haha

If the first engagement revs are right, then the centrifugal clutch shoes are not very worn, and so if we get slippage at and beyond full lockup revs, then we are likely seeing plate slippage. If it's late to start moving at the start of engagement revs though, then we can assume the centrifugal shoes are worn, and if we then get slippage at full lockup and beyond revs it might well be the centrifugal clutch.. but it might be both clutches worn..  The only way to be sure we are replacing the correct clutch is by stripping them and measuring and inspecting.. 

[JustRandy]

3 hours ago, Mech said:

We've had wet clutches for more than a hundred years, and the manufacturers know quite a bit about their design and operation...  What do you think we were doing for oils before the jaso standards were set ?

JASO MA is basically oil without the friction modifiers invented recently.  So it's basically the old oil you're referencing.  JASO MA is a way of avoiding the new stuff.

Same goes for the SF that I use.  Says on the bottle "1988 and earlier".

 

3 hours ago, Valkman said:

It shifts fine and accelerates fine but when I upshift it starts to slip when it gets loaded. If downshift (removing the load) the clutch will fully engage again. Any ideas as what actually happening. 

That means it's your clutch pack and not the centrifugal clutch.

That means either your engine is low on oil, or your clutch isn't adjusted right, or your oil is too slippery, or your clutch disks are too worn.

Check the oil level.  I know it's not easy with that sight glass.  Sometimes it helps to jack up one side of the atv until you can see a line of oil.  Be sure the oil level is right before going to the trouble of tearing the engine apart.

If the oil level is ok and you're sure the clutch is adjusted right then you may as well order some clutch disks and springs.  Soak the fiber disks in the correct oil at least overnight.

I'd go to thumpertalk and ask which oil they use.  There are more people there.  The oil I use isn't available anymore and Mech doesn't know what he's talking about.  I'd want at least 2 guys to agree on the same recommendation and there's not enough people here for that.

Or you could just buy the expensive stuff that says ATV on the bottle.  For example https://www.walmart.com/ip/Valvoline-4-Stroke-ATV-UTV-SAE-10W-40-Motor-Oil-1-QT/19514362

Don't forget to get a new oil filter.

I refill the oil through the intake valve inspection cap.  It's way easier.  There's a hole in the frame that will fit a long skinny funnel.

[basmn]

5 hours ago, Mech said:

Gee you guys. We've had wet clutches for more than a hundred years, and the manufacturers know quite a bit about their design and operation...  What do you think we were doing for oils before the jaso standards were set ? We were doing what suzuki and every other bike manufacturer was telling us..  Using a suitable oil. They recommend a suitable oil, but it was never any jaso standard.

Now that we have modern cars and modern oils to choose from and a lot more additives than we used to, then sure we need to be careful what we do put in our bikes, but it doesn't mean that only the jaso certified oils are safe.

Just because some of you put some sort of car or truck engine oil in your bike and then had a slipping clutch, it doesn't mean we are all going to put the wrong oil in... If we follow the manufacturers recommendations and read the oil's label we will be right.. Old suzuki's do not have to have jaso certified oils in them.. There was no jaso oil spec when they came out...  They ran fine for years with common old mineral oils.

Please stop insisting that we have to use jaso certified oils..  It's not true. There are heaps of oils out there that are of better quality and imminently suitable, and cheaper, than some of the bike shop oils that have a jaso rating.

Mech, back in the good ole days we didn't have to worry about friction additives in oils because they hadn't been invented yet. Oil was oil...a wet clutch was a wet clutch...technology changed all that. You can put what ever you like in your crankcase,  your call.

[Jim Denton]

Man oh man, mention oil preferences on any forum and you're guaranteed to start a war. Too funny. Mech, great diagnostic writeup, thanks.