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Slip Slip Slip

6K views 96 replies 13 participants last post by  Gas Man 
#1 ·
Ok, so I've noticed a small problem..... and want to bounce some ideas around.

Ever sense I went back to stock gearing on my 9R I have noticed a problem. In 4th gear and only in 4th gear at about 6K RPM if I WOT the bike the clutch will start to slip. Not in 1,2,3,5,6, just in 4th. Everything else it's just all power.

I changed the oil and filter just as a caution. I run Amsoil Full syn 10W-40. I spoke to the head guy at a Kawasaki dealer and he said they just spoke about this with the 10R at a Kawasaki cert. class. He said it is a matter of gearing vs power.

Allow me to TRY to explain like he did. For my bike and it's gearing right now, 4th gear at that RPM and at that speed. When I go WOT the motor wants to go and go now. But with the taller gear on the rear wheel and tranny it wants to slip slightly. Add in super slippery synthetic oil and you got slipage. It doesn't do it in 3rd because the gear is shorter and doesn't do it in 5th because it's so tall or I'm going so fast by then that there just isn't enough engine power to spin it.

We both figure that when I change the gearing the problem will probably want to migrate to a higher gear...maybe 5th. But that if it gets too high it may disappear completely due to dealing with higher and higher gearing.

This is all a mizture of 14K on the bike and synthetic oil. At least that is what we figured. But I'd like to hear some of your thought on it. Some of you have dealt plenty on slipping clutchs and stuff like that... so :help: a guy out.

He also suggested a "clutch test"... put the front wheel to a brick wall and in 2nd gear start to let the clutch out..slowly...don't pop it cause it will just want to spin the back tire...but slowly and if it don't start to free spin the motor, the clutch is fine.... any thoughts on that?
 
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#2 ·
Sounds like you hit the point of diminishing returns in 4th gear...from the physics view, it makes sense, and if you "shortened" the gear in fourth, it could send it to 5th, or you could reach the same point in fourth where the engine doesn't overpower the gearing...question is...are you ready to tear the tranny apart and have multiple 4th gears machined to different specs. to find one to solve the problem completely?
 
#4 ·
bumblebee said:
Sounds like you hit the point of diminishing returns in 4th gear...from the physics view, it makes sense, and if you "shortened" the gear in fourth, it could send it to 5th, or you could reach the same point in fourth where the engine doesn't overpower the gearing...question is...are you ready to tear the tranny apart and have multiple 4th gears machined to different specs. to find one to solve the problem completely?
:iagree: your 4th gear may be worn.
 
#6 · (Edited)
Everything in the first post is correct.
A slipping clutch is just what it is "slipping" The resolve is simple. You either need new clutches or heavier springs. Worst case you need a clutch basket due to it wearing out but lets not jump to that yet. A gear its self can not slip I dont think. It is splined to the shaft it rides on. And you can certainly tell the difference between missing teeth and slippage. Other simple might be repairs is, Go to semi synth or regular dino oil. This will improve the clutch bite over a full synth oil. And remember Your oil must be up to operating temp to perform on the clutches So dont feel like evything is at a loss if the slippeage only seems to occure when you first get going out for the day. At temp you will encounter less slipage. If it has been slipping a lot imo it is only going to get worse as the clutch plates and steals are getting a chance to wear thin from the slipping. So in a nut shell, If your know oil is good and fresh rule it out.
If you know Clutches are relatively new and the cable is adjusted correctly with free play, rule this out also.
if your clutch is bone stock and your riding style isnt then you might be ready for a more agressive set-up. Tighter springs and better clutches and metel plates.
Only you can answere these Or take it to a shop. But if the rider dont ride at your level of agression he may not feel it. :2cents:
I sure Hope something in my post makes sence. All in all Good luck.
 
#8 ·
FWIW, here's my take on it...I am sure you could get the clutch to slip in the higher gears as well, but you might have to load it differently. For example, take it to 8k rpm in 5th or 6th (note: very illegal speeds required here), back off the throttle momentarily, then snap it WFO...my guess is it will slip.

The fact that you are experiencing slip under limited conditions shows that your clutch is just beginning to fail. Now is the time to make the repairs before more damage is done. Just remember that your engine uses the same oil as the clutch...as the clutch begins to deteriorate, where do you think all those little particles go? Hopefully, most of them will be trapped in the oil filter...hopefully.

The only thing that "clutch test" will guarantee is that if your clutch isn't fried now, it will be. In fact, I wouldn't want someone to treat my bike that way...seems like back-woods diagnostics to me. You already know the clutch is slipping, pull it apart and figure out why the right way...there are measurable service limit specifications for all of the wearable parts in a clutch.

Finally, I highly recommend you use OEM friction plates along with either OEM steel or aftermarket cryo-treated aluminum plates. About the only other aftermarket clutch parts I recommend is heavy duty clutch springs, but you shouldn't need those unless you power output is up significantly from stock.

Larry
 
#9 ·
larryg said:
FWIW, here's my take on it...I am sure you could get the clutch to slip in the higher gears as well, but you might have to load it differently. For example, take it to 8k rpm in 5th or 6th (note: very illegal speeds required here), back off the throttle momentarily, then snap it WFO...my guess is it will slip.

The fact that you are experiencing slip under limited conditions shows that your clutch is just beginning to fail. Now is the time to make the repairs before more damage is done. Just remember that your engine uses the same oil as the clutch...as the clutch begins to deteriorate, where do you think all those little particles go? Hopefully, most of them will be trapped in the oil filter...hopefully.

The only thing that "clutch test" will guarantee is that if your clutch isn't fried now, it will be. In fact, I wouldn't want someone to treat my bike that way...seems like back-woods diagnostics to me. You already know the clutch is slipping, pull it apart and figure out why the right way...there are measurable service limit specifications for all of the wearable parts in a clutch.

Finally, I highly recommend you use OEM friction plates along with either OEM steel or aftermarket cryo-treated aluminum plates. About the only other aftermarket clutch parts I recommend is heavy duty clutch springs, but you shouldn't need those unless you power output is up significantly from stock.

Larry
:iagree: a question for ya larry since youve worked on many different makes of bikes, ive always had the best luck with suzuki oem clutches but thats because ive really only dragraced suzukis from stock to 200 rwhp nos gsxr's and have found that suzuki oem friction plates are better than anything else out there, but how is yamaha, kawasaki and honda oem clutches, are they as good as suzuki's oems? are all oem clutches sort of all the same, ....I think that made sense??????
 
#10 ·
Well, everybody tells me that there is nothing in the tranny that would cause it to slip only when under load. So that rules that out... no biggie either way on that cause the bike is still under warrenty.

I'm going to go with weakend clutch springs..... which was also spoke of at the dealer. In any affect, the clutch isn't covered under warrenty.

If I decide to replace the clutch I will just go with stock clutch unless somebody can show me some real good facts to do otherwise. Also, even though I do have more power output then stock nothing that should say I should look for anything stupid stronger.

There is no free play in the clutch lever and I just replaced the oil to rule that out, as I said in my first post.

Last year the clutch was out of the bike for a water pump repair (by the dealer) and the mechanic said that the clutch was in great condition for then 12k miles... however, I don't think that would say much about the spring stiffness...

I rode the piss out of the bike today and expierence no problems with it. Of coarse I avoid that problem area...

Larry... I am going to pm you a few questions...

Does my line of thinking seem about right?
 
#11 ·
There is no free play in the clutch lever
There HAS to be free play in the lever or you could be pre-engauging the clutch a bit. It would be like your allready pulling it. You need to have like an 1/8th of inch of "clutch lever free play or slop" if you will to ensure the clutch basket is fully closed. If your lever it tight against the lever mount it could be slightly engaged. End result "slippage".
And just as stated those particals are in there so an oil change is necessary. :2cents:

Good Luck,
 
#12 ·
Earlzach said:
There HAS to be free play in the lever or you could be pre-engauging the clutch a bit. It would be like your allready pulling it. You need to have like an 1/8th of inch of "clutch lever free play or slop" if you will to ensure the clutch basket is fully closed. If your lever it tight against the lever mount it could be slightly engaged. End result "slippage".
And just as stated those particals are in there so an oil change is necessary. :2cents:

Good Luck,
Ya the " no free play" got me thinking also, I always like to have the clutch engage right off the handle bar..this way i was sure it was fully engaged when released, if you have no play in your clutch lever then i bet your not engaging till your way off the bar and that alone could result in slipping since it might not be fully engaged or just a little pressure might disengage it...

as far as clutch particles, thats why i use to change the oil after every dragstrip day since slipping the hell out of the clutch at high rpms would get particles in the oil and just in case some get by the filter or just sit in the sump....
 
#13 ·
GsxrJack said:
Ya the " no free play" got me thinking also, I always like to have the clutch engage right off the handle bar..this way i was sure it was fully engaged when released, if you have no play in your clutch lever then i bet your not engaging till your way off the bar and that alone could result in slipping since it might not be fully engaged or just a little pressure might disengage it...

as far as clutch particles, thats why i use to change the oil after every dragstrip day since slipping the hell out of the clutch at high rpms would get particles in the oil and just in case some get by the filter or just sit in the sump....
You should be able to turn your finger sideways and put it between the clutch lever and the mount, thats what I was told anyway to get the proper clutch play. So about 1/8 to 1/4 inch of play. Plus with that many miles I would replace it anyway. I wouldn't think that the springs are bad but if you replace the clutch do them anyway.

Getting an after market clutch is the best bet, the kevlar clutchs are awsome and will last along time along with some quality springs.
 
#14 ·
twisty said:
You should be able to turn your finger sideways and put it between the clutch lever and the mount, thats what I was told anyway to get the proper clutch play. So about 1/8 to 1/4 inch of play. Plus with that many miles I would replace it anyway. I wouldn't think that the springs are bad but if you replace the clutch do them anyway.

Getting an after market clutch is the best bet, the kevlar clutchs are awsome and will last along time along with some quality springs.
I fried a barnett kevlar clutch in 3 dragstrip runs...the friction material just came right off the metal plate...I sent them back to barnett and got a replacement from them and gave them to a friend of mine, would never use them again...although it may have been just a bad set, it wasnt worth taking the chance of having one let go again, under wide open throttle with the juice on..I had too much money invested into that motor to take a chance........stock friction plates are the best (at least suzuki is, thats why i asked larry about the other manufactorers clutches)
 
#15 · (Edited)
I am not implying this is your riding style but just an FYI; a lot of people like to save brakes by using the downshifting to slow down. This is perfectly ok, BUT only if done in a smooth yet speedy way, It is not good to drop down a couple of gears at a time and just pop the clutch out you would be a the risk of wheel hop. You also don’t want to do a long drag it out relese, this puts a reverse sonario on "riding the clutch" So in return the brakes you saved went into a premature clutch wear bill. With practice and finesse you can actually save both. Clutches don’t only wear out taking off and up shifting. Long drug out "brake pad saving" downshifts eat them up too. Just :2cents: more.
 
#16 ·
GsxrJack said:
I fried a barnett kevlar clutch in 3 dragstrip runs...the friction material just came right off the metal plate...I sent them back to barnett and got a replacement from them and gave them to a friend of mine, would never use them again...although it may have been just a bad set, it wasnt worth taking the chance of having one let go again, under wide open throttle with the juice on..I had too much money invested into that motor to take a chance........stock friction plates are the best (at least suzuki is, thats why i asked larry about the other manufactorers clutches)
Never had a problems with mine. Thats crazy tho, three runs huh. What kind of springs did you have?
 
#17 ·
twisty said:
Never had a problems with mine. Thats crazy tho, three runs huh. What kind of springs did you have?
ya, like i said it might have been just a bad batch that the friction material didnt stick right to the plate cause it wasnt a wear out thing but when i took the clutches out the material just feel out also, they really got hot and the material just let go..(pain in the arse to clean up that mess in my motor also) ....but once is enough for me....

i also at that time had the stock gsxr1100 basket that used one single washer looking spring and i use to double it up to make it beefier but it really wasnt a great setup for dragracing,,,so i changed the basket to a gsxr750 one that allowed me to go with the 5 or 6 springs/bolts and i went with heavy duty springs with spacers in it to beef it up even more, this helped me from eating up clutches a lot , but i still went through them like candy...this motor and my launching style was rough on clutches and rear tires :bonk: i was getting ready to order a lock up clutch set up and the motor let go... :cry:
 
#18 ·
and back to you gasman, it just sounds like the beginning of a clutch getting ready to start slipping more and more....get some freeplay in the clutch cable and see if the problem goes away...if not, then its time for a new clutch, no biggie, youve gotten your moneys worth out of that clutch anyways....

the best way to test a clutch imo is to get going around 40 mph and put it in 5th gear and go wide open...thats the hardest situation the clutch will see and if its on its way then it will slip.... :2cents:
 
#19 ·
ok ok... calm down people...that was a late post typo! There is about 1/4" of free play... I guess in my sleepless mind.. I meant no excessive freeeplay... I've tried every combo of WOT in every other gear... and NO slippin other than that 4th gear....

I really wish there was more signs of it to make me feel better about the clutch replacement... being that there is no other signs it makes me wonder...

If I do have to replace the clutch I am wondering... does most of the factory clutch kits come with a new basket?
 
#20 ·
In 99.9% of clutch replacemnets the Basket is not necessary to change unless you have waisted it. A new clutch pack and metals and even Heavier springs and Oil change. would be all you need. (springs optional) And a case gasket unless yours is reusable. Dunno.
But the basket is useally good for the life of the bike.
 
#21 ·
OK..that sounds good... If I decide to open it up... will I be able to tell if the plates are good and the springs are tight... is there something I can do to verify it?
 
#22 ·
You could get real tech like and find the correct thinkness spec and mic it. You may or may not see the difference in the clutch pack thicknes. You see Even at a little clutch wear, the spring ratio changes. So by replacing the clutch pack and metal plates and gaining say .005 to .010 of an inch back in your clutch pack overall thickness, this in turn reloads the springs. You see of course you are aware that any spring gets tighter as it is compressed. So a new unwore clutch kit will bring your spring rate back up. But you can buy heavier rated or longer springs as a performance up grade. It is best to always get a bowl or something that you can lay the entire clutch plate fibers only in and submerge them in THE OIL that will be used in the bike for one night at least. This allows your clutch pack to swell and NOT have a dry start on them when you run. Installing them wet is the best way. Installing them dry is bad, some spots in the middle can stay dry for days. Just a tip.
I now to some I dont have much credabilty on this site but I am Not BY FAR new to bikes just because I am a new name to this site. 25 years Bike experience. I havent done them all but I will help enyone any where I can.

Good Luck.
 
#26 · (Edited)
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