Author Topic: Clutch issue - double bump - Star springs? - Solution posted!  (Read 586 times)

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Offline Jerdurr

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Clutch issue - double bump - Star springs? - Solution posted!
« on: September 22, 2019, 01:21:30 pm »
Hey there folks...so I went on an 800 mile trip on my bike, a 2012 concours 1400 with 28K miles on it; on the first 300 miles, I was hitting the twisties under hard acceleration and rev matching at the curves. When the curves were done, I felt that it developed the annoying "double bump" on the clutch when engaging under acceleration (if I ride it like a grandma and wait half a second after I changed gears and before I release the clutch, the bump is not there). I was able to continue the trip, do more twisties, but of course babying the clutch, and made it home safely. It doesn't feel like the clutch is slipping or other signs of it being worn.

To be perfectly honest, I do like to ride it hard, more like a sportsbike than a tourer.

For those that wonder, I was running T6 Rotella on it, fairly fresh.

I read the different posts and it seems to be very compatible with the star springs breaking. I plan to do the work myself. I have the following questions:

1) Considering the low mileage on the bike (28K miles), the lack of clutch plate wear related signs, but also that I ride it like i stole it most of the time, should I change the plates, Nut, springs and gasket while I'm in there?

2) If you say I should change it, should I get a Barnett clutch, or just go for regular mama kawi clutch parts?

3) 'm located in Canada, any suggestions from my fellow Canadians, considering shipping adds quite a chunk of change to the final cost?

Thanks guys!!b :c017:
« Last Edit: September 26, 2019, 05:26:19 pm by Jerdurr »
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline gpd323

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Re: Clutch issue - double bump - Star springs?
« Reply #1 on: September 22, 2019, 03:13:23 pm »
Such low miles I would replace the 4 SS's and the nut and call it a day. I had a shop do mine recently along with the valve inspections.

2 of my SS's were broken.

Yes, if you baby the clutch up/down shifting the double bump is muted.
Greg Downing
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Washington State

Ride while you can.

Offline gpd323

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Re: Clutch issue - double bump - Star springs?
« Reply #2 on: September 22, 2019, 03:14:56 pm »
At Partszilla the springs are less than 6 bucks a set, add the nut and its under 8 bucks for the shipping costs.

Yes get the gasket too.
Greg Downing
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Washington State

Ride while you can.

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #3 on: September 22, 2019, 03:15:22 pm »
Such low miles I would replace the 4 SS's and the nut and call it a day. I had a shop do mine recently along with the valve inspections.

2 of my SS's were broken.

Yes, if you baby the clutch up/down shifting the double bump is muted.

Cool, I'll just do that. I wonder, is it that hard to remove that stupid nut? What is the issue...? is it torqued too tight? Can it be done with a regular socket, or you actually need the special tool from Mama Kawi?
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline gpd323

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Re: Clutch issue - double bump - Star springs?
« Reply #4 on: September 22, 2019, 03:18:33 pm »
its a 24mm nut, mine looks to have some scoring on the face of the nut where the socket would impact the nut to loosen it, so I'll guess an impact was used.
Greg Downing
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Washington State

Ride while you can.

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #5 on: September 22, 2019, 07:05:53 pm »
its a 24mm nut, mine looks to have some scoring on the face of the nut where the socket would impact the nut to loosen it, so I'll guess an impact was used.

It is NOT a 24 mm nut, I just bought a 24mm socket and doesn’t fit at all.

Does anybody know what size socket i need for the clutch nut?
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline gpd323

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Re: Clutch issue - double bump - Star springs?
« Reply #6 on: September 22, 2019, 07:11:09 pm »
Sorry Mate, its a 27mm.

BTW: The right black side lower plastic panel can come off on its own without taking that whole side off to get at the clutch cover
Greg Downing
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Washington State

Ride while you can.

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #7 on: September 22, 2019, 07:18:19 pm »
Sorry Mate, its a 27mm.

BTW: The right black side lower plastic panel can come off on its own without taking that whole side off to get at the clutch cover
FML... I gotta go back to the store now...

No worries bud, I appreciate you trying to help!
I removed all of it, I didn't want to break those stupid plastic tabs.
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #8 on: September 23, 2019, 12:12:46 am »
27mm socket works... tried with my electric impact gun, no luck. How the heck do I remove that stupid clutch hub nut?
I don’t have the specific tool to hold the clutch.

I did wedge a piece of metal and put the shifter in 1st gear, but no luck.

MOB? Ted? Matt? Anyone?!?
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #9 on: September 23, 2019, 01:59:17 pm »
Quick update. My friend Steve brought me his compressor, and even with the air impact wrench the nut is still not breaking loose.
Got me a breaker bar and a piece of metal tube for longer leverage, will attempt later today with the locking tool in place. Quick question: how does the clutch locking tool works? Never used one before. I ordered the EBC circular one.

Tried attaching A picture to show yet another star spring sheared off, but 350kb is way too small so my photo got rejected.
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline mgoodrich

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Re: Clutch issue - double bump - Star springs?
« Reply #10 on: September 23, 2019, 02:01:47 pm »
I needed to use a 3/4 inch air impact wrench on mine. That was on my C10. I also had the clutch locking tool installed.

I borrowed it (impact wrench) from my dealer at that time.

I fortunately have a large air compressor that could run it.

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #11 on: September 23, 2019, 02:09:45 pm »
I needed to use a 3/4 inch air impact wrench on mine. That was on my C10. I also had the clutch locking tool installed.

I borrowed it (impact wrench) from my dealer at that time.

I fortunately have a large air compressor that could run it.
I'm gonna try with the clutch locking tool later on today. I already ordered the springs and nut. If that doesn't work, I'm at a loss!  >:(
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline gpd323

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Re: Clutch issue - double bump - Star springs?
« Reply #12 on: September 23, 2019, 02:50:42 pm »
its torqued at 100 foot pounds. My electric impact has a 250 foot pound rating, I have taken drive sprockets off that are torqued at 140 foot pounds easily.

Get a beefier impact, or rent one at a Home depot or other place? The FSM shows a clutch holder tool when removing that nut.
Greg Downing
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Washington State

Ride while you can.

Offline MAN OF BLUES

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Re: Clutch issue - double bump - Star springs?
« Reply #13 on: September 23, 2019, 09:57:12 pm »
27mm socket works... tried with my electric impact gun, no luck. How the heck do I remove that stupid clutch hub nut?
I don’t have the specific tool to hold the clutch.

I did wedge a piece of metal and put the shifter in 1st gear, but no luck.

MOB? Ted? Matt? Anyone?!?

I have not removed a C14 clutch yet, but I'll share what I've learned doing multiple c10's...
On the C10, I actually used an "INCH" SAE socket, which was "slightly tighter fit" on the nut, and prevented slipping off..
With my wife sitting on the bike, and shoving a 2 x 4 thru the rear wheel, thru the swingarm, and having her apply the rear brake FULLY... I could easily break the nut free using a 1/2" drive breaker bar (2 foot long, with a piece of pipe slipped on as a helper)...

For the C14, you can also use a HEX socket (not a 12 point one), in SAE size, 1-1/16" it also will fit snugly on the nut.(more so than the 27mm will).
I highly suggest that the socket be modified slightly, when doing either a C10, or a C14, by "dressing the open end" of the socket, by grinding it in a flat manner, on a belt sander, the open end, to fully remove the internal chamferred end of the "HEX" untill the shortened socket has no more chamfer, and allows a full hex contact.

I would assume jamming a 2 x 4 thru the rear swing arm assembly, thru the rim, bike in first gear, and having an assistant sitting on the bike pressing the rear brake, should allow the breaker bar and cheater pipe method for removal. I would not attack it with a Impact using this method tho, and you may damage a gear, a firm and strong push with the breaker bar will work. Use your foot.

best of luck
« Last Edit: September 23, 2019, 10:00:32 pm by MAN OF BLUES »

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Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #14 on: September 23, 2019, 11:14:25 pm »
Awesome.
Thanks MOB!
Finally got that stupid nut lose. 2x4 through the wheel, in 1st gear, with the locking tool and a breaker bar plus a steel tube to extend the leverage did the trick.

I hope I didn’t damage the dogs trying to remove it with the impact gun.

Now waiting on parts to arrive in Wednesday, will put it back together and will report back how this story ends.

Thanks guys!
:-)
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline Jerdurr

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Re: Clutch issue - double bump - Star springs?
« Reply #15 on: September 26, 2019, 05:25:41 pm »
To anyone going through the same issue, my bike developed the double bump at 28K miles. Granted, I ride it hard, but nothing out of the ordinary. Plenty of rev matching down shifting in the curves, never dump the clutch for wheelies or any other monkey business. I knew it was one of the stupid star springs.

Long story short, I've attached here some pics of what broke (a star spring).

I went ahead and ordered the 4 springs (2 different part numbers, you will need 2 of each), the gasket even though mine seemed pretty good I am a bit obsessive so I changed that too; the clutch hub nut - I tried removing it with an electric impact wrench, no luck. Then tried a compressor impact wrench, also no luck. At this point I was starting to feel disheartened.

(If you need to do this job, I strongly suggest to follow MOBs advice on an earlier post here, and also to use a clutch locking tool, such as the one in the picture. That made the job a whole lot easier).

What ended up working to remove that nut, was sliding a 2x4 in the rear wheel, to lock it from spinning, putting the bike in first gear (DO NOT DEPRESS THE CLUTCH LEVER WHILE THE CLUTCH IS DISASSEMBLED), using the clutch locking tool (always turn the clutch counter clockwise to align it with the tool - otherwise you are turning the engine in the contrary direction to which it should turn), a breaker bar and a tube to extend the leverage effect. As my friend Steve said, gotta love physics.

Once the nut is removed, you can access the star springs. Make sure to install them following the microfiche diagrams (the ones online have more detail than the one on the FSM).

Once done, tighten the NEW nut to 100 ft/lbs of torque, reinstall everything, install new filter and reload oil if you removed it in the first like I did, and you should be good to go.

Feel free to DM me if you have any questions.
Best,

JD

--Harley Davidson is king when it comes to turning gas into smoke, without the outcome of power--

Offline gpd323

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Re: Clutch issue - double bump - Star springs? - Solution posted!
« Reply #16 on: September 26, 2019, 06:29:47 pm »
Just one broken huh? Thanks for the updates.
Greg Downing
Beautiful Downtown Spanaway
Washington State

Ride while you can.

Offline connie_rider

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Re: Clutch issue - double bump - Star springs? - Solution posted!
« Reply #17 on: September 26, 2019, 06:47:24 pm »
Just saw this.
Glad you got it done and thanx for posting what you went thru.

Better late than never I have a thought or 2.
   I haven't had to go into a clutch in years.
     When I did, (as I recall) I would sandwich a rag between the clutch gear and input gear to add resistance, put it in gear,
     and stand on the brake.

NOTE: Any higher gear would be better than using first gear because of the gear ratio.
           ie; Takes less force to keep the rear wheel from rotating.

Ride safe, Ted
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Offline MAN OF BLUES

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Re: Clutch issue - double bump - Star springs? - Solution posted!
« Reply #18 on: September 26, 2019, 09:04:32 pm »
Just saw this.
Glad you got it done and thanx for posting what you went thru.

Better late than never I have a thought or 2.
   I haven't had to go into a clutch in years.
     When I did, (as I recall) I would sandwich a rag between the clutch gear and input gear to add resistance, put it in gear,
     and stand on the brake.

NOTE: Any higher gear would be better than using first gear because of the gear ratio.
           ie; Takes less force to keep the rear wheel from rotating.

Ride safe, Ted

I hear what you are saying ted, and many years back, people would do similar to "lock up" that drive, but it can result in "cracking" the fragile case if too much force is used... seen it a few times.. it tends to "force" the shafts apart, in a manner that goes sky high on stress in a direction stress normally isn't seen during normal operation.

also, the comment about using a higher gear seems like it would be viable; but again, looking at the actual shaft and gear mating, thee "strongest" mating occurs when in first gear; as it doees not rely on "moving gears, or dogs in mesh" for the resistance strength.

The first gear on the input shaft, is actually machined on that shaft itself, on the end of the stack, and also the output gear(even tho that gear does move), resides outboard on it's shaft, right next to a support bearing, in both cases... gears 3 thru 6 all move back and forth, along the shaft, unsupported; I consider them to be "fragile" in comparison to first gear when mated.
I think pretty much all of the "broken gears" we have seen so far on this bike, have been the higher gears, 3 thru 5, which shows how fragile they actually are when subjected to "severe" loads...
Of course, none of that really comes into play if using the "clutch locking tool", as that does the lockup, hen the arm is against a fixed point like a footpeg or bracket.

I replaced so many KZ clutches when I was racing, I simply stacked a couple "old bad" steel and friction plates, like 3 of each, and drilled holes in them, and attached a robust "lever arm" to my home made tools...

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...