Author Topic: Intermittent engine shut-down when downshifting  (Read 673 times)

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Offline Don

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Intermittent engine shut-down when downshifting
« on: May 06, 2018, 02:00:16 pm »
I just picked up a 2003 C10, 29K miles.  Initial shakedown revealed the engine will intermittently stall on downshift.  Not able to consistently repeat at any road speed, RPM, or particular gear.  Squeeze and hold the clutch and the tach will simply bottom out to zero.  Not every time.  Sometimes.  Given no maintenance records from previous owner, took the bike to the local Kawasaki dealer (already a long-time customer) and had them do a complete 0 - 30K maintenance.  Found a cracked coil pack.  Replaced both.  All specs checked out.  Got the bike back and, ............  Again.  On the ride home the intermittent stall still there.

Anyone else have this happen, and, any clues how to fix?


Offline RWulf

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Re: Intermittent engine shut-down when downshifting
« Reply #1 on: May 06, 2018, 03:43:14 pm »
DON, just a guess, is the idle set at 1100 rpm.
And who is your dealer in Michigan ?

Offline Harry Martin

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Re: Intermittent engine shut-down when downshifting
« Reply #2 on: May 06, 2018, 03:55:36 pm »
Makes no sense.
"all specs checked out", would imply idle is good.

Some questions:
1. When engine dies, do lights, horn, dash still lightup/work?
2. Put bike on centerstand and run bike in 1st gear. What happens when you bump/nudge side stand?

If bike under load, when shifting (poorly) -does a slight shift in forward momentum cause an electrical open/short somewhere in the ignition system? Loose ground?

The only time my C10 died on a ride was when I accidently hit the kill switch, forgot to put up side stand, or the J-Box had a cracked solder connection.

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Offline works4me

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Re: Intermittent engine shut-down when downshifting
« Reply #3 on: May 06, 2018, 07:51:35 pm »
Pull in clutch, engine dies. Clutch switch?

Offline Daytona_Mike

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Re: Intermittent engine shut-down when downshifting
« Reply #4 on: May 06, 2018, 09:35:18 pm »
sure sounds like the ground path  to the coils is intermittent   but you would think that can be replicated sitting still.
You need the schematics if dont already have them. 
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Offline MAN OF BLUES

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Re: Intermittent engine shut-down when downshifting
« Reply #5 on: May 06, 2018, 09:54:28 pm »
Pull in clutch, engine dies. Clutch switch?

Bingo

Remove the switch, and blast it out real good with WD40, and reinstall it...
Also, check to make sure the black/yellow ground wire that attaches to the left side coil mounting bolt, under the tank, is in good shape, and not frayed or damaged, or otherwise poorly grounded... tach drop is an indicator, but the stall may be from either the switch, or that wire.

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Offline Harry Martin

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Re: Intermittent engine shut-down when downshifting
« Reply #6 on: May 07, 2018, 12:18:16 am »
Pull in clutch, engine dies. Clutch switch?

Bingo

Remove the switch, and blast it out real good with WD40, and reinstall it...
Also, check to make sure the black/yellow ground wire that attaches to the left side coil mounting bolt, under the tank, is in good shape, and not frayed or damaged, or otherwise poorly grounded... tach drop is an indicator, but the stall may be from either the switch, or that wire.

Okay...this is news to me.
I looked in the C10 schematic and did not see a clutch switch.
What am I missing? Is there another name for it? What does it control?

Thanks.
Harry in Wild and Windy Casper, WY - 1986 Vintage "Silverdammit" - 2015 "Greendammit"
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Offline who me?

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Re: Intermittent engine shut-down when downshifting
« Reply #7 on: May 07, 2018, 12:56:42 am »
Pull in clutch, engine dies. Clutch switch?

Bingo

Remove the switch, and blast it out real good with WD40, and reinstall it...
Also, check to make sure the black/yellow ground wire that attaches to the left side coil mounting bolt, under the tank, is in good shape, and not frayed or damaged, or otherwise poorly grounded... tach drop is an indicator, but the stall may be from either the switch, or that wire.

Okay...this is news to me.
I looked in the C10 schematic and did not see a clutch switch.
What am I missing? Is there another name for it? What does it control?

Thanks.
Starter lockout switch maybe?
I have no idea about anything.
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Offline Harry Martin

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Re: Intermittent engine shut-down when downshifting
« Reply #8 on: May 07, 2018, 01:09:04 am »
I see no switch controlled by the clutch lever.
I have an 86' so maybe I'm lacking info on this as I have older manuals.
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Offline Harry Martin

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Re: Intermittent engine shut-down when downshifting
« Reply #9 on: May 07, 2018, 01:29:52 am »
I see no switch controlled by the clutch lever.
I have an 86' so maybe I'm lacking info on this as I have older manuals.

Okay, just spotted it, the Starter Lockout Switch is controlled by the clutch lever. However, that should not stall the engine from what I see.
That just prevents the starter motor from turning if the clutch is released while in gear, does it not?
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Offline Harry Martin

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Re: Intermittent engine shut-down when downshifting
« Reply #10 on: May 07, 2018, 03:09:14 am »
I have reread the C10 service manual.
The Ignition System Troubleshooting guide is where I think the answer lies. But it is not easy to understand.

In my manual, it's page 15-21.

Big K says start at the IC igniter. Well, it's a hairball of a test to confirm an intermittent problem.

If it was me, I'd start looking at the sidestand switch. The sidestand switch routes a low current signal to/from the IC igniter.
The IC igniter will kill the motor if it thinks the side stand is down, which means, it would not take a lot of dirt to create a low current signal to ground.
I would make sure there was no dirt or crud to fake out the igniter. Same with the kill switch. I believe these are logic signals that the IC igniter is constantly monitoring their status. If that doesn't do it, then I'd pull the IC igniter and follow the test procedure to the letter. The manual wants us to start with the IC igniter, but the other two switches are far easier to test and inspect. If that's not the problem, then the IC igniter, then the pickup coils. But, I would also be inspecting that J-Box for solder fractures. I suspect vibration is causing a make/break connection while shifting.

 :popcorncouple: :popcorncouple: :popcorncouple: :popcorncouple: :popcorncouple: :popcorn:
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Offline JPD

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Re: Intermittent engine shut-down when downshifting
« Reply #11 on: May 07, 2018, 12:24:44 pm »
The clutch switch in combination with the side stand and neutral switch is what will shut off the bike when you try to drive away with the side stand down. They are also in the starting circuit for control of the starter relay so you don't turn the starter with the bike in gear and clutch lever out. Both the clutch and side stand are subject to wear and or dirt accumulation. Think about how many times the clutch is activated on every ride. They are made of plastic and I have had them worn internally and also the plunger has broken.
The way you described the fault it is when you are pulling the clutch in and the bike starts running again when you let the clutch out. That is the Item you are moving so I would look there first.

Offline connie_rider

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Re: Intermittent engine shut-down when downshifting
« Reply #12 on: May 07, 2018, 01:27:20 pm »
Don, "first" we need a bit more info from you?
Please answer their questions .

I agree with them, may be in that circuit.
Do a  WD-40 trick on the Clutch and Side stand switch.
Starting with the clutch..

But, the fact that it "sometimes" happens when your decelerating makes me thing you may have an intermittent short or open circuit. 
MOB has a good point. Start with, check the ground at the coils. Including cleaning the ground/contact area of the coils.

Lastly, clean/inspect the plug's at the front of the bike and inspect wires near the triple tree's for a short..
May have a bare wire or poor contact in that plug.

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Offline Daytona_Mike

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Re: Intermittent engine shut-down when downshifting
« Reply #13 on: May 08, 2018, 04:49:57 pm »
If I remember correctly there are 3 ground paths for the ignition circuit. One of the three has to be present or the engine stalls.

Clutch lever switch   when the clutch lever is in  the  out position (hand is off)  the ground path is lost. When pulled inward - that adds a ground path

Neutral Switch- as soon as the bike is put in gear that ground path is lost.

Kick stand switch - When the Kick stand is up- This the only ground path left when your riding and the clutch is lever is out so this one switch would be the MOST important.  When the kick stand is down- no ground path

So for example:
 Clutch lever held in with  engine running  and the bike is in gear and you have  the kickstand down. The one and only ground path left  is your clutch lever switch- (held in) then you  let the clutch lever out and the engine dies- you  just lost your last ground path.  Doe this make sense?


The above  does not address 12 volts to the ignition system   which if lost will also stall the engine. On my old C10 sometimes I would shift and  the engine would die for good. That was because my foot had worn a hole in the main harness and caused an occasional short - blowing a fuse.

I hope this helps.  Please correct me if I am wrong.
Normally aspirated engines have perpetual turbo lag
2000 Red C10 1052 kit
2008  C14 Silver Dammit Full AreaP- Flies are put back in SISF_Flash
2011  KLR650   688 piston ported and polished
2011  KTM 530    This thing is FUN!!

Offline Don

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Re: Intermittent engine shut-down when downshifting
« Reply #14 on: May 10, 2018, 06:47:08 pm »
First, thanks to all for the great feedback.  Much appreciated.  Problem solved.

Quick update for those interested in how it turned out:

I finally got out for an extended flog on the new (old) baby.  Scratching my head and thinking, this is a 15 year old bike with 30K on the clock.  What if ...... the previous owner rode her for a couple of years and then let her sit?  Other clues: Certified tech (Scotts, Coopersburg PA) just went over everything head to toe.  Electricals checked out (after replacing coils).  (I know - electricals are tricky, but, it's a clue and says look somewhere else, first).  Suspecting a not-so-happy set of carbs.  So, started with a couple of ounces of carb cleaner in the tank.  During the ride and getting more bonded with the bike, noted the idle a tad low at ~800.  Also noted during riding if I held the clutch, the tach needle would come down to ~500 then coin-toss whether it would stay lit or die.  As RWulf suggested, and with the bike thoroughly brought to temp, dialed in +300 additional idle RPM to 1,100.  After ~100 miles of letting the Connie stretch her legs, running fresh fuel and carb cleaner, and dialing up a bit of idle RPM, the problem seemed to be gone by the time we got back to the barn for the night.

Thanks, again.  Ride safe.  They're nuts out there!

Don

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Re: Intermittent engine shut-down when downshifting
« Reply #15 on: May 10, 2018, 07:32:25 pm »
 "BE CAREFUL" with auto carb cleaner!! :-[  Can ruin slides and rubber diaphragm. If diaphragm is ruined you carbs are toast!! At best a whole lot of $$$!!
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Offline MAN OF BLUES

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Re: Intermittent engine shut-down when downshifting
« Reply #16 on: May 10, 2018, 09:17:19 pm »
800 rpm, is more than a "tad bit" low... its 20% lower than the "normal" specd idle..
Never asked, I should have... and when you are riding, and pull the clutch in, and it drops to 500rpm, its because the oil pump and engine itself is placing a demand on "idle speed".. so it drops further.

Setting idle at 1100-1000 min, works fine, simple fixes are best.. :great: :great: :great:

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