Kx450 ignition probs SOLVED

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5/30/2018 3:58 PM

Finally got my bike back from the shop - its been 5 weeks and the guy couldnt figure it out. Bike will run and turn off like you hit the kill switch.

Ive done ohm & continuity tests on the stator, kill switch, @ crankshaft sensor. All checked good. No shorts or anything. Have a new fuel pump & tip over sensor - those should be good.

Next i started checking for spark, and i noticed it took about 20 kicks to get the spark tester to light up. After the kicks it would spark strong everytime.

Any ideas? Weak stator? Bad capacitor? Whatever it is seems like its not strong enough to get a fast charge & hold it for the bike to run.

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5/30/2018 7:17 PM

Have you done an ohms test on the coil?

Paw Paw

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5/30/2018 7:23 PM

Sounds like capacitor. You can unplug green connector by left radiator. Wire in a 12v dc battery to side of plug that stays on frame. If it starts easy, your capacitor is bad.
If still a problem, borrow a friends ecu. I had a stock one go bad on a 18 recently that intermittently worked.

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5/31/2018 6:40 AM

I still have the coil, & water temp sensor to check resistence on. Ill report back when i do that after work.

Ill have to go get a 12v bike battery from walmart tomorrow. Looks like ill need to make up some harnesses with alligator clips to measure all of the input/output voltages. I definitely want to rule out all of the sensors before i buy an ecu

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5/31/2018 7:35 AM

Just jump it to your car. No need to buy battery. Make sure polarity is right

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Follow me on twitter @williamsmotower if you're a gearhead you'll like the pics, and ask me tech tips.

5/31/2018 3:35 PM
Edited Date/Time: 5/31/2018 4:11 PM

My coolant sensor resistence is 1.53 kohms @ 90 degrees.

Service manual says 1.13k ohms at 104 degrees.

Edit: after heating the sensor to 104F, it reads 1.20 k ohms. Manual calls out a tolerance of 0.095 k ohms. Should be in spec

Photo

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5/31/2018 4:45 PM

Coil resistence test results...
My readings:
Primary: .8 ohms
Secondary: 13.78 k ohms

Kawi spec:
Primary resistence: .28-.38 ohms
Secondary resistence: 7.65-10.35 k ohms


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Photo

Tomorrow at work ill have our electrician confirm this as a bad coil. Hes got killer tools.

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5/31/2018 5:58 PM

The coil will break down when it gets warm. ( The primary reading will reduce.) When that happens you loose spark until it cools.

Paw Paw

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5/31/2018 6:12 PM

About how long does it take to break down?

My service manual is saying if theyres ignition coil trouble, it will shut off the coil.

That would explain why the bike dies as if you hit the kill switch. Also explains why theres no spark until you kick it a lot.

With the added resistence, theres not enough voltage in the capacitor to provide a spark. And since heat seems to raise the resistence, it only gets worse until it shuts off or the capacitor is out of juice.. sorry random thinking. Likely will order a new cap & coil tomorrow.

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5/31/2018 7:03 PM

Also be sure your mounts are 100% clean.

Paw Paw

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6/5/2018 3:59 PM

Wanted to update this and get some feedback. I installed a new coil, cap and kill switch - havent tried them yet. Currently reviewing my motor before i put the tank back on. I noticed my marks on my cams arent perfect with the gasket surface. Exhaust is lined up, yet the intake is 1/2 to 1 pin off(higher than the surface). HOWEVER, it is in time. Looks like a stretched chain or one not under tension. My prox cam chain has 5-10 hours on it so i wouldnt think its stretched already. If i push up and down on the chain between the cams, i get about 4-5mm of play. I want to think it used to have zero up and down movement a while ago. My thoughts is a weak tensioner. Is that possible? I thought they work or they dont. Its not bad enough to cause it to jump time, but 1/2-1 pin off can definitely cause stalling and hard starting

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6/5/2018 6:46 PM

Sounds like your cam chain has worn out.

Paw Paw

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6/6/2018 1:08 AM

Paw Paw 271 wrote:

Sounds like your cam chain has worn out.

Paw Paw

Guess ill buy a new oem one with a tensioner. If its toast in less than 10 hours that’ll be the last time i buy anything from prox.

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6/6/2018 3:20 PM

That's how timing looks on Kaw 450's. A lot of people time them wrong, yours is correct.

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Follow me on twitter @williamsmotower if you're a gearhead you'll like the pics, and ask me tech tips.

6/6/2018 4:34 PM
Edited Date/Time: 6/6/2018 4:35 PM

The timing marks were weird from how it was sitting - i dont think theres a chain issue. Rotated the motor a couple times and it looks good.

Have a question to run by you guys. I havent been in a position where ive had cam chain guide wear issues before. Right now the guide on the intake side is visibly worn. Ive noticed that the chain is hitting the cylinder head up by the gasket surface. Either the guide is flexing & allowing the chain to get loose(as shown by the dark marking on the wall of the head) or the tensioner is weak. Im replacing the guide, chain, and tensioner regardless, but would like some input just to learn. Can a bad guide cause stalling issues or am i trying to blame the motor?Pics below of the guide & where the chain hits the head.Photo
Photo

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6/7/2018 8:16 AM
Edited Date/Time: 6/7/2018 8:19 AM

absolutely, kawi chain guides are just garbage all around and when the guide wears you lose tension. also, i’ve had the exact same issue on my kawi 250f as far as the tensioner/cam chain guide wear. Ironically i stretched a pro x cam chain as well but have had very good luck with them since. However in my experience i figured it was just the bikes age.

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6/7/2018 9:09 AM

Thanks for the input. I might take a die grinder and clear that out a little more. My chain hitting the head isnt cool lol

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6/9/2018 11:00 AM

Ok new coil, kill switch, cam chain, tensioner, guides, plug cap, spark plug. Bike still misfires and stalls. Seems to get worse as it heats up. I think im down to 2 options.. stator or capacitor.

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6/9/2018 2:59 PM
Edited Date/Time: 6/9/2018 3:02 PM

well guys, after $1000 in parts, and having a shop look at it, turns out the problem was dirt inside the harness plug to the ecu. Sprayed electrical cleaner in it and put dielectric grease on it. starts in 2 kicks and runs like a champ.

Having this misfire/stalling issue happen all the sudden(on a jump landing), i would have never guessed the plug on the ecu. It only came to mind after desperately going through every inch of wire and plug, and checking all the sensors.

The bike was at the shop for 5 weeks. Ive had it back for almost 2 now. Had a TON of time to learn about electrical diagnostics and all that

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