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MESSMAKER

2014 YZ450f No spark

14 posts in this topic

I just recently pulled the bike apart and upon completion I tried to start it and it would not fire. During the rebuild I also replaced the flywheel with the weighted GYTR model. I proceeded to check the plug to see if I had spark and sure enough there was none. I also checked a few different spark plugs and ended up with the same result. I went to the manual and did all the checks that it had and all the parts that are on that circuit, and they look to be good. I am at a loss right now so any help would be greatly appreciated.

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I really could use some help here guys. I'm sure someone has more experience with the ignition system,

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I really could use some help here guys. I'm sure someone has more experience with the ignition system,

If it worked before and doesn't now, I would suspect you forgot to plug something together. Retrace your steps and check everything you Touched of May have bumped.

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The capacitor plugged in?

Kill switch is working properly?

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Ok so I figured it out, when I replaced the flywheel with the weighted one I torqued it down to spec in the book and apparently it was not enought to seat the new fly wheel and it was just barely touching apparently thus shorting it out. I fully seated the flywheel and now I have spark.

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Ok so I figured it out, when I replaced the flywheel with the weighted one I torqued it down to spec in the book and apparently it was not enought to seat the new fly wheel and it was just barely touching apparently thus shorting it out. I fully seated the flywheel and now I have spark.

sounds about right. Glad it was a cost free fix. Ride on!!

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Ok so I figured it out, when I replaced the flywheel with the weighted one I torqued it down to spec in the book and apparently it was not enought to seat the new fly wheel and it was just barely touching apparently thus shorting it out. I fully seated the flywheel and now I have spark.

how tight did you torque it down?  i just replaced my flywheel with a gytr but i haven't tried to start it yet.

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how tight did you torque it down?  i just replaced my flywheel with a gytr but i haven't tried to start it yet.

I don't remember off hand but it was whatever the owners manual said to do. 

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how tight did you torque it down?  i just replaced my flywheel with a gytr but i haven't tried to start it yet.

When it was all said and done I'm not sure of the final torque value as I backed off the nut and put it back on a few times with a small electric impact then retorqued to factory value. Im curious if this is an isolated incident or if this is a common problem.  

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When it was all said and done I'm not sure of the final torque value as I backed off the nut and put it back on a few times with a small electric impact then retorqued to factory value. Im curious if this is an isolated incident or if this is a common problem.  

i think the factory value is 47 foot lbs if i remember off hand.  i did mine at that  and then took it back off the next day after second guessing myself if the woodruff key was in right.

 

when i took it off the flywheel popped right off when the nut was loosened and didn't need the flywheel puller or anything.

 

after making sure everything was correct i put just a little more torque on it..maybe 55 lbs.  i didn't want to go all out because if i stripped the threads id be in a world of shit.

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Ok so I just replaced my 15 with the gytr flywheel it started ran then died, I've taken it apart 6 times reported checking things even put stock flywheel back on won't start, I had to remove my subframe and ims tank to get to plug to check spark, and it has no spark, I'd sure like to know if I'm just not torqing it down enough? I'm at 47 lbs but like Ron Roberts said it comes back real easy

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One of the things that can happen while installing a flywheel is that the key gets dislodged while the flywheel slides on.  You can catch the leading edge and roll the key all the way up and out, in fact, or part way.  Different things happen depending on which condition you end up in.

 

If the key rolls all the way up and out, then there is no fixed reference for timing the flywheel to the engine.  That reference, of course, is necessary because the flywheel sends the trigger signal to the ECU for spark timing, and the marks on the flywheel are used for cam timing.  It has to be in the right  place.  Assuming your cams were timed right when you pulled the old flywheel, the only thing that would be off if you did this is the ignition timing, but without the key, the timing might be anywhere.

 

If, on the other hand, the key rolls part way out, depending on how much tilt it has, it can stop the flywheel from seating, even at 47 ft/lb, and at various distances from fully seated.  It can be a little or a lot out from where it belongs, and it can tilt.  Both these conditions can cause a variety of problems ranging from no spark until corrected to destructive breakage events in the generator assembly.

 

The right way to handle the installation is to position the engine so that the key is on top of the crank, then slide the flywheel onto the crank so the bottom surfaces of the flywheel and crank tapers touch as it slides on, testing for and accomplishing engagement with the key as you go.  Push it on as far as you can by hand, then slip a deep socket over the end of the crank.  The socket has to be of such size that it clears the crank on the inside without being big enough to contact the puller threads at edge of the flywheel center.  Tap the socket, preferably with a brass hammer (most any other kind works if you're careful) just hard enough to move the flywheel into place until it looks and feels squarely seated, then torque it to spec.  

 

Don't go crazy swinging the hammer; it is the crankshaft you're pounding on, after all.  Doing it this way makes getting the flywheel jammed part way on by a tilted key a lot less likely. 

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I have spark but won't start now, so I'm guessing after reading grayracer comment that I'm out of time, so if I takeoff the flywheel position crank with key on top and then put flywheel back on I should be ok??

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