Bike won't start

[Alpinestars2785]

Hey guys, I was riding my bike yesterday for a little while it stalled on me and sounded like the plug fouled and I couldn't get it to re-fire, even after i tried a new plug.  I had a BR9IEX plug in it because I wanted to try an iridium plug and see how it performed.  I took the carb off today and cleaned it and emptied the bowl and couldn't get it to fire for the life of me.  It's got spark and fuel and when I open the throttle a little while kicking it will back fire a little every so many kicks.  I'm gonna take it to my buddies bike shop tomorrow and have him look at it but i thought i'd see what you guys thought first.  Thanks!

[dcollins4328]

It might be your stator. You might have a WEak spark.

[Alpinestars2785]

I'll take a look at it, I just actually replaced the stator and fly wheel the other day.  My bike had a flywheel for a KDX or KLX 250 that had a weight welded to it and the stator plate was very dirty inside the cover.  I think it was because the the guy who had my bike previously put that flywheel on there and had to make a gasket that was way thicker in order to put the cover on, and it still wore down the inside of the stator cover and I'm pretty sure thats why it got pretty nasty inside.  So I just replaced the stator plate and flywheel with a stock one.  I'm gettin' it looked at today by my buddy at his shop so we'll figure it out i suppose, but thanks mentioning the stator plate!  I'll let you guys know whats up.

[Alpinestars2785]

Ok so I took it to my buddy and he checked the stuff out on it and it was doing the same thing, had spark, had fuel and after a few kicks it would backfire.  So my friend suggested that the timing might be off so we checked the stator plate and sure enough it was a little advanced.  So when i get home I change it back to stock on the middle reference mark and try to kick it again and after about 3 kicks it backfires.  So then I tried to retard the timing back to the rear reference mark and put it all back and tried to kick it and the same thing happened, backfire.  I'm not sure what it could be.  I'm going to try to replace the old ignition system that I removed and see if it will fire with that one on.  I can't think of anything else it could be.  Any help would be much appreciated.

[The Flyin Hawaiian]

While riding an enduro on my 86 KX 250, my bike backfired and stalled. I got it running, let the clutch out and the tire through a roost in reverse. The woodruf key sheared on the crankshaft and caused my problem(flywheel rotated). Since you said that the previous owner had installed a KDX flywheel, I would look at the that. Pull it and check the key.

[Alpinestars2785]

Thanks man, I'll check that today.  I'll update tonight on the bikes condition.  To quote my friend..."we might have to just sets it on fire"

[hughes]

The flywheel and crank shaft are a tapered fit. The key way is just for proper alignment. If the key sheared make sure the surface of the crank and flywheel is not scored, then clean both parts with a contact cleaner or brake cleaner will work. You want to make sure the tapers are clean and free of any rust ,oil, grease or dirt.

[gowen]

Check the woodruff key first, also do a compression check. It might be a little low and just finished off on your last ride.

[don46]

Check your reeds, if you have a petal/s broken they won't start, I'm not talking a corner chipped, I'm talking broken petal. may explain the backfire as well.

[Jeeks]

Ditto for the woodruff key.  You'll have spark, just at the wrong time.  Happened to my friends Stihl demo saw.

[Alpinestars2785]

Good news guys, the problem has been solved.  It was in fact the Woodruff Key.  I didn't know how it was supposed to be seated in the groove when i replaced the flywheel and assumed that it was in there right when I put it back together.  It sheared off and made the timing all screwy, hence the back firing.  So i got another one installed and put it all back together and it started on the third kick and ran pretty good.  It's got a lot of oil in it right now from the many starting attempts i made so I'm going to ride it like I stole it tomorrow to try to get that cleaned out.  Anyway, thanks for all the help with my problem.  I'll update you more on it's progress when I have the top end rebuilt soon.