KDX starting issue

[craig.hodges]

Had the key break on the flywheel. Replaced it, put it back together. Now it seems the timing is off, kick start fires back. It started once, but not long enough to see how well it ran. Any thoughts?



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[pumpguy]

Craig,

Unless you had the stator off and put it back in a different location, the timing shouldn't have changed.

What is the condition of the tapers and keyways on the shaft and flywheel?

In reality, the key's primary function is locating. It's the tapers that do the actual holding. Most likely scenario is the flywheel was loose and caused the key to fail. Had this happen to me once, and the flywheel hub split at the keyway. I now use that flywheel as an anchor for my fishing boat.

If the tapers are damaged, your flywheel may not be running true (concentric) with the stator pole shoes.

I would check for spark first. If you get a nice snappy blue spark when you kick the engine over, then I would think you have a timing issue.

[Tyl3r]

I wonder if the flywheel was banging around in there and damaged something else. Did you pull the flywheel out and inspect everything before reassembly? Maybe it nicked the stator or an output wire. Id check around in there too

[SS109]

Good info so far. Sounds like the timing is advanced too much. The readily apparent culprits are either the magnet or the hub moved in the flywheel.

However, keys normally (operative word normally) don't just shear unless something causes them to. Have you done any work to the bike (other than replacing the key) recently? Does it still have the factory stock piston? KDX220 factory pistons are notorious for shattering their skirt without warning and for no reason other than their poor design. A piston skirt breaking, and momentarily lodging itself between two surfaces, can cause a key to shear. Also, another possibility is detonation. When severe detonation occurs it can destroy bearings, the piston, the rod, or shear the woodruff key. Also, do you have a spare ignition coil and/or CDI to swap in to eliminate them as the problem?

[craig.hodges]

I did put a new coil on the bike, and then rode 1100 miles. I next did some single track in mud, that is when it died. I did not use a torque wrench when putting the flywheel on and suspect that is what caused my current issue


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[craig.hodges]

I used some valve seating compound when I just put it on and they mated nicely


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[craig.hodges]

Thanks for the replies


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