1989 Kawasaki KX125 won't start - mega headscratcher.

[Gazdaman]

So I recently swapped this bike, and it came back because it randomly won't start.

I've had it for about 2 years, completely stripped it down and rebuilt it, it has been running absolutely fine.

So the guy says that he start it, pulled away, to the near top of first gear, about to change into second and it died. Instantly died, and rolled to a stop, no spluttering etc.


Today I've:


-Compression check: 120psi ~8.5:1 as it should be.
-Carb cleaned, idle and main jet both clear
-Fuel tap clear and working
-Spark nice and strong
-Reed valves in tact and seated properly
-Air filter clean
-Power valve appears free
-Exhaust taken off and checked for blockages (none).


I'm completely stumped, it should start! But it doesn't. It just doesn't seem to fire. I've even tried a nice big bump start, and it turns over absolutely fine, and kicks over fine. Just doesn't fire at all.

Good compression must rule out any major piston or barrel failure, good spark must rule out poor electrical connections on coil, pickup, HT lead etc.
Fuel is clearly getting into the carb, the jets are clear, no crap in the float bowl, I can smell fuel in the exhaust and out of the plug hole if I kick it over with the plug out.

All I can see it really leaving is timing. I did pop the generator cover off, and everything looks ok in there. But I suppose it could have sheared the woodruff key and spun on the crank or something.

Any input or things I could try would be very much appreciated.

Gaz

[devojunior]

sounds weird pal although you say your getting a strong spark i would try a new plug for the sake of a couple of quid and a 1 minute job,

when you try start it without any luck what colour is the plug and is it wet if its wet with fuel then try putting th eplug in the oven or heat up really well with a blow lamp ect cant think what elso to try,.

good look and let us know how you get on.

[Gazdaman]

Yeah, new plug is my next purchase just for the sake of ruling it out. I've never heard of a plug sparking outside of the cylinder, but not inside though.

And then cooking it was my next try after that.

When I take it out it's wet with fuel, so I know it's getting through.

I'll check the timing after that I guess, but the generator seems to be tight on the crank, so I'm not too hopeful it's that (although it would explain everything).

The old ritual, compression fuel and spark. This bastard has all 3 and still won't go.

Gaz

[G]

[Gazdaman]

Yeah, float was moving fine, and the float bowl was full of fuel that spilt all over my hand when I spun it round to clean it out.

I am starting to think electrical, either no spark, or timing wrong. That would fit.

Gaz

[mad4it028]

ha i had that happen on my old kx 250 the stator plate had come loose and turned simple fix if its the same
____________________
always looking to buy bikes crashed ,unfinished projects,none runners pm me
currently riding kawasaki z1000 only bike ive ever loved

[Gazdaman]

[mad4it028]

mine was just mega loose screw had fallen out i managed to refit and tighten with lock tight without removing the fly wheel
____________________
always looking to buy bikes crashed ,unfinished projects,none runners pm me
currently riding kawasaki z1000 only bike ive ever loved

[bikersupermot...]

[Gazdaman]

For those of you that guessed timing, give yourselves a pat on the back, the woodruff key had sheared allowing the generator to play havoc with itself.

Just need to get a new one and hope that's the only problem.

Gaz

[bikersupermot...]

great uv found the prob! ... btw im liking your list of owned bikes!
____________________
tinybikes

[Gazdaman]

[Gazdaman]

Fitted the new woodruff key today, popped the generator back on.

Kicked it over and it burst into life on the first kick.
Excellent!

The guy came and collected it within about 3 hours of me telling him it was fixed, a tad excited he was.

All's well that ends well.

Gaz