Vintage Dirt Bike Q & A

01 KX 85, no start
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Author:  Hammerlane [ Mon Jul 03, 2017 10:33 am ]
Post subject:  01 KX 85, no start

quick back story... young man brought an 01' KX 85 2 stroke basket case to me to rebuild, done. new top end and completed the rebuild.

My 1st mistake, I let the young man break it in after repeated conversations about RPM and breakin procedure.
well, long story short.. it just quit he said. 2 hrs on the bike.

Brought it home, he cooked the topend so I replaced it again no biggie. BUT.. no spark, took flywheel off and found the power coil wire had broken. due to $ an Electrospark stator was installed this is where the issue is I believe. Hours and hours have been spent trying to get this thing running and I am out of patience and tolerance. I am very mechanically but my understanding of the electricals on this are my weak point.

1. bike now has spark but still no start.

2. ohm's check on power coil is within spec, pickup coil is 50 ohm's under Kawasaki spec so I swapped out the electrospark with the original pickup that checks within spec. set gap at .015. I now have spark but the bike still will not start.

3. redneck check on the pickup voltage using a drill motor and a 3/8" socket adapter and was able to generate 1.03v max. spec says 4v. (again was a youtube redneck check so)

4. stator plate timing, I swapped the electrospark plate with the Kawasaki original so I had timing marks, I have run the entire range of timing and still no start.

can only generate spark if I kick it hard, no spark with low RPM kicks (is a red flag in my book)
how sensitive are these to timing, I believe the timing "window" would be very small in comparison to 4 stroke.
and I'm not exactly sure power output is optimum with the electrospark coil.

any help is appreciated.

Author:  Hammerlane [ Thu Dec 21, 2017 7:26 pm ]
Post subject:  Re: 01 KX 85, no start

Well, after extensive labor, scuffed knuckles, thrown tools and a slew of new language... ended up being the timing.
the aftermarket plate had no timing marks so I swapped the coils out with the OEM plate.
low and behold I ended up WAY off the timing marks and it fired and ran.. go figure.

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