86 Tecate won't start only exhaust backfires

[nd4speed]

So I tried 2 known well configured carbs on the same style 86 KX motors.

Last time I rode it, it would rev up on its own even though throttle was steady, then it would bog and die. It would start up immediately. I would ride for 3-5 minutes and repeat. Plug fouled once that day before this began.

Last time it ran, it started fairly easy and smoked real bad and bogged in the mid to upper rpms.

Now it doesn't start, just backfires out the exhaust.

First, don't think it is lean.
Second, there may be gas in the exhaust. I am pulling the pipe next.
Third, I pulled the flywheel cover and all looks well but I did not remove the bolt and look for a sheared key. Appears to be a Tecate OEM flywheel. Not rusty. But there was a line 2-3mm wide around the O.D. of the flywheel like something was lightly scraping it.

Has anyone experienced these symptoms when their stator coils went bad?

Any advice?

[nd4speed]

I realized I drained the oil and never refilled the trans case.

Maybe the clutch side crank seal is bad and now it is just sucking air instead of oil.

Does that sound like it would cause a lean condition?

[fabiodriven]

Some of the symptoms you've described sound similar to when my stator went.

[boosted96cobra]

Yep, when my stator went it did the same thing. I also still had spark at the plug, just a slow spark, and it also ohm tested the same as a good stator I put in it. It was still bad...

[JohnR.]

Give it a little shot of ether. If it starts then its probably NOT the stator. However, from the occasional pop you're getting it sounds like mine did when the stator went.

John

[MIK6]

Check the plug coming out of the stator and into the harness. Them wires are old too, and they tend to move around w/ vibration.
I have had my 87 act the same way, only to have to push the wires out of the plug, shorten them and crimp new ends on. Another time i had the wire to the coil go bad, same thing, shorten it, splice a longer wire w/ a new terminal end on it.
KISS method of repair and trouble shooting LOL.

MIK6 / Mike

[nd4speed]

Kick it over and after 6 kicks there is enough gas that ignites and exhaust backfire.

Put dielectric grease on wire ends- no help.
Put oil in trans but no fire.
No excess gas in pipe or crank case.
The reeds are wet with gas but no puddle. They look intact but hard to tell without cage off.
Pulled stator bolt and flywheel key looks intact.
Spark looks kinda weak. It sparks all over the tip. Hard to tell.
Sprayed contact cleaner in there (didn't have ether) didn't fire.

Guess I'll try the spare KX250 ignition since it works.
After that comes the KX500.

[Erics350x]

check the woodruff key for the flywheel.
the high reving sounds like you have a air leak or clogged fuel system

[nd4speed]

Flywheel key is fine and the stator looks clean as could be. One of the magnets was off after I tapped it with a rubber mallet to loosen it up.
Oh well it was time for the ticking Tecate magnet bomb to go in the trash any way.

Fuel system is not clogged. Air leak is still possible.

So I have yet to strip the KX. I got side tracked getting parts and my motorcycle tire changed.

[nd4speed]

Put all the KX electrical on there and it started on the first kick.

Kinda late and no gas tank on it so I just shut it off.

Put my ugly DG pipe back on it.

Don't know if the crank seal is bad yet.

Have to make a grab bar for it and finish it up tomorrow.

[nd4speed]

So I put ATF in the trans.
Gas just began pouring out off the bowl overflow. I need to tune this carb.
It starts and runs without bogging but it still smokes a lot.
The smoke is white and corresponds with ATF.

Here is some pics and video what do you think?
Bad crank seal?
Too rich?

http://www.youtube.com/watch?v=V2CNRUCAzrY

Turns out the float needle valve was bad. Changed it with an old one that seems to work. Still seems to smoke at idle.
It is a Mikuni VM 38mm with a 370 main at about 70 degrees 1500 ft elevation.
The plug is oily,wet, black but only on one side of the porcelain.

Going to try a 330 main next cause that's all I have. I could not find any info about where to begin with a main. I was running 280/290.
Guess I'll keep dropping mains and if it keeps smoking then the crank seal is bad.

[nd4speed]

I dropped the main to 330 and it stills smokes and seems to lose some power at WOT.
The thing revs a bit faster now and WOT seems like too much.

I know I need to ride it and get it hot, but I live in a city a block from a cop shop.

People say the smoke should smell like crap but I can't much tell the difference. Maybe my sense of smell sucks from all the gas I huffed messin with the carb.

I made a grab bar for it but I'm kinda frustrated and think I'll come back to it later.

Grab bar is off a 1987-1990 LT250R Suzuki. Lines up on the right with one hole to drill. Have to make like 1/2" spacers on the left with one hole to drill. You have to cut off an exhaust hanger post but that can be cut into the spacers you need.

[nd4speed]

Well I went all the way down to a 250 main which should be super lean and it still smoked a lot.

I drained the oil and went back to a 330 main and it seemed to clear up some and rev out all the way. Still smoked but not as bad. Could take awhile to clear out.

Guess I am going to build a leak down tester.

I suppose the reeds could be bad but I'm guessing the crank seal is shot.