02 Txt 280 Ran Backwards, Now Won't Start

[climberevan]

Hi all, I'm new to the site, and to trials. I just bought an '02 TXT 280 (regular, not Pro). It appeared to be in good used condition, and well maintained (clean oil, clean filter, lubed pivots, etc). It started first kick whilst I was checking it out.

Fast forward 2 weeks, and a lot of driveway and several more adventurous rides. I rode it on some trails/rocks for about 2 hours, and it seemed to be running OK, but was kind of hard to get started after stops on that ride--it really required a firm kick.

The next day I pulled it out to ride again and it didn't want to start. I leaned the bars against the shed and started kicking away, and eventually it sputtered a bit and seemed to be running poorly, but running. The problem is that it was running IN REVERSE. I put it in gear and it took off backwards! I then shut it off, and kicked it like a mainac some more and it eventually started up and ran again, also IN REVERSE.

So I shut it off and tried to bump start it to force it to run forward, but it wouldn't start. I have been unable to start it since.

Things I've checked:

Entire fuel system removed, totally disassembled and cleaned (blown out too), then re-assembled with fresh 80:1 fuel

I removed the flywheel and checked to see if it had spun on the shaft--nope, and Woodruff key is in place. Stator is on its marks and looks fine.

I checked the rest of the ignition stuff as best I could, and replaced the spark plug. The coil resistance checks out, and the stator puts out about 35V AC while kicking it over.

It makes a spark, but it looks really weak. I compared it side-to-side (with the GG's plug) to my KTM 200, and it looks a lot stronger on the Katoom.

It appears this year has a type of CDI that takes only 2 wires from the stator and does not have a pulser coil at all--I guess it senses voltage spikes and sparks it based on that.

At this point I think it must be ignition as fuel is definitely being delivered. Ignition parts don't seem to be inexpensive for these, so just throwing parts at it is not an option.

Ideas?

Huge thanks in advance--I really want to play with my new toy.

Evan in NV

[lineaway]

Any two stroke can run backwards. Have you grabbed the flywheel a good shake to see if the mains are bad?

[dadof2]

If it does not have a pulser / trigger coil to time the ignition I think the CDI will sense when the voltage from the source coil changes polarity and use this as the ignition trigger.

All electronic ignitions can develop faults which change the timing and you need to check if this has happened. Mark your flywheel with a mark to show TDC then put a strobe light on to see where the spark is actually occurring. I would expect it to be between 4 and 23 degrees BTDC.

post what you find

Since the bike won't start you need to take the spark plug out - make sure it is still earthed, spin the engine with an electric drill. It difficult to get a strobe reading just by kicking it over.

Edited March 15, 2014 by dadof2

[climberevan]

Thanks for the quick reply. I hadn't thought to use a drill to turn it over... The flywheel feels very solid, btw.

I finally got the timing light to work, but I had to put in a jumper of bare wire from the plug wire to the plug and clamp the pickup around it.

I've tried to attach a photo. The longer mark on the case is TDC , as best as I could find it using a screwdriver through the plug hole. The smaller mark, well before TDC, is where the crank mark hits when sparking. Using a protractor I find it to be ~23 deg BTDC.

I can't seem to find the spec for it, but that seems like a lot... Should I adjust the stator in its slots to bring it closer to TDC?

Thanks!

Edited March 16, 2014 by climberevan

[copemech]

Get a flywheel puller and use it. inspect for sheared woodruff key. I would order both at the same time if I were you!

[nelly1]

id order a new flywheel nut too good luck

[wobblenorbed]

Had the same problem, turned put to be a sheared Woodruff key. Thirty pence later sorted. I now always carry a spare in the tool box.

[climberevan]

Thanks for the replies guys. In my first post I wrote: "I removed the flywheel and checked to see if it had spun on the shaft--nope, and the Woodruff key is in place. Stator is on its marks and looks fine."

So, any suggestions other than the already-ruled-out Woodruff key? Does anyone know what the proper timing should be? It seems lots of 2T are around 17 deg BTDC, but I can't find the spec for this one.

[thats_a_five]

Running backwards as you describe is 99% sure to be because of timing too far advanced. The timing is done with a dial indicator screwed into the spark plug hole and measuring its travel as you rotate from Top Dead Center. A screwdriver is not accurate enough to set the timing accurately but could get you close.

Here is some info about the GG ignitions. I did not record the source but I think it is reliable.

***

THE TIMING OF THE ENGINE IS AS FOLLOWS:1991/93 GT25 2.3mm BDTC

1991/93 GT32 2.0mm BDTC
1993/2001 GT16 0.7mm BDTC
1991 AIRE 250 2.7mm TO 3.0mm
1991 AIRE 327 2.4mm BDTC
1994/2001 (ALL) 2.7mm BDTC

ALTERNATIVE FOR SMOOTHNESS 1995/2001 338cc,327cc 2.4mm BDTC

ON BIKES MADE BEFORE APRIL 1994, (MOTOPLAT SYSTEM) SOME OF THE ENGINE ELECTRICAL PROBLEMS HAVE BEEN CAUSED BY POOR CONNECTIONS AND CRIMPING OF CONNECTORS. THE GROUND IS VERY IMPORTANT! THE MOTOPLAT IS A "NO CIRCUIT GROUND SYSTEM". THERE MUST BE A GOOD GROUND PATH BETWEEN THESE PARTS.(THE COIL AND STATOR GROUND BY THEIR MOUNT. THE BLACK BOX HAS A GROUND WIRE).THE BLACK BOX SHOULD BE GROUNDED DIRECTLY TO THE FRAME. THE MOUNTBOLT FOR THE SILVER VOLTAGE REGULATOR IS A GOOD GROUND PATH. THIS IS VERY IMPORTANT! SOME BIKES HAD THE BLACK BOX GROUNDED TO THE WATER OVERFLOW BOTTLE (1992/1993 MODELS). THIS CAUSED A PREMATURE FAILURE OF THE BLACK BOX. THE CHROME FRAME IS A GOOD GROUND BUT NOTE THAT THE ENGINE MOUNTAREAS MUST BE CLEAN UNPAINTED FOR THE STATOR GROUND TO PASS TO THE FRAME. SPARK PLUG CAPS THAT DO NOT FIT PROPERLY,OR ARE IMPROPERLY INSTALLED TO THE COIL WIRE. WATER IN THE IGNITION FROM IMPROPER SEALING OF THE MAG COVER. DEFECTIVE KILL BUTTON OR KILL BUTTON WIRE IS TOUCHING GROUND. (MANY TIMES THE KILL BUTTON IS THE CULPRIT! ALWAYS DISCONNECT THE KILL BUTTON AND TAPE OFF THE WIRE. TEST THE MOTORCYCLE FOR PROPER OPERATION BEFORE ADVANCING TO FURTHER ELECTRICAL DIAGNOSIS.)

TO TEST THE IGNITION STATOR OR IGNITION COIL WITH AN OHM METER (MOTOPLAT):
NIPPON DENSO COIL:

THE RED LEAD INSERTED IN THE SPARKPLUG CAP AND THE BLACK PROBE TOUCHING THE BODY OF THE COIL.RESULT:18K OHMS

THE RED LEAD TOUCHING THE MALE WIRE PLUG ON BODY OF COIL,THE BLACK WIRE TO GROUND ON THE BODY. RESULT:1.5 OHMS

MOTOPLAT STATOR:
UNPLUG THE BLACKBOX MODULE IN FRONT OF RADIATOR OVERFLOW BOTTLE.
GROUND THE BLACK PROBE ON YOUR OHMMETER.(CHROME FRAME IS GOOD GROUND)
HOLDING THE HARNESS PLUGIN FOR THE BLACKBOX:
INSERT THE RED PROBE INTO TERMINAL FOR THE BLACK WIRE.RESULT:35 OHMS
INSERT THE RED PROBE INTO TERMINAL WITH BLUE WIRE.RESULT:45 OHMS
INSERT THE RED PROBE INTO TERMINAL WITH YELLOW WIRE.RESULT:1 OHM

FOR DUCATI AND KOKUSAN SPECIFICATIONS, SEE THE OHM READINGS INCLUDED WITH THE WIRING DIAGRAMS AT: http://www.gasgas.com

SPARK KNOCK: THIS CAN RESULT FROM A NUMBER OF DIFFERENT CAUSES. LOW WATER LEVEL IN THE COOLING SYSTEM WILL CAUSE THE ENGINE TO RUN HOT AND DETONATION (SPARK KNOCK) WILL RESULT. THE COOLING FAN NOT OPERATING. FAILURE OF THE WATERPUMP. THE QUALITY AND AGE OF THE FUEL (MOST COMMON REASON). CARBON BUILD UP ON THE PISTON. CARBURETOR JETTING. DEBRIS BLOCKING THE FUEL JETS IN THE CARB. USING HIGHER GEARS AT LOW RPM. THE IGNITION TIMING OF THE STATOR. WORN PISTON PIN OR CONNECTING ROD BEARING HAS A SIMILAR SOUND.

TIMING NOTE: NO ONE HAS FOUND THEIR ORIGINAL FACTORY STATOR TIMING TO BE INCORRECT AS IT IS SET IN AN ALIGNMENT JIG DURING ENGINE ASSEMBLY.

[dan williams]

Should change your moniker to That's an Expert!

Bad mojo using an aluminum/steel or magnesium/steel contact as a main circuit ground. Beta did that with a lug on the triple clamps for a while and it was a really stupid idea. You might want to run a separate ground wire if possible just to be on the safe side. A high resistance ground with electronics, especially ones that deal with high current pulses, is just asking for trouble.

[dadof2]

I think your bike is 68mm stroke and will have a con rod length of about 130mm. With these dimensions 20 degrees advance equates to about 2.7mm BTDC, so if yours is firing at 23 degrees BTDC it is getting on for 3mm BTDC which is about or possibly just beyond the wise limit.

I agree that replacing the woodruff key would be a good move.

You say the engine is hard to turn. Could a main bearing cage be beginning to fail? If this is the case the crank will run stiff and out of true and affect the timing and possibly cause crank seal leak.

[climberevan]

Awesome, thanks for continuing to help, everyone!

I employed the dial indicator method of TDC location and determined that my original mark was a bit off. Using my more accurately determined mark I find the plug firing point to be more like 20 degrees BTDC. Turning the engine with a drill results in a good looking, blue spark every time. I also cleaned the grounds and made sure everything was tight.

I can't understand why I'd need to replace the woodruff key if it's perfectly fine, but I can do it just in case.

The engine is not at all hard to turn with the plug out. I can easily turn it with my hand on the flywheel. It's just that when the plug is in the compression is a bit more substantial than I'm used to on my KTM 200, I guess.

So, at this point it appears that the ignition is in fact doing what it's supposed to be doing, so I suspect the fuel delivery system.

The reeds look fine, and I took the carb off and cleaned it again, verifying that there was fuel in the float bowl.

What else could be preventing this thing from starting? I'm at a loss.

[thats_a_five]

Sometimes woodruff keys can shear or deform and the fault may not be easily visible. Its a cheap part to replace if you are unsure. If its hard to find one, I have made homemade ones out of a metal washer or even a coin.

I doubt it is a fuel problem. It really sounds like a spark timing issue. Remember, there is no mechanical advance mechanism, the advance is done by the black box. I suspect the box has failed and gone to maximum advance. I have seen offset woodruff keys that would have the effect of retarding the spark. It might be smart to get one and try it.

[b40rt]

Are you sure the reeds are ok ?

[climberevan]

I removed the reeds and they look fine, with a decent seal. Even if they aren't perfect, the bike should still run.

Whilst spinning the crank with my drill I noticed the timing does change. At lower RPMs it was less advanced, perhaps 10deg, then moved up to the 20deg mark and stayed there. The blue marks were on it when I acquired it, and as you can see it's on them. Should I just move the stator to retard it and see what happens?

Let's put the woodruff key question to bed: