2001 EC 250 plug issues HELP

[Silver]

I have a ec 250 that is fouling plugs.Also when reved up is cutting out sounds just like a rev limiter is kicking in.The bike has the LTR jet kit in it I've jetted it down to a 175 main ,40 pilot and moved clip up to the last notch on the needle also have #7 slide.I don't get much spooge out of the pipe now I did when it had 178,48 and needle was up one position.The cutting sounds electrical to me it just started out of the blue.I've checked all the wring have not found any thing bad yet .The cutting out deal is there whether bike is hot or cold makes no difference.I strted bike to night it ran for 10 seconds and plug fouled.Put in a new one and rode 10 miles of tight single track and fouled that one (br8es).Not real sure where to look or what to try I check power valve,carb and wiring from cdi and coil all seemed okay.I have an enduro this Sunday so need help ASAP.Thanks Mike

[JoshP]

I had a problem like this and it was out of the blue as well. Went riding one day, headed down the road barely touchig the throttle, got about 20 yards into the woods and the bike just died when I put a little load on her! Basically it would start it, warm up, I could run it but once I put load on it it was like someone was pressing my kill switch. I tried everything (Even replaced all the wires) and in the end it was my CDI box. Not a cheap fix either, I was lucky to be able to burrow one from a friend prior to just buying and trying. I believe the CDI's are the same from until 03 they changed to a different style CDI. I'm not sure if that is your issue but sounds pretty close to it. If you can burrow a box from someone or talk to a shop it's worth a shot. I was about ready to use the old push of cliff method prior to checking that but when they go they just go and either need to be re-programmed or replaced.

[Silver]

It seems to run fine just won't rev out.It cuts out on top just like a rev limiter would.I bought a spark tester today and I can make the spark jump 7/8 of an inch.Seems like very good spark to me.So I don't think weak spark is the issue.I'm also at wits end .I don't know any one to borrow a cdi from so that is out.I checked power valve again tonight and that is working fine.Any one else have any idea's.Mike

[MattR]

Hi Mike,

The LTR jet kit worked very well in that bike, in the long run I would recommend setting it back to that. It was slightly rich at low speed but was great everywhere else.

Now to your current dilema... fouling plugs that quick is very strange. Actually, I never fouled a plug in that bike which really surprises me. So let's start with the basics before moving to the electrical things. It sounds like it is getting too much fuel relative to air. If it was the other way around, then I would say you have an air leak in the reed valve manifold or airbox boot. However this is not your case.

For too much fuel, my first recommendation would be to pull the reed valve and check the reeds condition and if they seat properly. Hold the reed valve assembly up to some light. If you see any light between the reeds and valve body, then those reeds need to be replaced. In a pinch, you can flip them over to see if they can fully seat. You should also disassemble and hold each reed up to some light. If you see any fine pin holes of light between the fiber-weave then those reeds are bad.

When you have the carb off the bike, you should also verify the float height level and the floats themselves. Shake the floats to make sure no fuel is entrapped and making them heavier than stock. If the float height is wrong, you will also be getting more fuel than normal.

Let me know what you find out on these two items.

[Silver]

The reeds are new boyseen pro series replaced after first round of fouling plugs.I pulled them out last night and did happen to see several pin holes in one and thought that seemed odd.Where should the float height be set at and how do you tell.I looked through the book and found nothing pretaining to setting float height.I did check floats for any gas in them and they are fine in that regard.Love the bike other then this current issue.Thanks Mike

[MattR]

I don't recall the float height level and will try to look through the workshop and owners manuals. Until then, here is a recent post about the float height.
http://www.gasgasrider.org/forum/showthread.php?t=1333

I had another thought about the over-rich condition. Have you noticed any recent leakage contaminating the tranny oil (milky color) or low coolant level? For example, a water pump seal could seep internally and mess up the fuel/oil ratio.

Looking back at your first post, I noticed you said it is also cutting out at high revs. Is this a bogging-type cut out (rich) or lack of fuel (lean)?

GMP, do you have any recommendations on this?

[GMP]

Silver,

Ok, first go back to the jetting that worked when you got the bike. Jetting will not change overnight and cause a problem. We will assume a clean carb with proper float height and clear vent lines. Starter plunger operates smooth and returns properly? Good, fresh pre mix with a good oil. Clean filter. No rag in the airbox right? Sounds like a stupid question but it has happend. Good reeds and no leaks.

Verify the PV is operating properly by running the bike with the right side PV cover off. The plate should hit the stop bolt at high revs.

Pipe/silencer/spark arrestor clear?

Does the bike blow a LOT of white/blue smoke before it fouls? If so, suspect a primary side crank seal.

Now electrics. Remove the kill button and try it. Remove, clean, and dielectric grease EVERY connection including frame grounds. Inspect the coil. The HV wire threads onto a threaded stud in the coil body, like the cap. This can come loose and moisture gets in, causing additional resistance. This happened to my '03. Unthread the wire, cut it back a few mm, and reinstall it with some sealer to the coil body. Do the same with the cap. Fresh plug.

Go through all of this and let us know. If its still a problem suspect the coil or CDI.

[Silver]

Carb is clean,vent lines are all open.Just changed tranny oil last night no contamination.PV is working fine pulled cover watched it do its thing.Pipe ,silencer all clean and clear.I raced an 85 mile enduro with the jetting I have in there now 175,40 and it ran great no plug issue nothing.Came home bike sat in garage for a few days problem was there when I started it up.I did have a pretty hard crash but raced an other 25 miles after wreck and bike ran great.It seems to have came straight out of the blue.I checked all the wires and conectors from cdi,coil,head light everything looks fine.Spark just kicking it over is very bright and blue and jumps 7/8 on spark tester.Going to hook up a timming light to test my juice while it is revved up.Bike does blow some blue/white smoke.I never noticed a lot of smoke when it fouls.Mike

[GMP]

Just because the spark is good visually or on a tester at kick speed doesn't mean its good at high RPM and/or under compression. Try a non-resistor B8ES plug, any better? If so your on the right track.

Did you consume any transmission oil? Does the exhaust smell typical of two stroke oil or have a different burned oil smell to it? If so the seal is easy to change, no case splitting.

Take a close look at the starter circuit on the carb. Last ride with Cruiser a rock kicked up and bent the rod on his bike, not allowing the plunger to return all the way. Freak incident. Symptoms were exactly as you describe.

If you addressed everything mentioned and all checks out, try to swap a coil or CDI. Maybe the coil took a hit in the crash. Again, the HV wire.

[widebear]

Silver. Did you pull the fuel tank and drain out the old pre mix and dry out the tank? Sometimes a little bit of water in the fuel tank or accumulations of condensation in the fuel filter' s can have you pulling your hair out. Also it would'nt hurt to check the cdi grounding. the best place to ground is right at the coil using a big fat ring conector. good luck.