Help needed with kdx200 running bad

[Gladiator]

Dude, This happened to me on my 1993 KDX250. I finally diagnosed it when my ignitor completly died. It was slowly going bad and the bike was giving me all kinds of problems. Always had spark so I am glad it fianly died and all of a sudden the ike had no spark. a new cdi and undoing some of the jetting I tried wa all it needed. Good Luck.

 

[canyncarvr]

Something is gettting missed in a big 280 kind'a way, here.

1. WOT on compression test.

You bet. The point is to determine how well the engine compresses the intake charge....NOT how much air you can squeek past a closed slide! Open it up!

2. (shoulda been #1) 280!!! main???

This has to be a mistake!!! Tell me it's a typo.

From CDave's site:

1989 to 1994 KDX200

Stock -Run the stock R1172N jet needle in the second from the top clip position, 48 pilot jet, 155 main jet and fine-tune the pilot circuit using the air screw.

Even WITH a typo (if it is a 180, not a 280)...your carb is way out in left field. The pilot is also so far out of whack...it's a wonder the thing runs at all!!!

BTW...on the 'running' part. You described the bike as 'not being able to get out of it's own way' (as I recall...didn't go back to page 1 to check). Is it 4-stroking when this is going on? Blubbering and smoking?

Plug color really doesn't have much to do with anything except when used with a WOT plug/chop test. Doesn't seem that's happening, yet.

I go back to when you leaned the needle (dropped it), and things improved. You've got to, absolutely must, please!! get the jetting sorted out!!

Yes, by all means keep at this problem. It's fixable. Don't despair over it, keep at it (as woodsy said) and you'll get it.

But DO read the suggestions. IF the 280 number is correct...this could have been resolved a long time ago!

Please repost with the numbers of the jets you have (no typos twice, please;) ). If your numbers are correct...get the jets CDave recommends. Change 'em. Let us know what the result is.

3. 20:1? Was that a joke? 32:1 is generous, plentiful. 40:1 is good to go unless you are SEVERELY screaming this bike (constant pinned throttle, sea level, big-time load.....like on the dunes maybe).

4. I'm sure there is a #4...but...what was it??? ;)

 

[briora]

Canyncarvr, wooodsy & all have have been helping me, I really appreciate all your help. It's great to have a resource like this and if we keep at it maybe, just maybe we can fix this thing.
As far as the jets go, remember this a 1984 bike and on the just kdx tech tips it lists the proper jets at 280 main & 35 pilot, it may sound strange but thats what its supposed to be. As far as 4 stroking it and blubbering and smoking, no. The revs just don't get up there, you give it more gas and the revs barely increase they stay real low, Again it will crank up a hill and have tremendous power you could even get the front off the ground when it's first running. Looses everything when it gets hot.The repair manual is ordered but won't be here for a while. I would like to test the ignition like woodsy recomends but not sure how to do, I do have a tester I could borrow to do it but again not sure how
Thanks
Bri

 

[briora]

also did wot compression came in at 130

 

[canyncarvr]

My humble apologies. Summore? A double barreled post due to edit...

 

[canyncarvr]

My humble apologies. Seems I'm the one not reading too goot.
No excuses. I even went back to the 1st page to check the year!!

Sheesh...

CONSIDER the source, 'eh?

Fredette says:

The carburetor jetting should be as follows: 1983, 150 Main jet; 1984-85, 35 pilot and 280 main jet.

If it's not 4-stroking when it's doing this 'running bad' stuff...howabout something completely different?

Are the brakes hot when this happens? Could they be sticking? Does the bike push in neutral ok when it's acting like this?

I thought THAT one up in the shower this morning. See!...even if my thinking is wrong (the year), at least I'm thinking!!!;)

I don't think the static resistance of the coil would tell you a whole lot. For a reference, maybe...the '00 exciter is listed as 250-370ohms...then they say that's with the meter set to X100. 2.5kohms? Sounds high to me. If you can't get the info from someone in the meantime, the manual will tell you where the connector is you can check that. You could take off the engine cover to see what color the wires are coming from the exciter. Follow those to a connector suitable for sticking some meter leads in.

Still..what if the brakes are sticking? I'd think you'd smell that....

This'll get fixed. Stick with it!

 

[briora]

It's funny you say that, I said to my son the first day he got it, you should check thode back brakes they are wicked hot! He doesn't have any back break right now. But we just talked about and were thinking after it dies on us. Itwon't start back up for a while, and if it were the brakes it would always start back up I would imagine? Clever thought anyway. I think testing ohms is out of the question for me until I get a manual, I'm not even sure what this bike has: cdi, coil, don't know so I won't pretend that I do. I wish I did know what it had, we have a good dirtbike salvage yard nearby and I could go get a few electronics and try it I do almost anything at this point. If I can't fix it soon it'll be heading the bone yard. I'd hate to trow the money away that I'd hate to throw the money away that I just paid for the bike but this is getting rediculas. Just frustrated I guess.

 

[canyncarvr]

No back brake now...cuz?????

Should never have been 'wicked hot' with the amount of riding you've done.

Is this a drum? Why no back brake, 'now'. It went away? Used to be ok? Put the thing on blocks, and the rear wheel spins freely?

Again...does it PUSH easy (in neutral) when it's running 'wicked bad'? ;)

An anecdote (to no particular end)..my riding buddy and I had just finished a bit of screaming downhill/tight stuff. He looked at his rear rotor, said, 'Look how BLUE my rotor is!' ...and then he touched it.

Ha! 'Wicked hot' indeed!!!!

The hard to start part could be unrelated. Can 'we' stick with just this one thing.

I wanna hear about these brakes........

Have a cold one. Relax. It will get resolved.

 

[briora]

Having a cold one right now. -uuummm good. The back brakes never really worked since we got the bike a couple of weeks ago. It does push easy when in neutral, and we had to push it alot! I asked the kid to check those brakes when first got the bike and I told him they were hot, Well I guess he rather play video games than fix his bike, since he knows dad will do it anyway. Lazy kid wait till he reads this!

 

[JasonWho]

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[canyncarvr]

If I'm more a hindrance than anything else...tell me to bugger off...

BUT..
Sorry, I still don't follow. If the rear brakes 'never really worked', how'd they get 'wicked hot'?

Jason:
Do you have exciter coil resistance specs for this bike (whatever year it is :()?? C'mon..don't hold back...just FIX this thing!!


And I'm still wondering about the 'white smoke' comment, too! IF it was leaking that much coolant, it wouldn't be a brown plug he'd be looking at.

Is it LOSING any coolant?

Cripes! I need a beer..........

 

[woodsy]

Bri: OK lets try this.. You cannot just take the stator cover off, follow the wires and check the color coded wire coming from the ignitor and expect to resolve anything.. Diagnostics simply do not work like that. You have to eliminate problems one at a time until the bike is fixed.
The specs/wiring diagrams that come in your manual will serve as a road map. Think about that. If you were to leave on a trip to the other side of the country and had NO idea where the other side of the country even was much less which corners to turn right or left on to get there, how far would you have to drive before you would be lost? That is exactly what is going on!!
When you get your manual it will say somethng like "ignitor coil tolerance 200 ohms + or - 50 ohms. Then it will show you by diagram or by explaination which terminal (place where wires hook together or into a device) to check for that reading and which 2 wires to attach your tester to - if you test the wrong to leads, you WILL get the wrong reading! This sequence has to be followed precisely or you will get erroneous readings and we all know that is not good!! Remember that if your road map is mis read you could end up in Jersey instead of California!!!
You simply follow the spec sheet and check stuff one item at a time and all will work out!!
The reason I said that you will have to check spec hot and cold is because you are having an intermittent problem. If there are folks out there who dont understand that HEAT has a way of changing perameters I am sorry - but it does!! Current flow (electrical) produces heat and some times it is just enough to cause the type of situation you are experiencing!! Dont get to upset with your bike - remember it is just a machine - IF MAN CAN BUILD IT AND MAN CAN BREAK IT, MAN CAN FIX IT!!!
I am sorry that your son had to expereince this with his bike but maybe both of you will learn some really positive things thru all this!! One of those things would be: when going to buy something like a used bike, take someone along who you trust will give you an HONEST opinion about it BEFORE you buy it - then listen to him!!!
At minimun come to a forum like this and ask lots of questins FIRST.. If things are not what they should be - walk away from the deal until you have it sorted out... I am personally on my way right now to look at a 91 KDX250. I have YEARS of riding and working on them experience but, if you look on the JUST KDX sight you will see that I asked for info about that perticular bike!!
I think it is a wonderful era this days!!! We can help each other from one side of the planet to the other!! That, my friend is what life is all about!!!
KEEP YOUR CHIN UP AND WE WILL FIX IT!!!!!
Woodsy

 

[JasonWho]

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[HUSKwKDX]

Quote by C-Carvr:
"And I'm still wondering about the 'white smoke' comment, too! IF it was leaking that much coolant, it wouldn't be a brown plug he'd be looking at.

Is it LOSING any coolant?"

I'm 'gonna take a shot in the dark here ... but would a '84 have any coolant or a radiator?

 

[briora]

Thanks guys,
No one here is a hindrance, I look foward to hearing from all of you as you can probably tell this thing is consuming me and causing to consume more beer. I am constantly checking this thread for your ideas. Canyn. I'll loof more into the brake thing, but at this point I think it's secdondary, but what the hell do I know. As far as coolant and the smoke, this bike has no radiator it is air cooled. When he takes off you can smell the fuel lingering in the air, this normal for a 2 stroke? Until my manual arrives should I try lowering the floats maybe? or putting the clip up one more notch to the top one ( I'm a little nervous to do any damage) We did check the bike well but unfortunately the problems comes after some time riding, we didn't get to test drive for the 5-10 minutes it takes to create the problem.
I will ship a case of those cold ones (if thats even legal) , to the one who finds my problem. HA you will need it!
Bri

 

[briora]

I am going to look at another kdx200 tonight a 1985, supposedly it is in mint shape, if so maybe i'll pick up that one and keep this for parts they are basicly twins. Just hate to shell out the 800. bucks if this one only has a loose wire or something.

 

[JasonWho]

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[briora]

well now I did it while fooling around trying to get it running right this weekend my kickstart won't return anymore! I guess the return spring is broken, I gotta bring it back manually. I've been doing alot of kicking lately. It wouldn't be related to my real problem would it? Return spring hard to replace?
Bri

 

[briora]

i

 

[pdq]

Briora:
Maybe your problem is not fuel or compression. I had a similar problem with my
85 kdx! It started and ran ok cold but after 5-10 min. It ran like S_it! I played
around with the carb forever,and was ready to roll the bike off a cliff..$^?*&^%&^!!!!
The problem I found was the CD ignition box was malfunctioning when it got hot.
It is mounted under the gas tank (and only 1" from the hot exhaust pipe"!! try swapping
this part. You could also try temporarlly duck taping it to a"cooler"side of the tank
to see if this helps.Allso I made up a heat shield to reflect some heat from this
component hoping this will prolong its life?
Hope this is of some help. Good luck.

 

[ACGUY]

Briora,
Sometimes a weak ignition stator can break down when the motor warms up. A cold stator would read good resistance, and if it changes significantly when the motor is hot, that may be your problem. I had a bad stator on a old XR250 once, and it ran great until it warmed up.

Also, regarding jets..... Sometimes folks like to run wires thru them to clean em, and they make the orifices larger than they should be. My point is that even if you read a number on a jet, it still may be enlarged or drilled out if you know what I mean.

If you have gone thru the carb like you said you did, then I would say look elsewhere like ignition, etc.....

Don't give up..... You will get it.

BOb

 

[briora]

Alright guys I'm down to the assumption it's the stator or the CDI. I took of the flywheel today and took out the stator and this is what I saw;
one of the 4 contacts where the magnet runs against was very well coated in a rusty film. The wires just before the stator have lost a little of there insulation, perhaps from the flywheel rubbing ( although when the flywheel was on the bike I noticed no play?) So my question is could this be the magical problem? Would it make my bike run bad ONLY after it was hot if the wires were bare? Should I try to tape them up or just buy a new stator. Trying to get this done without spending a fortune.

 

[canyncarvr]

What about trying to swap CDI units from the other bike? Like jason said? Buy THAT guy a rack of cold ones for his trouble.

IMO and all, but if it's a choice of one or the other, I'd vote for the box as opposed to the stator.

If you're going to try to insulate something already connected, use some RTV. If possible (it would have to be disconnected) use heat shrink. Electrical tape comes in a wide variety of types and qualities..most of it isn't worth diddle. 3M makes a tape (super 88) that's pretty good stuff. The one-each black vinyl tape from your local department store is likely useless.

And even with a good tape, its application is important. They make a cold shrink tape (for already connected stuff)...but it's pretty spendy.

 

[briora]

Didn't buy that other bike. I have nothing to switch it with. I am trying to fix the strator now, I'll let you know if it helps.
Bri

 

[canyncarvr]

Even if you didn't buy it, the guy might want to 'make a case of beer' by letting you use his sparkbox for 15 minutes. Probably go over there with your bike and plan to go on a ride real quick so he won't wonder where you are for a week...;)

Fixing up any questionable connections/wires is probably smart in any case..might as well do that first. THEN...(if you've priced a control unit), a case of beer is a good price to find out fer sure if that's it....or not.

Good luck! You're going to be happy when this is figgered, huh??