Urgent help needed PLEASE

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#1
I COME TO THE PRO'S FOR HELP PLEASE, AS I SEE EVRYONE ON THIS SITE KNOWING MORE THAN I DO.

After this weekends ride my throttle cable snapped, And I got a new one,fitted the new throttle cable , now the bike won't start.
We were riding in wet conditions, if this is any help to you. After it started doing that I decided to do the top end again, evn though i done it three weeks ago.

The bike starts after a very long jog down the road, and wil idle very high for a period of time and then simply cut out. The engin is not smooth at all, and she kickstarted likea dream before the ride.
Oh yes I have also put a new plug in because i the bike was back firing. One of my friends mentioned that it could be the timing on the magneto that might of moved, could this cause my problem?.

And if this is the problem could someone please tell me how to set this.

Thank you for your time.
 

canyncarvr

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#2
re: . After it started doing that I decided to do the top end again, evn though i done it three weeks ago.

After it started doing...what?

re: The bike starts after a very long jog down the road, and wil idle very high for a period of time and then simply cut out.

Check the position of the white nylon cable retainer on your slide (fits into the needle retainer). It's easy to miss putting the tab of the nylon piece INTO the slot of the needle retainer. This would cause hard starting, rough running and high idle.

re: One of my friends mentioned that it could be the timing on the magneto that might of moved, could this cause my problem?.

And if this is the problem could someone please tell me how to set this

The timing on the KDX is set by: Removing the flywheel, then adjusting (loosening the screw and moving within the slots) the ring underneath. NOTE: from eric gorr..he said he's seen a LOT of damage to 2-stroke engines caused by riders ADVANCING their timing. Generally speaking...DON'T do that. Retarding on the other hand is (generally speaking) more likely to be of benefit. That is NOT a statement meant to specifically apply to KDXs.
 
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#3
Besides the nylon retainer being not seated (and yes I've done that and it ran like crap) it could be the new cable is adjusted to the point it is holding the slide up even when the throttle is closed. Thus the engine is being started with the power circuit not the idle circuit, which will flood the mortor. Done this one also. Remember what you changed between it running perfect and not. This is the only thing that can take you to the source of the problem, I.E. something you changed.
Good luck
 
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#4
Well, Thank you to Old Murphys LAW I missed the harescramble this weekend, And WOW was this an excellent race. I decided to take the bike to a local shop on Saturday morning out of pure desperation, and they said my Pickup Coil is the one causing the problem. Can you tell me which one is the pickup coil as I see two, And can i get this coil rewound. Oh yes what would cause this coil to burn out.
 

canyncarvr

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#5
Maybe it IS your coil. I'd like to know the outcome of replacing/rewinding it. It's a good one for being diagnosed as a problem when it's not.

Anyway..it's the one on the 'bottom'...looks to be covered with an epoxy wrap? As opposed to the lighting coil (on 'top') on which you can see the wire wraps.

Good luck. I think I'd be getting another coil before I had someone rewind it. I'd want to be pretty darn sure they knew what they were doing!
 
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#6
I have seen alot of stator coils go out of the older KDX's and alot of the times it won't run at low speeds but will at high revs. I had an 84' KDX250 that would only run when it was pulled behind a pickup ( SCARY) when the rpms were up , it would run and down low it would fall flat. The pickup coils were bad in it. But it sounds like you a have a different story here. I would find a coil that could be tried on your bike before you go to the expense of rewinding. If you have to rewind, Ricky Stator does a good job. First find a friend with a bike coil that can be tried and see if that is your problem.
Raz

BTW What year of a KDX are we talking about ?
 

canyncarvr

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#7
Raz:
You're right. I wasn't considering age as a factor. Just the idea I've heard more than once that, if it misses and you've changed the plug and it still misses...it MUST be the coil.

A 'coil' being nothing but a roll of wire, there isn't a whole lot that can go bad with it. Much more likely to be a connection, a plug cap..maybe a rubbed thru wire (if it's a coil-system reLATED problem).

Looking at it from the standpoint of, 'it worked before it quit'...(loose said it ran fine before the cable break), it seems downright odd that all of a sudden (sha-ZAM!) the exciter is bad.

Oh..my ID comment refers to newer kdxs. Earlier models may well be different.
 
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#8
Actually Canyrcvr that’s quite often the case with an engine coil. They overheat & break down the insulation. Once damaged they often are ok when cool so the bike starts ok & goes either short or hi resistance when hot.

If the system has a high & lo speed coil (can’t remember in the kdx) you may not notice that the lo speed coil drops out of action. Until you stop. Then it won’t want to start, more damage may have occurred so the coil it gets crappier still when cold. This is as RazBarlow has experienced. Some coils are a tad underated & some are just old like the clunkers some of us have ridden most of our lives.

When I first read the thread I assumed it may have been the woodruff key had broken & the flywheel rotated. That's always real funny. Especially the bit where you try to make a new one from a small rock & had to stop every 10 paces to redo it. I carry a spare now.
 

canyncarvr

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#9
I'm sure coil failure happens..just not as often as it's diagnosed as having happened.

re: woodruff key

Yeah..I've spent some time with a fingernail file working on a 'generic' key that didn't quite fit. Bikes generally don't work too well without one, 'eh?

The key to knowing it's gone (I found out) is the strange feeling from the kickstart lever. That flywheel sure makes a difference in the feel of the kick!

I still want to hear from loose if that (replacing the coil) fixed his problem!?

Hope so.
 
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#10
Yeah if the flywheel gets loose enough it does feel weird. Some bikes are more prone to ignition coil failure if the spec was a bit shakey & so do fail repetitively, & sometimes rewinds don’t emulate factory ones so fail quickly. A good coil rewinder will sort it though.

Just thinking whilst I was out for lunch. (a chicken salad & it was very nice thanx) & thought ‘’pick up coil’ was what the mechanic said. Now there is a lot of confusion as to what a pick up coil is. Not least between mechanics.

My speel is about the ignition coils that provide for the charging of the ignition. Not necessarily the timing of the ignition. Many have a separate coil for switching the SCR in the ignition & this may be what he refers. Some just use the change in phase between 2 coils. Again can’t remember the kdx one specifically.
 
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#11
SORRY I HAVEN'T BEEN AROUND TO CHAT SEEING THAT WE LIVE IN DIFFERENT TIME ZONES

THE GUY AT THE SHOP ALSO TOLD ME THAT THE ONE AT THE TOP (THE ONE WITH THE THICKER WIRE) IS MEANT FOR LIGHTS. AND THE BOTTOM ONE FOR SPARK, THIS IS THE ONE I AM GETTING THE REWINDING DONE ON. EXACTLY HAPPENED ON MY BIKE THAN WHAT HAPPENED TO RAZ,

I'VE LATELY BEEN DOING MORE JOGGING DOWN THE ROAD WITH THE BIKE TO START IT , THAN ANY RIDING. I WILL LET EVERYONE KNOW WHAT THE OUTCOME OF THE WORK IS.