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Doing well!

Nice to see you getting there!

The CDI (black box) is specific to each model. It regulates when the spark happens and has a curve programmed in to it. If you fit a CDI from another model (or same model but after an KTM upgrade) the spark will be at the wrong time and can cause damage. ((( Sadly the info on the sticker has a tendency to disappear so you will have no idea what bike it belongs to. This is the text on the front side, there is another one on the backside of better quality, but that one will tell you it is a 250sxf... as they use the same box for them all and reprogramme them at the KTM assembly plant where they fit the new crappy label. SORRY, SHOULD HAVE LOOKED AT YOUR PICTURE, THIS DOES NOT RELATE TO YOUR CDI BUT TO THE NEWER FLAT CDI BOX ))) On your one you can still adjust the timing manually also by turning the plate the pick-up coil is fitted to. There will be one line on the casing and two on the plate. Stay inside the two on the plate and test where you get the best result.

I wrote a lenghty piece on KTM CDI's a year ago that you find in "General" and go to "Bike tips And Tricks" and click on "Axzon saved quotes" and it is in there.

Do a google and you will find the KTM wiring diagram you are after.

I had no idea you were planning to put the bike on the road! You will be the king of holeshots from traffic lights! :laugh2:
 

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Discussion Starter #122
I couldn't find any wiring diagrams, but all the wire connectors matched up with male/female connectors. I taped and labeled most ends when i took it all apart but missed some. Everything is hooked up though and with the battery connected the trail tech system comes on and there's hardly enough power for the horn to sound, but it gives a little cough when I hit the button. I'm sure the system will charge up a bit when I do the break in procedure.

As far as road use goes, I'm a little hesitant. I've heard that it's excessively hard on the motor to be run on streets, even if throttle is varied. but the previous owner bought the bike as an sx and bought the wiring harness and lights to register it as an exc, which is what i had it registered as until it ran out. if i were to run it on the street consistently, i would like to get 17'' wheels, street tires, and upgraded brakes. that's easily $2k in parts so won't be happening any time soon. let me know your thoughts on stressing it.
 

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Roadworthy 2 smoker?

well she’s shaping up well now my friend. Good on you for your good efforts and persistance. We all make those wiring mistakes and complicate our reassembly process out of haste with our disassembly. I used to use small bits of masking tape and write wire identification information with permanent marker on the tape. Then the marking pen ink would dissolve when parts got washed and sprayed with contact cleaner. Best to try to take pictures and draw a wiring diagram as you did for previous post. I use plastic electricians wiring identification tape with numbers and letters to help with wiring and plumbing, but I still manage a mess now and again. I never understood the silly superstition some folks have regarding 2 smokers for street use. Two strokes get along fine on street as they have for over a hundred years. I suspect somewhere a few poorly jetted 2 strokes burned up or some worn out 2 strokes were blamed on their road going usage. I rode high strung twin cylinder air cooled street bikes and revved the nuts out of them without any abnormal failures with castor oil/fuel mix. Our old air cooled dirt bikes ran max rpm up and down dirt roads for 3 and 4 hours almost every day after school for years after we handed them off or sold them. I would not hesitate to run a 2 stroke on the road today. Perhaps some owners feel sorry for their bike because it’s revving 7 or 8 thousand rpm for awhile, but they are built sturdy for exactly that purpose. Most modern smokers are race derived engines and liquid cooled and plenty robust for street use. Modern 2 stroke lubricants are designed to stick to hot engine parts and protect them. Not to worry too much about hurting your smoker on the street if she’s jetted right. Maybe feel bad for your riding buddies when you spank them with your blistering acceleration and leave em in a cloud of sweet smelling premix and race gas:grin2:
 

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Discussion Starter #124
well she's all back together with a brand new Lectron carb but even after kicking until my leg nearly fell off, no start. I pulled the plug and im getting spark. I could smell the gas on the plug and I don't have a pressure gauge for the cylinder but I can feel the pressure out the exhaust can when I kick. not quite precision though
 

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well she's all back together with a brand new Lectron carb but even after kicking until my leg nearly fell off, no start. I pulled the plug and im getting spark. I could smell the gas on the plug and I don't have a pressure gauge for the cylinder but I can feel the pressure out the exhaust can when I kick. not quite precision though
Glad to hear that you have it all back together!
One suggestion on starting sequence, I do have to locate TDC with my kicker on both of my KTM 300's before they will fire.
I always did this on my four strokes anyway.
My XRL will not start regardless unless it is at TDC.
Might want to give it a try if you haven't already.


Rangerman
 

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Put piston in TDC, check how the magneto lines up. You might have the spark too early or too late. If I am not sure all is well I spray "Start Ya Bastard" in to the cylinder while spark plug is out. Then plug back, connect up and kick. If there is something wrong with the carbi/fuel it does not matter as the motor will do it's starting thing for a couple of revolutions. This tells you that all is not fully OK, but you are close!

Last time I had same issue as you now I found that my head gasket (the O-ring closest to the piston betweeh the head and cylinder) was not doing a good job. It is very easy to get that gasket wrong and you only need it to be just a little wrong and the bike won't start. So if all seems OK (timing, fuel, plug, air/fuel mix, compression even...) then I would have a look at that O ring. If there is even a small mark on it you need a new one! We replace ours every time the head is off.
 

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I would agree with @Axzon on possible compression loss as a possibility but I would also be interested in checking and making sure ignition module is wired correctly. I have seen instances of module wiring connections installed wrong and lighting coil will cause spark to trigger at wrong timing. You would observe a spark when cranking, but engine would not fire. You may want to verify wiring is correct to module.
 

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Discussion Starter #128
the marks on the case and magneto line up exactly how the manual states they should, but I'm not 100% sure the wiring is correct. the brake light works and the horn will just barely sound because of the pretty much dead battery. the issue is that this bike was just an SX which was adapted to be an EXC, so the wiring diagrams don't match what I've got on my bike. I might just have to bite the bullet, swallow my pride, and take it to a shop to get sorted out.
 

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the marks on the case and magneto line up exactly how the manual states they should, but I'm not 100% sure the wiring is correct. the brake light works and the horn will just barely sound because of the pretty much dead battery. the issue is that this bike was just an SX which was adapted to be an EXC, so the wiring diagrams don't match what I've got on my bike. I might just have to bite the bullet, swallow my pride, and take it to a shop to get sorted out.
We all get stumped and need help sometimes. No shame in asking for help if you need it. We are all in various state of learning. One idea I used to do with my hard starting race motors back in the day was to roll the bike down a steep hillside nearby. We used to call it “Honda Hill” . If that steep paved road wouldn’t start your bike, nothing would start it. Probably rolled 20 or 30 mph down that hill. Boys at my shop teased me about it and named it Honda Hill to piss me off.
Ha! Piss on them bastards!! That hill saved me a bunch of kicking...
 

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Discussion Starter #130
Lol if it works it works. I don’t have any hills near the storage unit I keep the bike in but I have a very steep one in my apartment complex. Might have to risk a noise complaint and haul her out here
 

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Lol if it works it works. I don’t have any hills near the storage unit I keep the bike in but I have a very steep one in my apartment complex. Might have to risk a noise complaint and haul her out here
okay. if it makes noise thats a good thing. if it dont make noise its a problem. if she does make noise and any particular person (without a badge) dislikes your bikes beautiful noises, you just show em what your middle finger is for and drop whatever is in your other hand and show em that middle finger also. they work better in pairs...😁
 

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Did you check/replace the head gasket?? Easy job: Header pipe off, drain water, head off. Fit new gasket, torque to proper setting. I assume you have tried a new plug or two??
 

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Discussion Starter #133
My only reservation on checking the head gasket is that I don’t have any extras lying around to replace it. Kind of a catch 22. If that is the issue I need a new one.... if it’s not the issue I might be ruining a good one by taking the head off and refitting. I’ll check it next time I get a chance though and gap a new plug as well. Why does the header pipe need to come off to check the head gasket? Do you mean the cylinder gasket? Thought the head gasket was the rubber O-ring between the piston and the head.
 

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Discussion Starter #134
Could the battery have an affect on it? I know the spark is generated by the magneto/stator but that’s also what give the rest of the bike it’s power right? So if half the power or however much is redirected to charge the battery and run the accessories, most of which are off (headlight etc), could that weaken the spark enough to make it ineffective?
Just a thought. I could take the battery to be charged up at a local auto parts store if that will help. I’m pretty sure it’s dead or at least very low as it’s been out of the bike for about a year.
 

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Could the battery have an affect on it? I know the spark is generated by the magneto/stator but that’s also what give the rest of the bike it’s power right? So if half the power or however much is redirected to charge the battery and run the accessories, most of which are off (headlight etc), could that weaken the spark enough to make it ineffective?
Just a thought. I could take the battery to be charged up at a local auto parts store if that will help. I’m pretty sure it’s dead or at least very low as it’s been out of the bike for about a year.
Your charging coil(alternator)should be independent of ignition circuit unless something is connected wrong or mixed up. This was my concern for your possible wiring mixup. When it's wired correctly your lighting coil, alternator and ignition are separate. It should start with dead battery or no battery at all.
 

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Re header pipe: Space. The pipe tends to be in the way so I remove it when I do the job. But I suppose you can leave it there if you want.

Re battery: Yep, that could be the issue. I am not familiar with the XC bikes, but I know that the 2 stroke KTM's have 3 stator setups:
1. The SX one that has no battery or lights and stator only feeds CDI and spark.
2. The XC ones w/o starter motor and battery. This is a stronger stator than the SX one and it is also able to provide current for the lights.
3. The XC one for starter, battery and lights. This one has the most "umph" and is a must if you have a battery and starter.

Why not connect your car battery to the bike with jumper leads and se if it will start?
 

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Discussion Starter #137
I have jumped my old street bike with my truck before but that was an in-line 4 cylinder with a starter. What would happen if it’s too much voltage or current for the system in my bike?
 

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Discussion Starter #138
Also I dint have a place for the battery to sit. Right now it’s suspended securely in the airbox by a spiderweb of zip ties. I would like to make it get a battery box to hold it in place somewhere but the airbox is a bit cramped
 

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Also I dint have a place for the battery to sit. Right now it’s suspended securely in the airbox by a spiderweb of zip ties. I would like to make it get a battery box to hold it in place somewhere but the airbox is a bit cramped
Probably best to leave jumpers on with donor vehicle engine shut OFF to prevent vehicle alternator from creating more troubles.:oops:
 

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Discussion Starter #140
Missed your post auggie

if it is independent then I’m stumped. I am getting spark and the timing marks are lined up. I’ll check to make sure that the piston is at TDC when the marks line up next time I'm with the bike. After that I guess the head is coming off to inspect the gasket.
I’ll still check the battery and have it charged/tested and if it still won’t start then I’ll try the sketchy bump start. After all that it’ll be going to a mechanic. The manual gives a not so in depth testing guide for the ignition system so if I can figure out how to test the coil and CDI I will. There’s a site I found that sells modern ignition systems for way cheaper than stock or aftermarket so we’ll see if it gets that far.
 
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