88' 250r with no spark...not normal...

[JxxxOxxxE]

so I just picked up an 88' 250r from a friend that owns a local bike shop. a customer brought it in with a no spark issue, and they couldn't ever get anything out of it. It has a new cdi box (3 have actually been tried), new stator, and new coil. all components ohm out correctly and all grounds have been checked, as well as both kill switches bypassed...

so when we kick it over, we get nothing...here's where things get weird. if we wire a known good cdi box from a trx125 to it, it will fire...???

is it possible that the stator is not putting out enough voltage to fire the 250 box? since it fires with th 125 box, that shows that the wiring and coil is all ok to me...

what should I try here? I've got a good running 85 atc250r that I was thinking about switching the stator with just to se if that worked...???


any ideas???

[C-LEIGH RACING]

The stock TRX250R ignition 86 to 89, you will need to crank the engine over at least 750 rpm to get a spark & even then it will be a real little keen spark from the electrode. Outside in the sun you might not be able to see it.

I can go ahead & tell you this, the old TRX250R ignition will almost make you pull your hair out trying to sort them out.
Most time the biggest problem is the connectors in the system. The main connector problem is the one with the black wire with white stripe, that the main ignition wire.
Run an extra ground wire from the ground wire mount at the coil to the engine block.
Neil

[JxxxOxxxE]

Originally posted by C-LEIGH RACING
The stock TRX250R ignition 86 to 89, you will need to crank the engine over at least 750 rpm to get a spark & even then it will be a real little keen spark from the electrode. Outside in the sun you might not be able to see it.

I can go ahead & tell you this, the old TRX250R ignition will almost make you pull your hair out trying to sort them out.
Most time the biggest problem is the connectors in the system. The main connector problem is the one with the black wire with white stripe, that the main ignition wire.
Run an extra ground wire from the ground wire mount at the coil to the engine block.
Neil



first, thanks for the quick reply...


so, i'll try putting another ground on it...the funny thing is, when the 125 cdi is hooked up to it, it puts out an inch long arc at least...? I figured the 250 cdi shouldgive th same, but maybe not I guess...i'm going to mess with it some tonight...anyone else have any ideas...

[regg187]

Think about this first. the 125 box is for a 4-stroke. which fires every second crank revolution. I had a problem with my ign (earlier post 'intermittent spark') finally figured my flywheel was going bad -magnets- got a ricky stator lightend flywheel and I am as happy as can be. fires first or second kick all the time, and bonus the lighrt flywheel improved performance, definetly quicker.

Everything ohm'd out fine with mine too, but no way to check the magnets! good luck.

[JxxxOxxxE]

Originally posted by regg187
Think about this first. the 125 box is for a 4-stroke. which fires every second crank revolution. I had a problem with my ign (earlier post 'intermittent spark') finally figured my flywheel was going bad -magnets- got a ricky stator lightend flywheel and I am as happy as can be. fires first or second kick all the time, and bonus the lighrt flywheel improved performance, definetly quicker.

Everything ohm'd out fine with mine too, but no way to check the magnets! good luck.

thought of the flywheel already, and tried one off the running 85' ATC250r, and got nothing. I know the part numbers were different between the 2, but sure it should have fired it...


I have the 88' and the 85' sitting next to each other in the garage right now. I think I am going to start testing parts back and forth until I come up with something...

[JxxxOxxxE]

ok, a little update...this might get a little confusing...


I decided to do some swapping tonight. Keep in mind, everything on the ATC works fine....

So i put the ATC stator on the TRX, and got nothing, with either flywheel...I put the TRX stator on the ATC, and got intermittent spark. Basically i would kick it over, and get nothin until the motor stopped moving, then it would spark once. It worked this way with both flywheels also...With all the ATC stuff on the ATC, the spark is basically constant when kicked over...


I really dont know what to try next...I have a spare ATC harness that I think I am going to temporarily wire to the TRX to see if that changes anything..That will be tomorrow though...



Anymore ideas?

[wilkin250r]

I have had a problem with a short in the kill switch before. The switch itself would make intermittent contact and kill the spark. It was a small gap easy enough for the spark to jump, but it would still ohm out as an open circuit, so it was very difficult to diagnose.

Sometimes, problems can be difficult to find. I'm an electrical engineer, and even I have pulled my hair out trying to find ignition problems, and I'm supposed to be an expert at this kind of stuff.

It's not always as simple as "stator, coil, and cdi". You would be surprised at how many variables there truly are. You have connectors, kill switch, key switch, perhaps an aftermarket tether switch, ALL the connectors and wires, the coil ground wire, ect ect ect.

My first piece of advice is to start trying to eliminate some of these other variables. Bypass the kill switch and key switch, run a separate ground wire for the coil (as Neil stated earlier), and double-check the connectors to see if they are corroded or dirty. If you have tried a new stator, new coil, and new CDI, and these haven't fixed the problem, then the problem must be somewhere else.

[regg187]

Wilkin's advice is good stuff, he help me work with my problems.
I forgot to add I did run the extra ground off the coil wire, and I have no key, but I do have a dead man. If you can use a spark tester when testing , It is really easy to see if there is spark compared to the plug, and since there is no plug in the hole kicking speed is sure to make minimum required. Trigger coil? are you using the same one with each stator or just the one attached to each stator, certainly worth checking

[JxxxOxxxE]

alright guys, thanks for the continuing help. I will start going through the connectors tonight...I am pretty sure the shop that it was at had tried bypassing both kill switches, but I will make sure of that too...

The only thing that concerns me about the connections, is if there was a bad one, why in the world will the 125 CDI box make it fire?

I'll keep this updated...

[JxxxOxxxE]

well....I am at a loss on what to do...I tried running an extra ground from the coil, tried playing with the black/white connector and still nothing...

I plugged the TRX125 cdi box back in just to make sure everything was still fine that way, and sure enough, it was.....


i feel like there is something that I am just overlooking...but it just wont come to mind. I dont see how it could actually be this difficult...The thing throwing me for a loop is that the 125 box makes it fire...

[300excrazy98]

you make sure you coil to cap wires are tight and touching? They could come loose and you not even now it, and like you said just overlook it. Just an idea

Good Luck

[JxxxOxxxE]

cap and wires are all tight...the kill switches have been bypassed, and I tried the atc stator on the trx to no avail...everything ohms out correctly also...the plugs for the cdi boxes are different bewteen the atc and the trx, but I am going to do some splicing tonight to see if I can get anything between them..

[86 Quad R]

may be a lil late here but, you dont need to splice. as long as ya have a schematics and have the atc harness end. you can pull the wires from the atc end and place them in the atc end without cutting any wires.

[JxxxOxxxE]

ok, more update...Once I looked at it, I didnt end up splicing anything, just take all the plastic connectors off....


anyway, the trx cdi box gives spark on the atc, the atc box only give a spark on the trx after the motor stops turning, like i was saying earlier with the trx stator on the atc....i put the trx125 box on both of them, and it fires fine on either...

I have wiring diagrams, but it doesnt tell how the connections go into the trx250r cdi. Can someone look at their's and verify if this is correct....

With the box standing upright, my connections look like this...


l -blue/yellow l -black/yellow l -black/white
l -green/white l -green l -black/red

Does that match anyones? I know for the 125 box i have to switch the black/red with the black/white..I know it a slim chance, but i wonder if someone changed these before....


So what does the spark after the motor stops moving usually mean?

[wilkin250r]

I'm going to tell you something that doesn't make much sense. It's going to go against all that seems logical to you, and it's one of the few things I CAN'T explain well to get you to understand.

Forget the 125 cdi. Forget it completely, don't hook it up, and don't use it to test anything, and forget any information that you think it might be telling you about the rest of the circuit.

[brokenmike]

I know that this post is over a year old but was there ever a solution to this problem? I'am having the same problem i will kick it over, and get no spark until the motor stopped moving, then it would spark once.

Thanks

[86 Quad R]

thats usually a sign of a bad CDI unit

[brokenmike]

I swapped out a good CDI,same problem,swapped out 2 good coils,same poblem,swapped out a good flywheel,same problem. it has a brand new ricky stator, stator. good connections at all connectors

[86 Quad R]

this may be a steee-upid question but, have ya changed plugs?

[brokenmike]

I tried brand new plugs and ones that ran in other bikes too. I will figure it out and let you guys know

[Aceman]

I'd try a stock stator. If you've replaced all those components already, I'd be looking hard at that Ricky stator stator as the problem. Don't forget to look hard at your wiring and connections too. Pull all the electrical tape off, etc to make sure, even if it looks okay. Are all your wires tight in any crimp terminals you may have, no oxidation?

[brokenmike]

I found it...I had an old stock stator laying around,it was really really rusty.I wire bruhed it off and hooked it up and it started on second kick and idled. This just goes to show you that even brand new parts can be defective