87 250x intermittent spark

[ruffram]

Thing makes spark about 1/3 to 1/2 the time u kick it through. and it seems to be completely random no pattern or consistency at all. Everyone told me it was CDI box. Got one from a running motor and it does exactly the same thing. All components check out fine with the Ohm meter per Honda service manual. Which I checked before the CDI so I was 99% sure it was the CDI but it wasn't. What am I missing? Stator? Any ideas? getting frustrated with this thing

[bwamos]

Clean the connectors on the wiring harness. Most likley have oxidized connections between the stator and the CDI.

[ruffram]

I have noticed that some of the insulation on the wires from the stator is cracked and some wire is exposed. If that wire is dirty and corroded would that cause the intermitent spark? I have check and cleaned the coneections with contatct cleaner before and same result. If so, should I splice in new sections of wire to replace the brittle and cracked wire?

[bwamos]

Certianally couldnt hurt.

My 300ex is a 1998 and I've replaced most of the wiring and connectors on it.

[ruffram]

I will give it a shot and see what happens is there any component like stator etc. that would cause this outside of corroded wiring?

[bwamos]

Sure a faulty ground on the Stator, or a CDI getting intermitent could cause this.. but I like to work my way from cheap fixes up. ;) Wiring, is cheap and if it's brittle/cracked it needs replaced anyway.

But, either of those is a lot more rare of an occurance compared to old wiring issues. Your quad is almost 20 years old, and has probably seen a lot of water, mud, etc... and most likely still has the stock wiring harness on it.

[ruffram]

That makes sesne, I was hopign for an easy fix which is why i bought the CDI box after Ohm testing all circuits thought that had to be it. I will try replacing the wiring from stator to connectors and see if that helps.

[ruffram]

So... Today I replaced the questionable wiring from the case to the stock harness. kick it over a few times and I still have a decent spark half the time and no spark the other half. I decided the problem lies within the stator and pulled the side cover off. There was lots of oil in there, and oil was on the flywheel and the stator. Is that right? Should there have been that much oil everywhere? Also, on the stator there are 8 little "coils" i'll call them. 6 of them were nice and copper wires were plainly visible yet lightly covered with oil. @ of them seemed to be coated with some dark rubber looking gunk kindof like melted insulation. Is that how it should look? I haven't seen too many stators so I dont' really know thanks for the help

[wilkin250r]

Sounds like a normal stator to me. I can't tell you for certain, but based on your description, it sounds perfectly normal.

Your stator has different parts to it. The "nice" coils you see are the lighting coils. Just like the name implies, they produce electricity for your lights. Those coils combine to produce somewhere between 15 and 50 volts, depending on how fast your engine is going. It gets regulated down to 15 volts once it gets out of the stator.

The two coils covered with gunk are the exciter coils. They produce about 500 volts, which gets stored in the CDI. When your CDI gets the signal from the pulse generator, it sends this 500 volts through the coil, where it gets bumped to several thousand volts. This several thousand volts then goes to your spark plug to create the "spark".

The gunk is normal. The wires on the exciter coil are very small, so they break easily. The gunk is epoxy to help protect them.

The oil is also normal.

[wilkin250r]

So, now that you are asleep from the previous post, let's get down to business. How do we fix your problem?


Honestly, I'm stumped. It sounds like a CDI, but you said the new CDI is doing the same thing.

If it's not the CDI, the next likely component is your wiring. But you said you checked that, too.

You might have a bad connection in the kill switch and/or ignition switch. Try disconnecting the black/white wire and make sure it doesn't touch metal. If it runs perfect when this wire is disconnected, then go through your kill switch and look for a short to ground. Be aware, though, with this wire disconnected, you have no way to shut off your quad. If I do something like this, I usually remove the airfilter, and then put my hand over the intake to choke the air off when I want to kill it.

Beyond that, I'm not sure what it could be. You might end up replacing parts one at a time until the problem fixes itself. :ermm:

[ruffram]

I have been reading some old posts about people having ground problems. The only ground I can find goes to the bolt that holds the coil to the frame. Other people were running a wire from the ground to a motor mount bolt to ensure a ground. Would a bad ground cause the symptoms I am having? Also, i have used a multimeter to check resistance on the stator and it is within range, so i am pretty sure the stator is ok. Others have said something about the pickup coil and the clearance between it and the flywheel how can I check/adjust it? And, if the pickup coil or pulse generator is bad, would it be causing these symptoms? thanks for all the help I am very impressed with the level of technical advice on this board thanks

[ruffram]

Ok, double checked the ground wire today, filed it down to bare metal and still same problem. Now I am thnking pulse generator. Can the pulse generator create an intermitent spark?

[honda250xrider]

i've had the same problems and 1 do you have the grey wire and the grey and black wire coming from the right side of the motor going into your wiring harness plugged in, now second thing is it could be more than likely your stator, i've had the same problem before of them coming and going and ended up just needing a new stator and it sucks! i think i paid $228 new for one.

[ruffram]

I am thinking it is the pickup coil or pulse generator whatever they call it. Little black sensor just beisde teh stator in the side case. The stator looks ok really, and the headlight was working so i am going to get a new pulse generator like $40 from the dealer and see what happens.

[ruffram]

Ok this thing is driving me Crazy!!!! I have replaced the pulse generator or pickup coil on this thing and now it seems to make one bright blue spark when u kick it over but that is it. Doesn't seem to spark more than once. When bringing it to TDC and giving a good full strong kick it makes one bright blue spark every single time. I have changed coils with my CRF50 and does the same thing and my 50 runs perfect with either coil. I have replaced the CDI box with one from a running quad. I tried to pull start it for 1/4 mile and I got nothing.

While pull starting the headlight stays on which to me means the stator is good OR could it still be bad? ANy help here please. The stator OHM's out fine according the factory service manual. What should the spark look like when kicking it over? I am tempted to clamp the plug to the cylinder and pull start it in the dark to see what kind of spark it makes while the motor is cranking any ideas suggestions? Open to all thanks

[honda250xrider]

there is two seperate parts on the stator, one to run the headlights and one for the spark. Like i said i think it is your stator, i've had the same problems and it even sparked but it did not generate enough and would never start, i could be wrong it just seems you are having the same kind of troubles i was having.

[ruffram]

ok, i just hate to keep throwing parts at this thing with no results. My stator checks fine on the Ohm resistance which makes me think it is ok. Did yours check fine with the Ohm resistance test? Anyone seen one check fine with Ohm test on multimeter and still be faulty?

[honda250xrider]

yup mine checked out fine, but there is two seperate parts, you could be testing the lights instead of actually testing the faulty part if this is the case.

[dork]

sounds like a stator. put a new plug in it with a real small plug gap, like .010" or less and see if starts. that will make it easier to fire on less voltage. like 250xrider said there are 2 sets of coils on the stator, ones for ignition and ones for lights. also just because it ohms out ok, it still can be bad. best way is to swap out parts sometimes with electrical.

[ruffram]

I will try to narrow the gap and see what happens, i was afraid the stator was bad, but hoped that the ohm test meant it was ok. If the spark doesnt get better or worse does that mean anything? I dont' mind buying a stator if it will fix it but I hate to spend that much and not fix it.

[dork]

read this (http://www.exriders.com/vbb/showthread.php?s=&threadid=93608)

scroll down towards the bottom the post from Mickey Dunlap, he talks about a transistor is the harness that can short out. i'll look at my schematic, i think they show it. just one more thing to think about.

[ruffram]

I have thought about alot of things like that, but it seems that if I had a swithc or faulty wiring problem I would never get spark. IT makes spark every single time I bring it to TDC and give a good firm kick. HOwever it only seems to make one spark not a couple as the motor keeps rolling over. Especially with teh plug out, a good firm kick rolls the motor over well enough I should be getting a couple or three sparks not just one bright one

[wilkin250r]

I don't recall a transistor a few inches from the coil. I'll check on it in the next few days in the electrical schematic and on my own 87 250X.

Mickey Dunlap is a well-known engine builder, so he definitely knows a thing or two. Read what he says about the reverse wires and check to see if might be your problem.

As far as your headlight, that doesn't really tell you anything. Your stator has a section dedicated to lights, and a section dedicated to ignition, and they are completely independent. It's very possible to have one section be good, while one section goes bad. Think of it like your engine and transmission in your car. They work together, but one can be broken while the other works fine. Just because your headlight turns on doesn't necessarily mean your stator is good. (but since you said the resistance is within spec on the pulse and exciter coils, I'm inclined to believe your stator is good)

[ruffram]

I will double check the reverse wires but I don't think that it would spark at all if there was a reverse swithc problem and I am 100% sure they are connected, and I am showing a very good ground on that pin of the harness that connects to CDI box. at this point I will try narrowing the gap on the plug and seeing what it does. Anyone have a stator from a blown motor sitting around? I don't mind buying one to fix it, but hate to throw more money at it aimlessly