intermitant spark

[regg187]

I am having intermitant spark. I am checking this with a spark tester also. fires up this morning, shut it off 20 min later no spark
exciter ohms are in range,pulser ohms are in range, light coil is 200 watt R.S rewind thats ohms are in range. ign coil & cap are new and ohms test out fine. I have been through the wiring harness and it is all solid with no breaks and 2 good grounds. Have the stop start switch disconnected. CDI has been switched out with another and when my original cdi sparks so will the other one. when 1 won't the other wont either. trigger coil is super close to tab on flywheel.What am I missing here, what happens when a rotor starts to loose its magnetism. could this be my problem

As soon as the spark checker shows spark, both cdis will fire it up and it fires in 1 or 2 kicks.

any one out there have problems like this?

[wilkin250r]

Hmm, very perplexing problem.

The lighting coil won't have any effect at all, so don't bother with that. The ignition and the lighting are two completely different and independent circuits. One can work while the other fails, so your lighting coils are obviously not your problem.

Don't rule out the CDI just yet. Did you pull the replacement CDI off another running quad? Did you try putting YOUR cdi on the other quad, just to verify it runs properly?


However, my first guess would still be in the wiring or the stator. I'm thinking you have a broken wire that sometimes makes contact, and sometimes doesn't. So try this. You have already measured the resistance on all components, right? Try taking some measurements when it DOES spark, and then again when it DOESN'T spark, and see if you can find a difference. When taking the measurements, try not to jiggle or disturb the wires, because if you have an intermittent contact somewhere, that movement can make or break it.

I'm an electrical engineer, I know a thing or two about electronics and magnetism. I can't see your stator losing magnetism, it just doesn't happen. You could possibly damage the magnets, and that can cause funny things, but they don't "loose" magnetism all by themselves.

[regg187]

I will try that this evening, When I went through the wiring harnes I removed it from the quad and check continuity through all wires. as far as the cdi I didn't check them in another quad, but it seems funny that when it will make spark, both cdi's make spark, when it won't make spark both cdi's won't make spark, like something before their place in the cycle is eitheir working or not, being the real cause of the spark.

[wilkin250r]

You are correct, with the troubleshooting you have done so far, it would be unlikely that the CDI is the problem. Like you said, when the spark is gone, it's also gone with the new CDI.

I'm just saying, don't rule it out yet, I've seen stranger things. Since it's a simple test to just throw it on the other quad, you may as well try it out.

[regg187]

Ok , I had spark last night exciter coil 140 ohm
had spark this morning same 140 ohm.
pulled stator to check coils, was rewound at ricky stators, no epoxcy on ign coils, strange my other stator has its coils covered in epoxy. ohms on exciter coil on other stator 210-220. big difference. epoxyd over the coils . noticed that the tops of the coils(closest to flywhell magnets) have a coating of something on them. my other stator has no coating on this area. scratche off this coating. same 140 ohm but also still has spark. pick up coils have same ohm for both stators 130
will have to go visit a friend today to plug in cdi's in a different quad to check them.
Is it possible that what ever the coating was on the stator ends was affecting the magnetic induction to the coils?
thanks Wilk for your input.

[400excaleb]

does your 4 wheeler run good for about 20 min of riding then just quits and wont start for about 3 min and then when starts it pops and sputters.

[regg187]

No, it will either have spark and run fine for as long as I run it. or have no spark and not fire for days, but then have spark and fire on 2nd kick, from not having ran for 3 weeks. it seems to be better after I scraped the 'epoxcy' off the ends of the coil winding posts. will know better on Mon if it has spark and fires still. I have had spark all day today!

[400excaleb]

Originally posted by regg187
No, it will either have spark and run fine for as long as I run it. or have no spark and not fire for days, but then have spark and fire on 2nd kick, from not having ran for 3 weeks. it seems to be better after I scraped the 'epoxcy' off the ends of the coil winding posts. will know better on Mon if it has spark and fires still. I have had spark all day today!
well mine when you ride it, it will run fine till you go to wide open throttle and then just die and will turn over but not fire or nothing, but if you wait for about 3 min then it will start but pops at high rpms. just the other day i was letting it warm up and it dies and will not start back up and has no spark. i changed the coil and rev box annd changed the plug and still no spark at all.

[wilkin250r]

The epoxy shouldn't have any effect. As a general rule, most adhesives are non-magnetic, and non-conducting.

Believe me when I tell you, I'm willing to try to help you out, but I don't know if I can. I'm stumped.

[regg187]

O.K. wilkin ,I have no spark and I hooked up my meter to the red/black off the stator , no spark plug in the cyl(for eazy kickin)range set for 50 ac. kick and trying to peg it self.. my guess exciter coil ok. sending voltage to cdi. next pulser coil what should happen when tab on the flywheel pass in front of pick up for pulser. should ohm raise or lower or stay the same. I'm thinking
cdi is getting its power from the ex coil, but doesn't know what to do with it , because of no signal to fire from pulse gen. sound plausible? tried cdi's in another quad and both worked fine.
one last thing. I noticed on the flywheel that the tab for the pulse gen had slight polished stripe on it. possible hitting of the tip on the pulse gen (slight) could this cause problem? thanks

[wilkin250r]

It might be a problem.

You are not going to get any real reading off your pulse generator. It only produces maybe a volt, and only for a very short duration. You would need an oscilliscope to read it. The signal from the pulse generator is used to calculate RPM (by measuring the time between pulses), and to tell your CDI the crankshaft position (which is why you have a flywheel key, it locks it to a specific position on the crankshaft). With this info, your CDI knows when to fire the plug.

The pulse generator needs two things to operate properly. First, it needs to be intact, no broken wires, and the pickup itself must not be broken. Second, it needs to be close enough to the flywheel to get a signal, but not so close that it hits it. If it's too far away, it won't function properly even if your ohms readings are within spec.

So, the pulse generator might be your problem, but it also might not be.

[regg187]

Well , I went ahead and ordered rs's new lightend flywheel, at least if that isn't the prob, then I still will have the benefit of the lightened flywheel. let you know in a few days, when it arrives.

[regg187]

Well, the new flywheel took care of the problem. I had spark all the time. I went ahead and got the dynatek cdi(non prog). I get a fat blue spark, on the iridium ngk's, even with the gap at 28-30. I am running the gap at 25 just for peace of mind. It takes no more than 3 kicks to fire it up, when it hasn't been started in a few days, and 1 or sometimes 2 when it is warmed up. My Orthoscoped knee is so much happier now!! Thanks for the help!