Listen to this, I came home today and saw my 16 year old son with his motto 4 hooked up to his car with jumper cable's. The ATV ran fine except for a weak battery. He had been using a battery charger to start it but my neighbor had borrowed it a few days ago. so I guess he thought it was OK to use his car. Well now it will not start Ii checked the fuse and its OK, its getting fire to the plug. My question is what did he fry could be the coil or is there a voltage regulator on the ATV. Maybe someone here can give me some ideas before i take it to the shop.
Thanks
PS please don't say take the jumper cables away, WE HAD A LONG TALK ABOUT THAT ALREADY[img]i/expressions/face-icon-small-mad.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img]

 

Well it really shouldn't be a problem with using the jumper cables. You're still talking about 12 volts in both of the systems, but the car has way more amperage or "cranking amps" than the quad battery does.

I don't really have any suggestions for you right now... make sure all of the connections are tight first. All you said was that it wouldn't start. You didn't say if it cranks or not. Give us a little more info and hopefully we can get this sorted out for ya. I don't think there's any need to take the quad to the shop yet.

 

Black widow
Thanks for your reply, No the engine will not start. All the engine will do is turn over and over as long as you engage the starter. I removed the plug and rotate the engine it has compression, I also replaced the spark plug with a new one. Also replaced the battery with a new fully charged one. If you remove the plug and ground it to the cylinder head and turn the engine over there is spark to the plug. If you crank the engine with the plug in the engine it seems to sound as it may be turning slower, and there is some low backfire. I have not tried pushing it off I will try this tomorrow by towing it with my ATV.
As I said Thanks for your reply maybe you can give me some ideas.
dirtroadrider

 

Well let's see... when the plug sparks is it a good snap or a light orange colored spark? Even though you're getting spark it may not be very strong. Could be something like a bad ignition pickup, bad coil, or just simply a bad ground on one of these components.

I would also do a few preliminary checks to make sure that the bike is getting fuel. I guess first and easiest way to do this would be to pay attention to what the exhaust smells like after turning it over for a little bit. If it smells like gas then at least fuel is getting into the engine. It could also be getting too much fuel... evidence of this will be present in the form of a wet spark plug.

I don't know about these engines in particular but I know that on my friend's Moto 80, they had an issue with the exhast valves sticking in the valve guides. You might do some asking around at local shops and see if this is a potential issue for your engine.

I hope I'm pointing you in the right direction... It's so hard to guess at what might be wrong when it's not sitting in front of me!!

Good luck and write back with more info if you have it.

 

When I checked the spark again it has very little spark (IMHO- it is weak compared to my other ATVs spark). So I tested the coil and and its OK,(checked at my local shop)yes its getting fuel. I also removed the plastic covers to inspect the complete wiring harness for loose connections, and found nothing loose or wiring chafing. so could it be the ignition pick up? Does the amplifier have anything to do with the spark or is more or less to maintain the battery charge?
thanks everyone for their input concerning my sons ATV trouble.
thanks
dirtroadrider[img]i/expressions/face-icon-small-smile.gif[/img]

 

i am a service manager at a automotive shop (toyota), and we occasionaly see a plug look good but when you put them under compression, they act funny. i know you said it was new. what i would be wondering is, (1) it takes more energy to fire the plug under compression. weak spark may turn into no spark. (2) a friend had one, and it had a bad connection at a connector under the handlebars. by the time we found it, it was flooded so bad we drug it behind a old indian he had (now thats worth something!)
hope that helps, and i agree with i think it was the first guy. so hard to help if it's not sitting in front of you[img]i/expressions/face-icon-small-smile.gif[/img]
good luck
aaron

 

Ok... we're narrowing it down. I'm assuming that the plug wire is attached directly to the coil and that nothing on the plug wire itself looks bad, such as scuffing/burned spots etc.

Oh.. just remembered something.... what cc is the bike??

See.. I'm thinking that this has to be an easy and cheap problem to fix. You just don't see that many electrical components on quads and motorcycles going bad.

If you haven't already... make sure that all of the ground connections are tight... battery cable and where it attaches to the engine, and the coil ground in particular. And when I say tight.. make sure they're clean and tight. Corrosion has a tendancy to work into things.

I hope I'm helping you! Good luck!