bike dies after 2-3 minutes of riding

when your riding my 93 cr 250 it will die after 2-3 minutes like it has fouled a plug, but you wait about 20 seconds and it will start again. i have cleaned my carb vents and made sure the gas tank vent is not clogged but it is still doing it. Also it will have a red spark if you check the plug after it has died but the plug looks tan still.

sounds like your coil is shot.

just switched the coil with the one in the 80 and same thing happened

could the gas cap itself be clogged?

could low compression cause this?

Could it be jetting related?

the bike dies exactly like it would if it fouled a plug, no surging its just like you hit the kill switch. You try to start it right away and it wont start, but if you wait about 20 seconds it will.

i just checked and it has good flow from the tank to the carb for sure.

he was talking about the vent on the cap, it will let fuel flow for alittle while and as the tank start to form a vacuum the flow gets low or stops. Try taking the cap off and blowing through the vent if you can blow through it, it should be good.

i just let the gas line run into a gas can for about a minute with good flow and then i put my finger over the cap vent and the flow stopped so im sure its getting good gas flow and thats not the problem

sounds like the vent is good.

Sounds electrical, maybe a grounded out wire somewhere perhaps. What has a red spark?

the plug has a red spark, i know its electrical and ive tried switching coils with the 80 and unplugging the kill switch. The stator checked out good, i changed the plug, and checked every electrical connection. So ive narrowed it down to the cdi, does this sound right? It just weird because if this cdi is bad this bike will be on its 3rd cdi, the last one made it extremely hard and almost impossible to start when warm. This cdi makes it die when warm. I have had it idling for 10 minutes and it didnt die because it never warmed up. So what im thinking is the cdi is sensitive to failures when the motor warms up. Sorry if im just kinda babbling on here but im really trying to get this problem fixed so i can ride this weekend or next weekend at the latest.

A red/orange spark means that you have reduced voltage. So yes, the CDI is culprit.

Now as to why they keep going out I don't know. Are you using some cheap generic ones? Is your CDI installed in the correct location? Are all the wires good and clean and tight?

yes they are oem denso cdi's, and they are hooked up correctly just as they would be from the factory, this cdi on it now came off a bike that has sat outside for 5 years, so that may be why

so...the stator tested good, the coil tested good (i swapped them anyway with the same results), so the only thing left is the cdi which has to be bad. Since cdi's are known to have failures when the get warmed up and the failure sometimes leads to low spark voltage, im 95% the cdi is bad. Now, i could get a used one for about $80, or i can get a complete msd programmable ignition with cdi, coil, plug wire and spark enhancer with battery and charger for $135, it is practially brand new. Has never been used but has been mounted. What do you think? i think a brand new complete ignition system will last longer than an already 18 year old cdi.

I'm surprised nobody has mentioned a warped head. Sometimes if the head is warped, it will stay sealed until the aluminum expands with the heat optimal operating temps. When it expands, it allows coolant from the cooling jacket around the cylinder to enter the combustion chamber and foul the plug. It could also be a leaky head gasket that only leaks when the aluminum expands.

Not saying that's the problem, Although, it definitely a possibility if everything else checks out ok.

im not loosing any coolant so i would assume that the head is fine

im not loosing any coolant so i would assume that the head is fine

Well, depending on how much is being lost over what period of time, you may not notice it going away for a long time. It doesn't take very much to foul a plug. How long has it been acting this way?

but the plug is dry right when it dies, and if the plug fouled it wouldnt start 20 seconds later like it does

True. I agree with the CDI posts. sounds like it's on it's way out.

well got my new cdi......same f'n thing, i am at a complete loss, the only thing i can thing of now it maybe the stator

but the plug is dry right when it dies, and if the plug fouled it wouldnt start 20 seconds later like it does

see if it dies while manipulating the choke lever on and off. If it stays running then the bike is starving out of fuel. And carb needs to be thoroughly rebuilt and ultrasonically cleaned.

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