when i bought this atv it ran good then one day it started to back fire and died pulled plug intermitten spark after a lengthy process of eleimatation replaced CDI box and it ran great rode it about a 30 hours it started to back fire and know no spark again unplugged everything but what it needs to run and still no luck. cant afford to keep buying CDI's for this can any one help.

 

Welcome to the forum! Should be a 95 Explorer (first year they came out) Did you remove the black wire from the reverse limiter module and see if it runs? Also disconnect the black kill circuit wire from the cdi and see if you have spark. Could have a short in the wiring or left control switch that could be shorting out. If you already have done both of these and no change,then you need to ohm out the stator pulse coil and source coil wires that plug into the cdi to see if this is the the main problem. Don't know if this is correct for your model(can't remember all specs),but the pulse coil white to white/red should be 90-115 ohms resistance,stator source coil red to red/black 244 ohms? Seems like most of the older 400s I had electrical problems with were from stators. OPT

 

Thanks for the response I tried some of that dident know the specs on the pulse coil the book dosent help much there. ill give those things a try and let you know. thanks.

 

Ok finally got the chance to work on it again. pulse coil is 104 ohms. and source coil is 227 ohms. also unplugged black wire to rev limiter and it started but is back fireing i have a spare rev limiter going to change that and see if it helps. any other thoughts cant get to it tonight. and thanks for your help so far.

 

I wouldn't replace the limiter! Just something to go out again. Sounds like you're getting close since it starts.Make sure you don't have too much slack on the thumb throttle,could be the etc switch contacts in the throttle housing could be touching causing the back firing. Plus not a bad idea just to pull the recoil and clean around the pulse coil and flywheel. OPT

 

can i bypass that etc switch? im not using the thumb throttle put a twist throttle on insted.

 

Did it start to backfire as soon as you put the twist throttle on?
i'm betting it did
I have never taken an etc off. I imagine there are two wires connected to it that need to be tied together.
lets see who chimes in, someone may have done this before

 

White wire from the etc switch goes into the limiter module which you basically eliminated when you pulled the black wire. You can start first by disconnecting the white wire,if no change then disconnect the red/white wire from the etc switch harness to see if the back firing stops. I wasn't in the habit of trying to defeat this switch. Have had several guys install a dirt bike twist throttle housing on the grip area and added a nylon string drilled through the thumb throttle to operate,keeping the original housing.Not too bright of an idea and dangerous. Just my OPT

 

First this is my brother in laws 4 wheeler and hes the type that likes to patch things so you can see its a fight to get him to buy new parts. and he has trouble with the thumb throttle he has a bad hand. I think it did start back fireing when we did that. can you tell me what that switch does if its important ill try to get him to hook it back up.

 

the switch will sense a stuck throttle. ignition only works right if the switch is making contact. which happens when you depress the throttle, if you were to back off the throttle from WFO the spring in the carb should pull the throttle back to an idle. If that doesn't happen, throttle thumb lever goes slack, which will loose contact with the switch activating the rev limiter.