My brother in law picked up a slightly used Tao Tao 110 ATV last summer, only ran it a handful of times but it never ran exactly right until recently where it wouldn't start. So he asked me to check it out.


First thing I checked is for spark which it had. Determined it was a fuel delivery issue, pulled the carb and did a quick clean. Now the quad would start and run great but only with the choke on. While I had it running I gave it a quick blip of the throttle, it revved up nice and then came down and died. Would not start again. I lost spark. Swapped in a new NGK plug and still no spark, then replaced the coil with new unit and got spark back.


Pulled the carb again since there was still a fuel issue, thoroughly cleaned the jets along with the rest of the carb. Started it up and it idled great without the choke now, I adjusted the idle and it was running awesome. Pretty confident I solved the fuel issue. once again I gave it quick blip of the throttle, it revved up nice and then came down and died. Wouldn't start, I lost spark again. I can only assume its the coil again.


Any ideas what would cause this?

 

"I can only assume its the coil again."

Not necessarily, the number of times I have changed a component on a bike with an intermittent fault, thought I had cured it, only for the fault to recur. Intermittent electrical problems can be the devil to find.

 

Oh I believe that, theres obviously an electrical issues somewhere causing the coil to fail...

 

Have you tried putting the old coil back in? You may have a bad wire some ware and every time you swap out the coil its making connection again.

 

Ive actually wondered the same thing, going to have to try that out.