have problem with keeping this thing running.. will start eventually but wont idle and wont run longer than a minute or so. took the carburator in and had it rebuilt... new spark plug, changed fuel, new fuel filter and new battery.. please help

 

Have you checked the quality of the spark your getting? It could be the CDI box. Pull the plug and with it wired up ground it on the frame in a dark garage and turn it over watching spark. How did the old plug look?

Slydog

 

old plug is black, so is the new one. getting good spark checked that.

 

could be dirty aircleaner, or clean aircleaner thats been over oiled, try cleaning the airfilter and reoiling it very very litely, next would be a valve adjustment, probably never been done before.

 

ok. thanks for your input. have the air filter off at the moment i will try to find info on how to adjust the valves

 

If old plug is black then it is either running rich or not getting enough air, like the air filter cleaning "chineseatvmechanic" mentioned. I would be very cautious adjusting the valves if you have never done so before, as you can make it worse. It sounds like it is just running rich and fouling the plug out, so check air, fuel, and spark, along with the exhaust. I would also check the compression before touching the valves and see if you are getting enough compression. Best of luck..........

Slydog

 

unless a plug check was done when he first got the quad, we don't know if it's been running rich since he gotten the quad, most stock atv's have a tendency to run a little rich anyway since the manufacture jets the carbuators to run at sea level. black spark plug just means it eaither a fuel or a ignition problem, not just a carbuator problem only. poor ignition will also cause the spark plug to show a black reading. after a fuel system and ignition check and it still doesn't start i will do a valve adjustment next, it elimates the guess work and it only takes about 30 minutes to adjust the valves .

 

I agree stock they are a little rich, but he said the old and new plug are burning black. For a plug to be black your are not getting complete burn causing carbon deposits, which can be caused by not enough air (dirty air filter), a weak CDI module or bad plug, or too much fuel entering the combustion chamber for the amount of air incoming (jetting size or float stuck).

He has checked spark, fuel, and now the air filter but the engine dying after a minute has to be caused by losing spark (CDI or fouled plug) or not getting fuel or air. Since the air filter is not going to change just sitting there for a minute then it must be spark or fuel, or maybe the valves are so far out of adjustment causing the plug to foul and kill the motor.

chineseatvmechanic, are you saying the factory doesn't adjust the valves ?

Slydog

 

Not able to find spec on how to set the valve on the hi bird can anyone tell me the valve setting for it.

 

I think between .02 and .05 you should be fine