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hi guys, just a quick rundown. i started a thread because after searching i have not been able to find a thread with the same problems as what im seeing. i have a 2007 honda rancher 420 4x4 with the EFI. as of right now it will not start without spraying carb cleaner into the air intake. once it cranks it will not stay running unless you keep spraying it. when i disconnect the injector line i can see fuel coming out when i spin it over. the fuel pump relay clicks when i turn the key on. oh and i can here the IACV hum when the key is turned on. i have also pulled the injector and spun it over with it hooked up and it starts with a good spray and then it gets lighter and lighter till it has almost no spray. im at a loss guys! i think its a fuel issue but im not sure. i dont want to just start throwing parts at it. i really want to know what the problem is. also the previous owner did a top end job on it with a new piston, rings, and a new cylinder. i believe he told me he went with an oversized kit but im not sure.
 

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I fixed my neighbor's 420 Rancher by replacing the fuel pump. It was filthy varnished up with horrible ethanol fuel such that the pump would not spin. Worked great after the replacement. It was far too dirty to clean and the pump didn't even hum with power directly applied to its terminals.

Please don't overuse the starting fluid. It is fabulous as a diagnostic tool but the spray is tough on the cylinder wall oil film. This will eventually cause excessive wear in the piston rings and cylinder wall.

Rick
 

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I agree that the fuel pump seems suspect. After the initial burst, fuel pressure seems to be dropping over time. Do you have a way to measure fuel pressure?
 

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Fuel pump or clogged fuel filter.

Could also be partially clogged petcock, but first thing I'd do it put a new fuel filter on it and see if that fixes it.
 

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thanks guys. im going to try the fuel filter today and see if i can get it to crank. i understand about using to much fluid so far its just been one quick burst about 4 or 5 times to hear it run. i do not have a way of testing the fuel pressure but im thinking about ordering a fuel pressure tester and making an adapter to fit the injector line. ill update this evening after i play with it some more. i appreciate the feedback! i was already leaning towards fuel pump, glad to see my line of thinking is not crazy!
 

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alright guys i put a different pump motor on the bike and there is still no change. there is also a loud clanking when i spin it over while giving it throttle. could that have something to do with it? im stuck on this one. i have no idea where to check next. i pulled the injector with it hooked up and spun it over and it seems to be spraying better but it still will not crank. any ideas?
 
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