Polaris 400 Xplorer Won’t Run

[Kyle Meadows]

I am 17 and I don't have lots of money but I know my way around older 2 stroke dirtbikes but my grandpa gave me this four-wheeler and I have had nothing but issues with it. I went through gas tank/lines and the oil injection has been bypassed, I have mixed gas in the tank and it is for sure getting to the carb. I have cleaned the carb to the best of my ability. I can get it to try and start for a few seconds but won't run any longer than 5 seconds with or without ether. Please help

[Arizona]

You might want to check compression first and go from there

[Kyle Meadows]

8 minutes ago, Arizona said:

You might want to check compression first and go from there

It's electric start I just put compression test in and electric start?

[Frank Angerano]

Hey  @Kyle Meadows welcome to Quadcrazy. If compression was good and the engine/atv overall is in good shape the only common denominator here is the fuel pump.  I know fuel is getting into the carburetor bowl  and the engine will start up however the amount of fuel getting back into the carburetor is not sufficient.  So in essence the engine is running out of fuel before the bowl can fill back up. 
Thats why the atv has a pump!  
I would locate a new pump and install it as it should be and i have a feeling the engine will run fine.  
Thats my guess on what's happening anyway.     

[Kyle Meadows]

2 hours ago, Frank Angerano said:

Hey  @Kyle Meadows welcome to Quadcrazy. If compression was good and the engine/atv overall is in good shape the only common denominator here is the fuel pump.  I know fuel is getting into the carburetor bowl  and the engine will start up however the amount of fuel getting back into the carburetor is not sufficient.  So in essence the engine is running out of fuel before the bowl can fill back up. 
Thats why the atv has a pump!  
I would locate a new pump and install it as it should be and i have a feeling the engine will run fine.  
Thats my guess on what's happening anyway.     

I have not seen a pump and I have followed all gas lines. This is an older bike. It has spark and compression. Seems like something electrical is shutting it down

[Frank Angerano]

Im sorry i thought you wrote bypassed the fuel pump. Well it would not be electrical if it has spark. Is the float set properly? When you rebuild the carburetor was it all set right? Also was the oil bypass line capped off now that its bypassed ? It could be sucking in air. 
Double check that the throttle has no wires going into it. It would be a rev limiter but i don't think they had rev limiters that early.  
 

[06kfx440]

I had this problem on my Xplorer too. Check to see if the fuel lines are correct. If they are to big they will cause an air lock in the delivery. The way to fix it is take the line off the carb and remove it to the tank but don’t take it off the tank. Crack the valve so fuel fills the filter and beyond. Then put it back on the carb. Take the fuel tank cap off and crack the valve again. Your priming the fuel line. If that doesn’t work. Then the in tank screens are clogged or the valve is defective.


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[Jakelam]

It could be the air/idle screw is turned in too much-not getting enough air to the carb to allow fuel to flow efficiently, otherwise would look to clean the carb once again, make sure the fuel screw is set according to manual/specs...

[fireslayer]

Do these have drains in the crankcase below the crankshaft? If so, it could be loose or missing allowing air into the crankcase and causing lean condition and hard? no start issues.