Grizzly 350 wont fire

Check oil level capacity, to ensure in specs. Check spark plugs, ensure its clean and correct plug for your quad.the only other could be is ign coil breaking down when warm. Check fire at plug when this happens. First ensure oil level is correct. Make sure your electric fan is on when bike is warmed up.

possible that the fuel tank is not venting properly

what year? pull cable under seat on some? (under plastic ) has looped cable , just pull it. along edge of seat on others small lever pull up towards seat.

see this link... should fix the problem
02 03 Reverse OR

for some reason you are not getting into reverse , there is no real reason it should stay in forward gears unless there is someting wrong with the shifter itself being in the wrong position this can happen take it off and reposition it and make sure your clutch is disengauging to shift gears , will it go into all gears or just 1 forward , ck into that and be a little more specific on the problem ,good luck

Best guess is the leads are off by one terminal. I have found that whatever was touched last is going to be where the problem is. Especially on a formerly running engine.

You said it ran, then you pulled the leads off. Well somewhere in the process something either didn't get put back together the same as it came apart OR another component got disconnected or possibly moved out of position to cause a 'no start' condition.

Look over the area, double, triple, or even quadruple check the firing order.

Hope this helps.

These quads have a thermostat-controlled radiator fan, which won't turn on until the engine is hot. Perfectly normal. Also, if the fan comes on, make sure you use the kill switch to turn the quad off, rather than just turning the key. This allows the engine to cool properly and will save your engine gaskets and other parts. It could take quite a while to cool down...my 2009 Grizzly sure does.

Hello if you ran out of gas i am not familiar with this motorcycle but honda and most street bikes the fuel petcock / fuel valve are vacuum actuated so when you run out of fuel you need to turn the fuel valve to primary to fill the carburetors once you get it started turn the valve back to the on position.
hope this helps.

check the main fuse

Check the carb boot were it attaches to the cylinder head and see if can notice any cracks or hole in it.