no start , backfire 400ex

[mcgrath]

heh guys, fresh rebuild. new crank ,cyl,piston. turn engine over and sounds like it wants to start once in a while but won't .back fires occasionly. Im 99percent sure timming is on but one thing Im not positive is when the rod broke if a valve got bent? also when I choke it and press the throttle I feel a "tapping" in the throttle. Any info would help, Im not much of a 4 stroke guy, I usually just deal with 2 strokes. thanks

[storms400ex]

look at the carb make sure everything is clean

[JHracing4]

it sounds like valves to me, check to make sure the rod didnt bend or break a valve and make sure they are all in spec.

[ae13291]

im pretty sure the exhaust valve is bent, on my buddies crf250r the valve adjustment got so bad that it dident start and there was a big flame out the exhaust, the exhaust valves were staying open

[mcgrath]

yeah right on checked timing, carb and of course bent intake valves, not too bad but any is too much. Too bad I missed it when assembling engine. oh well just more parts right?! thanks for the input guys.