Need help bad

[300EXSibley]

Alright I put new timing chain on set timing at tdc both on flywheel and cam tried to start it back fired through carb. Went back and turned the timing 180 degrees. Tried to start it again nothing. Could a bent valve cause it to back fire through the carb. The only time I get anyt hing is when I was off 180 degrees or maybe I was timed just a valve might be bent. I don't know. This is my last question.

:(

[cals400ex]

this is what you need to do:

put the flywheel on the T mark. install cam sprocket on timing chain with two of the marks aligning up with the head. the other mark on the sprocket should face UP. now slide the cam in with the lobes facing down. torque the cam sprockets bolts down. do a dry run by turning the (i think 17mm) bolt on the flywheel with a rachet. make sure you turn it counterclockwise. turn it several times and then align the T mark up again. go to the other side and make sure those 2 lines are still even with the head. also make sure the 1 remaining line is facing up when the cam lobes are facing down. this line my be pointing down now if the lobes are up. however, if it is pointing down, go and turn the flywheel one more revolution and align the T up. now go back to the other side and make sure the 2 lines are flush with the head and the other one now should be up and at this point in time the cam lobes will be facing down again. if all the lines are where they need to be, your timing is good. however, it only takes one tooth off on the timing for the bike to not run or run like crap.