Backfiringggg!!!

put the new kickstart spring in and everyhting seemed to be working good.. let the bike idol for like 2 min then shut off..... when i tried to restart wouldn't start...checked the plug looked fouled so i changed it... kicked it over 100 times in 2 days then finnallly BANG like a gunshot.... after the bang i kicked it a couple more times and it started ruff but it started, took it for a ride around the block and brought it back when i got back neighbors were waiting to biotch at me for the noise so i couldn't see if it would start again... why would it back fire like that, once it was running no backfiring just when i was kicking it....
 
check ur reeds, one time i was going 6th gear pinned and i heard a loud ass pop come from the motor, and i checked the reeds and one of the petals flew out and into the engine and flew out the pipe i got lucky.
 
The key way that holds the flywheel in place on the crank for correct timing?
You just have to remove the flywheel cover to check.
 
thanks cuz i am gonna trouble shoot this weekend if i start it up and it starts fine then i guess it was just from sitting or the gas or a fluke something if not then im gonna check the keyway thanks for the info would there be any other symptoms if the keyway was messed up
 
Definitely check your timing first. If your key is in and in good condition your timing should be fine. The other thing that might have happened is with the seal around the kick. If your motor has been together for a while and has any age on it, the crank seals may be worn. When you put the kick spring in, you may have rolled the lip on the seal around the kick causing an air leak. The air then may have the ability to be pulled through the seal, through the transmission case and then through the crank seal causing a condition where it tries to run like it's lean. Try taking 2-3lbs of air pressure and send it back through the vent tube and see if you here it coming out of the air box or pull the carb and listen for it out of the reed cage. You may have to rotate the kick to move your piston down to the ports.
I did the same thing and I just about killed myself to figure it out.
Word of caution, air pressure is a very powerful thing so be careful with it you could blow crank seals out or ruin the seal between your case halves. When you replaced your transmission case, did your electrical tape and grease your kick shaft or use an Oring in the groove?
Just some stuff to look for. Hope it helps.