back fireing trouble

[drilldaddy]

I have a 2003 660 it will turn over but it back fires while you are cranking on it and it wont start can any one tell me what i need to do.

[warj1990]

Most likely
Start with checking the timing on the motor, that is most likely the cause, sorry I sold my 660 and the repair manual with it so I am no help on the timing.

Less likely
Next up is a compression check, you may also want to pull the head off the motor and reseat the valves (reguardless of compression check).

[Grizzly4fun]

x2 on checking the timing. Check marks on the flywheel and cam gear at same time. If these aren't set correctly, set them. Then hand turn, not with starter, the crank a few complete turns to ensure no interference with piston and valves. If ok then give it a whirl. May need new tensioner, etc
If interference, then maybe broken woodruff key and rotor/flywheel has rotated.
Good luck!

[Transam355]

i would adjust the valves

[Jobbe700]

Same thing on my 700...it was a burnt sparkplug i just gave it a new plug and now its working fine