Hi everyone, I just picked up an 89 moto 4 yfm 250 the other day and can't get the thing to start... it is getting good spark and fuel. I've tried starting it with just gas and also starting fluid and can't get it to do much more than backfire and blow flames out of the air box. I took the carb off and took it apart and it is spotless (the guy I bought it from said he cleaned it). one thing I did notice that was that the cover over the timing gear was loose and I'm wondering if someone messed with the timing? I know how to set timing on a car, but how do I set and verify on an atv? Any help/pointers will be greatly appreciated. Thank you in advance.

 

Update.... I figured out how to check the timing and it appears that the timing is retarded by about two teeth on the cam gear when I line up the crank gear properly... which brings me to my next question, how do I get to the tensioner to adjust this? I was going to remove the left crank case cover to see but didn't wanna dump all my oil if I didn't have to... thanks again in advance for any help.