As far as I know (i'm learning to) you can't "set" the timing on a quad. The timing is fixed and runs off the crank position sensor. The computer will advance the spark when needed but I dont think this is user selectable. vacuum leaks will mess with timing and idle.
If you read through some of these threads you will get answers to changing and checking the timing chain
You can't set the timing, it's controlled by the computer. If you think the engine is missing or not timed properly, it is probably 1/2 of your Ignition Control Module. Replacement is VERY easy and cost me $75 CDN about 5 years ago. Good luck.