I have looked at a lot of different possabilities but I have no answers yet. What I do know is when I pull the plug and look for spark I get spark. I also know if I put my thumb on the plug hole well craning I can feel some compression. I have replaced the plug and tried stating fluid but it still will not start. Any ideas why I would have spark and when I add starting fluid it still does not start. Could the spark be week? Any other suggestions? This is a 2002 Raptor 80.

 

You need three things for it to run: fuel, compression and spark. You confrimed you have spark and compression so that leaves fuel. Sometimes it is hard to get things to lite off with starting fluid. Make sure the new plug is gapped correctly and that the cap is tight on both the plug and plug wire. Spray a little bit of starting fluid in the plug hole and screw the plug in quickly. This should get it to pop over a couple times.

 

It's the valves. My kids had a badger and the valves (intake) would always get tight fast. Adjust them, it'll fire right up.

 

I'm having the same exact issues with mine right now....I took it into the dealership and one of the service techs tell me the chokeplate screw fell out and into the intake and damaged the piston. WHAT! He added that he has seen this in 2 other raptor 80's before in the last few months. He said it's fairly common, but I cannot believe that if Yamaha knows of this issue they haven't done something to correct it.
To add fuel to the inferno, my warranty expired 3 months ago! This thing is practically brand new! Only ridden by my little girl. I need to call Yamaha and see if they can help me on this???

 

well i have a raptor 80 and it allways wont start in the cold cause of the battery